UL Approval Canadian Standards Association Atmosphères ExplosiblesEuropean ConformityIECEx Approval

Features

  • Fully-Approved Explosion-Proof Pulse Input Flow Rate/Totalizers
  • NPN Open Collector, PNP, TTL, Switch Contact, Sine Wave (Magnetic Pickup Coil), or Active Square Wave Inputs
  • Top Display: Five 12-Segment Alphanumeric Characters, 0.7" (17.8 mm)
  • Bottom Display: Eight 14-Segment Alphanumeric Characters, 0.4" (10.2 mm)
  • Display Mountable at 0°, 90°, 180°, & 270° (No Tools Required)
  • CapTouch Through-Glass Button Programming with Normal and Delayed Modes
  • Red Backlight for Alarm Conditions, Enable and Disable Backlight from Menu
  • 8-Digit Total & Grand Total Display, Up to 13 Digits Using Both Lines
  • Display Rate & Total Simultaneously
  • Bi-Directional Flow Detection Via Digital Input
  • Non-Resettable Grand Total
  • Display Previous Total and Previous Grand Total with Time-of-Day Reset Feature
  • Reset Total / Grand Total with CapTouch Button, Digital Input, or Time-of-Day Feature
  • Automatic or Manual Batch Control
  • K-Factor Calibration or Scaling with Up to 32-Point Linearization
  • Gate Function for Rate Display of Slow Pulse Rates
  • (2) Open Collector Outputs Standard; Assignable to Pulse, Alarm, Timer, or Stopwatch
  • (2) Optional Solid-State Relays; Assignable to Alarm, Sample, Timer, Batch Control, or Stopwatch
  • Optional Isolated 4-20 mA Analog Output
  • Free PC-Based MeterView XL USB Programming Software
  • 9-30 VDC, Battery, or 4-20 mA Output Power Options
  • Battery-Powered Momentary Backlight & Display Sleep and Off Modes to Extend Battery Life
  • Modbus RTU RS-485 Communications Standard on DC & Battery Powered Models
  • On-Board Data Logging of up to 2,032 Records and Modbus Accessible Data
  • Password Protection for Settings, Total & Grand Total
  • UL Listed as Explosion-Proof / Dust Ignition-Proof / Flame-Proof
  • CSA Certified as Explosion-Proof / Dust Ignition-Proof / Flame-Proof
  • ATEX and IECEx Certified as Explosion-Proof
  • Operating Temp Range: -40 to 75°C (-40 to 167°F)
  • Installation Temp Range: -55 to 75°C (-67 to 167°F)
  • Conformal Coated PCBs for Dust & Humidity Protection
  • Flange for Wall or Pipe Mounting; Loop for Stainless Steel Tag; Holes for Tamper-Proof Seal
  • Explosion-Proof Aluminum & Stainless Steel Enclosures with 1", 3/4", or M20 Connections
  • 3-Year Warranty

Overview

Explosion-Proof Loop-Powered Flow Rate/Totalizers with Advanced Display and Control Features

The PD6938 ProtEX+ pulse input flow rate/totalizers can be installed in a variety of areas (hazardous, dirty, wet, corrosive, hot, or cold) to provide convenient and informative display of flow rate and total from any pulse output flowmeter. These instruments will accept a variety of pulse inputs, including slow pulse rates. They can be powered from a battery, 9-30 VDC, or the 4-20 mA output loop, have on-board datalogging capabilities, come with explosion-proof approvals, and can be ordered with optional 4-20 mA output and two relays.

The PD6938 can operate down to -40°C and is certified by the agencies to be installed in areas that get as cold as -55°C. The display will cease functioning below -40°C but no damage will be done to the instrument.

One of the most convenient features of these instruments is their dual-line display, which is typically used to display the flow rate on the top display and flow total, flow grand total, or a tag on the bottom display. The top display has five characters and the bottom display has eight characters for clear indication of tags, units, or alarm messages. Further enhancing the display on these instruments is a 20-segment bargraph and backlighting that can turn red during an alarm condition.

The PD6938 ProtEX+ is available in aluminum and stainless steel enclosures that are designed for easy use and installation. The process connection is available in M20, 3/4" NPT and 1" NPT and there are two other conduit holes for field wiring. Field wiring is made to removable screw terminals and the display module can be oriented in 4 different positions to accommodate different mounting configurations and requires no tools to install. The display has been designed to optimize viewing angle.

Free, PC-based, MeterView XL software that connects to the meter via a micro-USB cable is available for programming and setup of the instruments. Four CapTouch through-glass buttons are available to operate the instrument without removing the cover.

All models come equipped with two open collector outputs and a digital input. There are also models available with Modbus RTU RS-485 communications, two solid-state relays, and isolated 4-20 mA analog output options. The open collector outputs are useful for alarm indication or pulse output. The digital input can be used to reset the total, to start/stop a timer/stopwatch, to start/stop a batch, and more. The relays can be programmed for alarm indication, on/off control, or simple batch control.

Other PD6938 Models Available

PD6938-HA Explosion-Proof and Intrinsically Safe Flow Rate/Totalizers
PD6938-HA

Exp-Proof and I.S. models

PD6938-IS Intrinsically Safe Flow Rate/Totalizers
PD6938-IS

Intrinsically safe only models

PD6938-GP General Purpose Flow Rate/Totalizers
PD6938-GP

General purpose models

Front

PD6938-EX in Aluminum
PD6938-EX-AL
  • Flow Rate/Totalizer
  • Aluminum
PD6938-EX in Stainless Steel
PD6938-EX-SS
  • Flow Rate/Totalizer
  • Stainless Steel

Connections

Connections for DC Powered -D5M Option
Standard
  • (2) Open Collector Outputs Standard (150 mA max); Assignable to Pulse, Alarm, Timer, or Stopwatch
  • Digital Input for Remote Operation of a Single Task (Reset Total, etc.)
Options
  • (2) Loop-Powered Solid-State Relays; Assignable to Alarm, Batch Control, Timer, or Stopwatch
  • Isolated 4-20 mA Analog Output
  • Modbus RTU RS-485 Communications

Power Options

The PD6938-EX explosion-proof models offer power options including battery, DC with battery backup, DC only, output loop, or output loop with battery backups.

Battery Backup

Select models are available with a battery backup power option. For these models, the primary power source is supplied by either DC power or the output loop, depending on the model. The battery is used during battery backup operation. If there is a power failure of the primary power source, the battery will instantly take over powering the meter. There will be no display interruption nor any information loss.

Battery Status Indication

Battery indicators on the display alert users of the power status of the PD6938.

IndicatorStateDescription
FlashingMeter checking battery status
SteadyMeter using battery power
FlashingLow battery (replace battery)

Designed for Long Battery Life

LCD Sleep Mode
LCD sleep mode turns the LCD off after a user programmable amount of time, while all inputs and outputs continue working. Press any button for 2 seconds to wake up the display.
CapTouch Delayed Mode
In Delayed mode, the buttons enter into a low sensitivity state (sleep) after 20 seconds of inactivity. Press any button for 2 seconds to wake up the buttons.
Momentary Backlight
The backlight is enabled by default. If the meter is battery powered, then the backlight is automatically set up to momentarily turn on for 10 seconds when any button is pressed.
Turn Meter Off
To extend battery life even more, the meter can be turned off completely when it is not in use. Press and hold the Menu button for 5 seconds to turn the meter on or off and follow the on-screen instructions.

Display Features

PD6938 Pulse Input Flow Rate/Totalizer with Bargraph

Wide Variety of Display Capabilities

In addition to the most common setup of flow rate on the top display and flow total on the bottom display, these meters can be set up for a variety of display configurations as shown in the following examples.

See the instruction manual for additional display possibilities for both top and bottom display.

Flow Rate and Toggle Between Units and Tag Flow Rate and Toggle Between Units & Tag

Display flow rate on top, toggle between rate units and tag on bottom

Flow Total and Toggle Between Units and Tag Flow Total and Toggle Between Units & Tag

Display flow total on top, toggle between total units and tag on bottom

Flow Total and Flow Grand Total and Toggle Between Units Flow Total & Flow Grand Total and Toggle Between Units

Display total flow on top and Grand Total flow on bottom, and display toggles between values and units. Notice Grand Total can use different units than Total.

Commas on bottom display

Commas Make it Easy to Read Big Numbers

The bottom display is set to show a comma separating the thousands and millions place by default if a numeric value is being displayed. This feature can be disabled or enabled using the Comma menu.

13-Digit Total Enabled

Using 13 Digits to Display Total

The top and bottom displays can be setup to display a 13-digit total (9,999,999,999,999). The total will roll over to zero when it exceeds the limit.

Meter with Red Backlight

Backlight Turns Red on Alarm

The backlight is standard on all ProtEX+ meters. It provides optimum visibility in any lighting condition and it can be programmed to turn red for alarm conditions. The backlight may be enabled or disabled using the Backlight menu. The backlight is enabled by default. If the meter is DC powered, then the backlight is constantly on. If the meter is battery powered, then the backlight is on according to the setting selected under the System – Battery - Display menu.

Meter with Bargraph

Bargraph Provides Quick Understanding

The 20-segment bargraph helps users get a quick understanding of where their process is at. The bargraph can be programmed to represent either rate, a percentage of the rate, total, or it can be disabled.

Dual Scale Feature

Dual-Scale Display Feature

Users can use the dual-scale feature when they want to show the same input in two different scales. For instance, the example above shows an application where the meter displays the input in gallons per minute and cubic feet per minute.

14-segment Characters Comparison

14-Segment Characters

Notice how much better letters like “T”, “N” and “K” appear as 14-segment characters on the bottom display vs. 7-segment characters found on other meters.

Predefined and Custom Units

The meter has the most common predefined rate and volume units. If the desired unit is not available, the user can program a custom unit.

Total & Rate in Different Units

The user can select to display total in different units than the rate. For instance, a customer could measure flow rate in gallons per minute and total in acre-feet by simply selecting AF (acre-feet) units for the total. Additionally the user can enter a custom unit and conversion factor to display the total in any unit of measure.

CapTouch Through-Window Buttons

All PD6938 meters are equipped with four capacitive sensors that operate as through-window buttons so that they can be operated without removing the cover (and exposing the electronics) in a hazardous area or harsh environment.

CapTouch buttons are designed to work under any lighting condition and to protect against false triggering. They can be turned off for security via a switch on the display module

To actuate a button, press one finger to the window directly over the marked button area. When the cover is removed, the CapTouch buttons can be used after the meter completes a self-calibrating routine ( flashes). The sensors are disabled when more than one button is pressed, and they will automatically re-enable after a few seconds ( off).

CapTouch Buttons Operation Modes

The CapTouch buttons have two modes of operation: Normal and Delayed.

Normal

Normal is the factory default setting. This mode is recommended for programming the meter or when immediate operation of the buttons is needed.

Delayed

Use the Delayed mode to prevent accidental trigger of the buttons. In the Delayed mode, the buttons enter into a low sensitivity state (sleep) and they ignore quick button presses after 20 seconds of inactivity. To wake up the buttons, press and hold any button for more than 2 seconds, the buttons respond normally.

Turning Off CapTouch Buttons

The CapTouch buttons can be turned off for security by moving the slide switch located on the display module to the Off position.

Switch to Disable CapTouch Buttons

Outputs

PD6938 meters come with two open collector outputs as standard and two solid-state relays and 4-20 mA output as options. The open collector outputs and relays generally operate in the same manner, with the major exception being the open collectors are not available for batch control and the relays are not available with pulse output features. The open collectors and relays can be controlled either automatically or manually. The alarm status (with a unique flashing red message for each of the two relays and open collectors) will show on the display even with no output wired.

Two Open Collector Outputs

The meter is equipped with two NPN open collector outputs that may be set up for pulse outputs, alarms, timed pulses, stopwatch on/off, or disabled. Pulse outputs can be set to transmit the rate, total or grand total. Output 2 may be used to generate a quadrature output based on the other open collector output. An output test mode is also selectable to generate pulses at a constant programmable frequency. The open collectors are commonly used to generate a pulse for every user-defined amount of flow that has been generated. For instance, the meter can be programmed to generate a pulse for every 100 gallons of flow.

Two Optional Solid-State Relays

The meter is optionally equipped with two solid-state relays that may be set up for alarms, sample, timer, batch control, or stopwatch. The relays are rated at 250 VAC/DC @ 0.5 A for resistive loads and 38 VA @ 0.3 A, 250 VAC/DC max (Safe Area only) for inductive loads. Alarms are available based on the PV value or the digital input.

Optional Isolated 4-20 mA Output

The isolated analog output signal can be configured to represent the process variable (flow rate, total, or retransmit). While the output is nominally 4-20 mA, the signal will accurately accommodate under- and over-ranges from 1 to 23 mA. The output can be reverse scaled such that the meter’s high calibration value outputs 4 mA and the meter’s low calibration outputs 20 mA.

Sampling Relay

A relay set to sample will trigger when the total or grand total value has incremented by a programmed amount. The relay can be programmed to stay on for a specified amount of time. For example: if a relay is set to sample the total with a COUNT of 1,000 and a TIME of 10 seconds, the relay will energize for 10 seconds each time the total increments by 1,000 (e.g. 1000, 2000, 3000).

Resetting the Open Collectors and Relays

The open collectors and relays (alarms) may be programmed to reset in the following ways:

  • Automatic (AUTO): Alarm will reset automatically once the alarm condition has cleared.
  • Automatic/Manual (AUTO.MAN): Alarm will reset automatically once the alarm condition has cleared but can also be reset using the Enter button (or whichever function key is set to acknowledge) at any time.
  • Latching (LATCH): Alarm must be reset manually and can be done so at any time. Press the Enter (ACK) button at any time to clear the alarm.
  • Latching with Reset after Cleared (L-CLEAR): Alarm must be reset manually and can only be done so after the alarm condition has cleared. Press the Enter (ACK) button after the alarm condition has cleared to reset the alarm.

Batch Control

The PD6938, when ordered with the two solid-state relays, can be used as a simple, one or two-stage batch controller. The user enters a preset and preclose value and sets the meter to either count up or count down. The top display will show the total and the bottom display will show the preset batch amount. The function keys are automatically changed so that F1 starts a batch, F2 opens the preset menu to allow the preset value to be changed, and F3 pauses/stops the currently running batch. Batching can be either automatic or manual.

Batch Control Operation Example

The following example shows how two-stage manual batch control functions with a PD6938. This setup will establish a 55-gallon preset for the batch, with a main valve (high flow) that will close at 50 gallons, and a trickle valve (low or restricted flow) that will close at 55 gallons. Because the first batch overruns by 0.10, the batch preset will be changed to 54.90 for the next batch to compensate for overrun.

If only one-stage batch control is desired, do not assign relay 2 to batch. The following pages show illustrations of how the above settings control the batch operation. The display assignment shown is the default.

ParameterSettingFunction
RELAY
OUTPUT 1
RLY 1
BATCH
Press Enter to assign relay 1 batch parameters.
BATCH
COUNT
UP or DOWNSetup batch to count up or down.
BATCH
MAXIMUM
100.00 GALThis setting prevents the operator from entering a preset value that exceeds a safety limit for the batch process.
BATCH
MODE
MANUAL or AUTOPress Enter to select manual or automatic batch control.
BATCH
PRESET
55.00 GALEnter the batch size.
BATCH
DELAY
ON & OFFEnter the On & Off time delays for relay 1, if desired.
ParameterSettingFunction
RELAY
OUTPUT 2
RLY 2
BATCH
Press Enter to assign relay 2 batch parameters.
BATCH
PRECLOSE
YES
PRECLOSE
5.00
Set the pre-close value to 5 to close the valve being controlled by relay 2 so it closes five gallons before reaching the preset.
BATCH
DELAY
ON & OFFEnter the On & Off time delays for relay 2, if desired.
RELAY
MESSAGE
MSG
RELAY 1
Enter a message to be displayed while relay 1 is on, if desired.
MSG
RELAY 2
Enter a message to be displayed while relay 2 is on, if desired.
Manual Batch Control

The manual batch control feature is used for batch processes that the operator wants to start manually. It can also be used where the batch size needs to be manually adjusted for each batch. The batch can be controlled by the button on the meter or the digital input.

Batch System Setup

System Setup

Both valves are closed with an empty barrel in place. The batched total is displayed in the upper display, the preset is selected for the lower display.

Batch Start

Batch Start

The START button or (F1) is pressed. Both valves open. The barrel begins to fill.

Preclose Valve

Preclose Valve

When the batch total reaches a value of 50.00 (Preset [55.00] – Pre-close [5.00]) the full-flow valve closes. The fill rate of the tank slows as a result.

Completed Batch

Completed Batch

When the batch is complete, the restricted flow valve closes. If overrun occurs, then the preset must be adjusted to compensate for the overrun amount. The next batch will only start after the START button or (F1) is pressed.

Overrun Correction

Overrun Correction

To compensate for overrun in the previous batch, adjust the preset to 54.90, so that the next batch is accurate (55.00).

Manual Start of Next Batch

Manual Start of Next Batch

A new, empty, barrel is put in place and the START button or (F1) is pushed to manually start the next batch.

Change Batch Size

Change Batch Size

While the process is stopped, a new preset fill amount may be selected with the Batch key (F2) for a different size barrel.

Pause/Stop

Pause/Stop

At any time, press the STOP button or Stop key (F3) once to pause the process, or twice to cancel the batch, which stops the process.

Resume Batch

Resume Batch

If the batch has been paused, then press START button or (F1) to resume the batch process.

Automatic Batch Control

The automatic batch control feature is used for batches that start automatically once the previous batch is completed. There is no opportunity for the operator to change the batch size between batches. The batch can be controlled by the button on the meter or the digital input.

Batch System Setup

System Setup

Both valves are closed with an empty barrel in place. The batched total is displayed in the upper display, the preset is selected for the lower display.

Batch Start

Batch Start

The START button or (F1) is pressed. Both valves open. The barrel begins to fill.

Preclose Valve

Preclose Valve

When the batch total reaches a value of 50.00 (Preset [55.00] – Pre-close [5.00]) the full-flow valve closes. The fill rate of the tank slows as a result.

Completed Batch

Completed Batch

When the batch is complete, the restricted flow valve closes. If overrun occurs, then the preset must be adjusted to compensate for the overrun amount.

Start Delay

Start Delay

After the batch is completed, the operator removes the full barrel and places an empty barrel; the new batch starts automatically after 60 seconds (Time Delay).

Automatic Start of Next Batch

Automatic Start of Next Batch

The next batch begins automatically after 60 seconds, both relays activate and both valves open.

Pause

Pause

At any time, press the STOP button or Stop key (F3) once to pause the process.

Resume Batch

Resume Batch

If the batch has been paused, then press START button or (F1) to resume the batch process.

Stop Process

Stop Process

At the end of the shift, press STOP button or Stop key (F3) twice to stop the batch process.

Totalizer Capabilities

PD6938 flow rate/totalizers can be programmed for a wide variety of totalizer applications. They can display total, grand total, or non-resettable grand total; the rate can be displayed with a time base of seconds, minutes, hours or days. The user can program a totalizer conversion factor, a non-resettable grand total, password protection, and several total reset methods.

Totalizer Conversion Factor & Multiplier

The user can enter a totalizer conversion factor that allows the meter to display total in different units than the rate. For instance, a customer could measure flow rate in gallons per minute and total in millions of gallons. A multiplier may be selected to automatically display the value in kGAL, MGAL, etc. Use the custom units to display the total in any unit of measure including units in languages other than English.

Total Alarms

The two open collectors and the two relays can be set up to alarm when the total reaches a user-defined set point. A variety of reset modes are available and the user can also program time delays and fail-safe operation.

Totalizer Password Protection

The total and grand total can be password protected so they can be reset only by authorized personnel.

Total Stored in Non-Volatile Memory

Total and grand total values, and all programmed settings are stored in non-volatile memory for a minimum of ten years if power is lost.

Non-Resettable Grand Total

The user can set up the grand total to be non-resettable by selecting YES for PERMLOCK in the Advanced - Grand Total - Reset menu. Once this is done, the grand total can never be reset.

Low-Flow Cutoff

The user may program the meter for a low-flow cutoff such that the meter displays zero below this point, regardless of the input value.



Remote Total Reset

The total can be reset via an external contact closure on the digital input.

Advanced Features

Automatic K-Factor Unit Calibration

The meter may be scaled using the K-Factor, or conversion factor, function. Most flowmeter manufacturers provide this information with the device. Enter the K-Factor menu and select the units defined with the K-Factor (example: pulses/gal), the decimal point with highest resolution possible, and program the K-Factor value. The meter automatically calculates the flow rate using the K-Factor value and the units selected. The rate can be displayed in any time-base and decimal point resolution selected in the Display menu.

Custom Scaling and Live Input Calibration

Instead of K-Factor setup, the meter can be scaled to any span relative to the input pulse rate span (i.e. if you knew the pulse input span for gallons but wanted to display the rate and total in liters). No external signal is required.

Live input calibration can also be performed. This is done at any two points along the scale. Using this method, an operator can set a “best fit straight line” for nonlinear input spans.

Gate Function for Slow or Unsteady Pulses

The gate function allows for a rate display of slow or unsteady pulse rates. Using the programmable gate, the meter is able to display pulse rates as slow as 1 pulse every 9,999 seconds (0.0001 Hz). The gate function can also be used to obtain a steady display reading with a fluctuating input signal. There are two settings for the Gate, low gate and high gate.

Modbus® RTU Serial Communications

Select PD6938 models are available with Modbus RTU RS-485 communications and can communicate with any Modbus master device. Below are just some of the actions you can perform using Modbus.

  • Read rate, total, grand total, max, and min display values
  • Read the on-board 2,032 record data log
  • Access all parameters remotely for programming or verification

Multi-Point Linearization

Meters are set up at the factory for linear function with 2-point linearization. Up to 32 linearization points can be selected for rate under the linear function. Multi-point linearization can be used to linearize the input for non-linear signals to convert level to flow using weirs and flumes with complex equations.

MeterView XL software makes it easy to program up to 32 points.

Multi-Point Linearization Using MeterView XL Software

Bi-Directional Flow

The PD6938 can be set up to process bi-directional flow by connecting the bi-directional switch from the flowmeter to the meter's digital input (DI) terminals, setting up the digital input to activate the flow function (Reversed or Forward), disabling the low-flow cutoff feature, and enabling negative count (if the total is expected to go negative).

Data Logging

The PD6938 is capable of data logging up to 2,032 records, each containing date, time, rate, total, grand total, relay & open collector states. The user can choose what information to log, when, and how to log it. The log file can be downloaded using the MeterView XL software and it can be saved in .csv file format.

Real Time Logging

A real time clock records the date and time for each data log entry. The data may be recorded using the Log Time feature up to 4 times per day at specific times entered by the user. When the log is full, it will roll over and continue to log, deleting the oldest data. The data may also be recorded using the Log Interval feature, recording the data every programmed time interval, from 1 minute to 24 hours.

When the Interval log is full, recording will stop, keeping all data until logging is started again.

On-Screen Access to Data Log Entries

Easy On-Screen Access

The data log entries are easily viewable on the meter LCD. Data points may be navigated by viewing the date and time, rate, total, or grand total amounts. A known log may be jumped to immediately, avoiding a lengthy search for data. With through-window buttons and a customizable menu, the data log can be accessed quickly and without the need for external control stations or serial communications, for easy viewing in the field.

Physical Features

ProtEX+ Aluminum & Stainless Steel Enclosures

ProtEX+ Physical Features Overview
NEMA 4X / IP68 Rated Enclosure

NEMA 4X Enclosure

The ProtEX+ enclosure provides serious protection from the elements, high impact, corrosion, and dust. It is NEMA 4X/IP68 rated. In addition, the ProtEX+ enclosure provides protection against electrical interference and its extensive worldwide agency approvals allow it to be installed virtually anywhere.

PD6938 Mounted to a Pipe

Easy Pipe Mounting

The ProtEX+ comes with a built-in flange. This allows easy mounting to walls or pipes using either a PDA6846 Zinc Plated Steel or a PDA6846-SS Stainless Steel 2" U-Bolt Kit. A slot on the back of the enclosure makes it easy to center the unit on a pipe.

PD6938 Wide Angle Viewing

Wide Viewing Angle

The window and display module have been optimized to provide a wide viewing angle of approximately ±40°; nearly twice that of the competition.

PD6938 with Tamper Seal

Tamper-Proof Capability

The instrument can be made tamper-proof by inserting a wire through the built-in loop on the base of the enclosure and a hole in the lid of the enclosure and securing this wire with a lead seal.

PD6938 Rotatable Display Module

Rotatable Display Module

The display module can be rotated in 90° increments providing added mounting flexibility. Plus the various conduit connections allow a variety of installation options.

PD6938 with Stainless Steel Tag Attached

Stainless Steel Tag Attaching Loop

The enclosure is equipped with a loop at the top to easily attach a PDA-SSTAG stainless steel tag.

USB Port on Display Module

USB Port for Easy Connection to Free MeterView XL Software

A USB port located on the display module allows it to be connected to a PC for use with free MeterView XL software. The meter is powered by the USB connection during programming, if a 4-20 mA loop is not connected.

Conduit Opening

Three Threaded Conduit Openings

The PD6938 ProtEX+ comes with three 3/4" NPT threaded conduit openings as standard. It's also available with M20 conduit openings, or with two 3/4" NPT and one 1" NPT bottom conduit openings.

Conduit plugs available that are sold separately include the PDAPLUG75 3/4" NPT 316 stainless steel conduit plug with approvals and the PDAPLUGM20 M20 316 stainless steel conduit plug with approvals for models with M20 conduit openings.

Operational Features

There are two ways the user can interact with the ProtEX+ to perform a variety of useful functions: programmable function keys and the digital input.

Programmable Function Keys

The three CapTouch buttons labeled F1, F2, and F3 can be programmed as function keys to perform a variety of meter functions simply by pressing on the window over the button. These include resetting the total, operating the batch control functions, resetting the meter’s relays or open collectors, starting and stopping timers, and displaying max/min values. The default settings for the function keys are:

ButtonDescription (Default Settings)
Press to display grand total. Continue pressing to cycle through max, min, rate, and total displays.
Press to access the Reset menu. Press F1 to scroll through the options. Press F3 to reset the currently displayed parameter.
Press to acknowledge all manually resettable relays or open collectors.
Press to lock/unlock the display value after pressing the F1 key.

On-Board Digital Input

A digital input is standard on ProtEX+ meters. This digital input is programmed identically to the function keys. The input is triggered with a contact closure between DI+ and DI-, or with an active low signal. For a complete list of Digital Input settings available, see Function Keys & Digital Input Available Settings in the instruction manual.


Except where noted all specifications apply to operation at +25°C.

Display

DisplayDual-line LCD with backlight.
Both lines alphanumeric.
Top: 0.7" (17.8 mm) 5 digits, 12-segment
Bottom: 0.4" (10.2 mm) 8 characters, 14-segment
Display may be programmed to turn red and flash a user-defined message on alarm condition.
LCD SleepNever, 1, 2, 5, 10, 20, 60 min
Default: 10 min when battery powered; press any key for 2 sec to wake up the display.
All inputs and outputs continue working.
Turn Meter Off/OnPress & hold the Menu key for 5 sec and follow the on-screen instructions. This feature helps extend battery life.
Top Display5 digits (-9999 to 99999) or 5 characters
(all capital & most lower-case letters)
Bottom Display8 digits (-9,999,999 to 99,999,999; separated by commas) or 8 characters
(all capital & most lower-case letters)
BacklightNormal: white LED (enabled by default)
Alarm: red LED (default)
DC powered: steady on
Battery powered: momentary (default: 10 sec)
Output loop powered: varying intensity based on 4-20 mA output current
Bargraph20 segments (100% label at top fixed)
Assignable to rate, total, or off
Scale: 0 to 100%
Display AssignmentTop & bottom displays can be assigned to rate, total, grand total, etc. See instruction manual for a complete list of assignable parameters.
Decimal PointUp to four decimal places on top display and up to seven decimal places on bottom display
CommasCommas to indicate 1000s
(e.g. 88,987,628) on bottom display only
Alarm IndicationProgrammable: red backlight, flashing display, alarm symbol ⚠, bargraph segment flashes on alarm.
Custom Alarm MessagesProgrammable for each relay/open collector: 8 characters maximum; displayed every 10 sec for 1 sec on bottom display. May be turned off.
Display Update RateAmbient > -10°C: 1 Update/Second
Ambient = -20°C: 1 Update/2 Seconds
From -20°C to -40°C the update rate slows down
1 second for every -2°C (e.g. at -24°C, 1 update/4 seconds).
Below -40°C the display is not readable, but all the inputs and outputs work correctly.
OverrangeTop: 99999
Bottom: 99,999,999 (flashing)
UnderrangeTop: -9999
Bottom: -9,999,999 (flashing)

General

Programming MethodFour CapTouch through-window buttons when cover is installed. The CapTouch buttons can be used with the cover removed. Free PC-based USB MeterView XL programming software.
EnvironmentalOperating temperature range: -40 to 75°C (-40 to 167°F)
Storage temperature range: -55 to 85°C (-67 to 185°F)
Installation temperature range: -55 to 75°C (-67 to 167°F)
(The display ceases to function, however inputs and outputs continue to operate)
Relative humidity: 0 to 90% non-condensing
Printed circuit boards are conformally coated
RecalibrationRecommended at least every 12 months.
Max/Min DisplayMax/min readings reached by the process are stored until reset by the user or until power to the meter is turned off.
PasswordThere are three separate passwords available that can be set independently of each other: Main, Total, and Grand Total. The Main password prevents access to the meter Programming Mode. Total and Grand Total passwords prevent resetting the total and grand total, respectively.
Non-Volatile MemoryTotal and Grand Total values, and all programmed settings are stored in non-volatile memory for a minimum of ten years if power is lost.
Power Options9-30 VDC Powered, 2 W max
Battery Powered or 9-30 VDC Powered with Battery Backup
Loop Output Powered (30 VDC max)
Loop Output Powered with Battery Backup
Data LoggingUp to 2,032 records, recorded 4/day at specific times or at defined time intervals. Record contains date, time, rate, total, grand total, and open collectors & relays states.
Data Logging ModesContinuous: The log data will wrap around, erasing the oldest records to save the new records. Banks of 16 records will be erased at a time.
Stop when full: The log will stop recording when full and “LOG FULL” is displayed every 10 sec.
ConnectionsRemovable screw terminal blocks
Display terminals: accept 16 to 30 AWG wire
Relay terminals: accept 12 to 26 AWG wire
4-20 mA output: accept 16 to 30 AWG wire
Tightening TorqueDisplay terminals: 2.5 lb-in (0.28 Nm)
Relay terminals: 4.5 lb-in (0.5 Nm)
4-20 mA output terminals: 2.5 lb-in (0.28 Nm)
Overall Dimensions5.25" x 5.65" x 4.80" (133 x 144 x 122 mm) (W x H x D)
WeightAluminum: 5.1 lbs (2.3 kg)
Stainless Steel: 9.4 lbs (4.3 kg)
Warranty3 years parts and labor. See Warranty Information and Terms & Conditions for complete details.

Enclosure

Material-AL Models:
ASTM A413 LM6 die-cast aluminum, copper-free, enamel coated
-SS Models:
ASTM A743 CF8M investment-cast 316 stainless steel
GasketFluoroelastomer
Rating-AL/-SS: NEMA 4X, IP68 Explosion-proof
Color-AL: Blue
-SS: Silver
WindowBorosilicate glass
ConduitsTwo 3/4" NPT threaded conduit openings. M20 conduits are available.
See Ordering Information for details.
Conduit Stopping PlugSold separately
FlangeBuilt-in flange for wall and pipe mounting.
Tamper-Proof SealCover may be secured with tamper-proof seal.
Instrument Tag LoopBuilt-in loop for securing stainless steel tag
Overall Dimensions5.25" x 5.65" x 4.80"
(133 x 144 x 122 mm)
(W x H x D)
WeightAluminum: 4.8 lbs (2.18 kg)
Stainless Steel: 9.0 lbs (4.08 kg)

Input

InputPulse or square wave:
0-5 V, 0-12 V, or 0-24 V; TTL; NPN or PNP
Open collector: 100 kΩ pull-up to 2.8 V
Switch contact: 100 kΩ pull-up to 2.8 V
PNP transistor: 100 kΩ pull-down to ground
Active input: 100 kΩ pull-up to 2.8 V
NPN strong: 10 kΩ pull-up to 2.8 V (Do not use with battery power)
Maximum Frequency: 100 kHz
Minimum Pulse Width: 5 µs
Threshold SettingLow (V)High (V)
Active/NPN0.51.8
Active/NPN High2.84.8
Magnetic Pickup CoilSensitivity: 10 mVp-p to 24 Vp-p
Maximum Frequency: 40 kHz
Note: 10 mVp-p @ 300 Hz max
Sensor Power5 VDC @ 5 mA
Enabled in the Advanced – System menu
Minimum Input Frequency0.0001 Hz
Minimum frequency is dependent on high gate setting (rate display)
Input ImpedancePulse input: Greater than 75 kΩ @ 1 kHz.
Open collector/switch: 100 kΩ pull-up to 2.8 V
Contact Debounce Filter Programmable contact debounce filter.
Input signal frequency speed selections:
Disable: Greater than 100 kHz (no filter)
Fast: 1,000 Hz
Medium: 240 Hz
Slow: 100 Hz
AccuracyRate: ±0.02% of calibrated span ±1 count
Total: Every input pulse is counted
Temperature Drift2 PPM/°C from -40 to 75°C ambient
FunctionK-Factor: 0.000001 to 9,999,999
Rate: Linear (2-32 points)
Low-Flow Cutoff0.1 to 999,999 or disable. Point below at which the display always shows zero.
HART TransparencyThe 4-20 mA output does not interfere with existing HART communications.

Rate/Totalizer

Rate DisplayTop display: -9999 to 99999;
Bottom display: -9,999,999 to 99,999,999 (with commas)
Total & Grand Total DisplayTop display: 0 to 99999;
Bottom display: 0 to 99,999,999 (with commas)
13-Digit Total & Grand TotalUp to 9,999,999,999,999 using both lines with 13-digit total feature enabled.
Total Decimal PointUp to four decimal places on top, up to seven decimal places on bottom.
Total decimal point is independent of rate decimal point.
TotalizerCalculates total based on input pulses and rate units to display total in engineering units. A custom factor must be programmed if using custom defined units.
Time BaseSeconds, Minutes, Hours, Days
Totalizer RolloverTotalizer rolls over when display exceeds 99,999,999 (9,999,999,999,999
if 13-digit limit enabled). Relay status reflects display.
Total & Grand Total ResetVia CapTouch button, external contact closure on digital input, automatic based on time of day, or MeterView XL.
Time of Day Total & Grand Total ResetFour programmable reset times. The total and grand total can be set up to reset at a time of day every day or any day.
Previous Total & Grand TotalTotal & grand total are saved prior to applying the reset command.
The previous totals can be read via the F1 function key and the Modbus registers.
Total & Grand Total Reset PasswordsTotal and grand total passwords may be entered to prevent resetting the total or grand total unless a password is entered.
Non-Resettable Grand TotalGrand total reset may be disabled through the meter interface. Grand total reset may be permanently disabled by selecting YES at the PERMLOCK menu.
CAUTION
• Once the Grand Total has been programmed as “non-resettable” the feature CANNOT be disabled.
Non-Volatile MemoryTotal and Grand Total values are stored in non-volatile memory for a minimum of ten years if power is lost.

Batch Control

MethodsAutomatic or Manual, count up or count down
Manual Batch StartPressing F1 function key starts the batch
Manual Batch Pause/StopPressing F3 once pauses the batch, pressing it twice cancels the batch
Automatic BatchingThe PD6938 can be used as an automatic batch controller where batches run continuously without operator input
Batching Relay OperationSingle or dual-relay batching with optional preclose for two-stage operation
Batch PresetSet via F2 function key anywhere between 0.0001 to 99,999 based on batch total decimal point. If batch total is assigned to bottom, the preset can be up to 8 digits.
Batch PrecloseFor two-stage batch application, a preclose value can be set to close the main flow line.
Automatic Batch Restart Delay1 to 9,999 seconds. The batch will automatically restart after completion of the last batch.

Common Open Collector & Relay Specifications

NumberTwo open collectors & two relays
High or Low AlarmUser programmable for high or low alarm
Alarm Deadband0-100% FS, user programmable
Output AssignmentAlarm, Timer, Stopwatch, or Disable
Alarm Output SourceAssign to rate, total, grand total, or digital input
On & Off Time Delay0 to 9,999 seconds
Fail-Safe OperationIndependent for each open collector and relay.
Fail-safe on, the output is on under normal conditions.
Fail-safe off, the output is on under alarm conditions.
Alarm OperationAutomatic, automatic with manual override, latching (manual reset anytime), latching with reset after cleared (manual reset only after alarm has cleared)
Alarm IndicationProgrammable: loop-powered red backlight, flashing display, alarm symbol ⚠, bargraph segment flashes on alarm.
Custom Alarm MessagesProgrammable for each relay/open collector: 8 characters maximum; displayed every 10 sec for 1 sec on bottom display. May be turned off.
Alarm AcknowledgeCapTouch ACK button or external digital input resets output and screen indication.
Auto InitializationWhen power is applied to the meter, open collectors and relays will reflect the state of the input to the meter.
Timer OutputOne-shot or Continuous
Off Time Delay: 1 sec to 99:59:59 (hrs:min:sec)
On Time: 1 sec to 99:59:59 (hrs:min:sec)
StopwatchOutput turns on when started and off when stopped.

Open Collector Outputs

RatingIsolated open collector, sinking NPN
5-30 VDC @ 150 mA maximum
Output AssignmentPulse, Alarm, Timer, Stopwatch on/off, or Disable
Pulse Output SourcePulse output based on Rate, Total, Grand Total, or Test Frequency, Alarm, Timer, Total Reset, Stopwatch on/off, or Disable
Pulse Output Factor0.000001 to 999,999.9
Pulse Width0.25 ms @ 2 kHz; 500 ms @ 1 Hz; 50% duty cycle
Pulse Output Frequency2,000 Hz maximum
Quadrature Pulse OutputAvailable for Output 2
(90° behind Output 1) 500 Hz max
Alarm Output SourceAssign to Rate, Total, Grand Total or Digital Input

Solid-State Relays

Rating250 VAC/VDC @ 0.5 A resistive
38 VA; 250 VAC; 0.3 A pilot duty (inductive)
13 VA; 250 VDC; 0.3 A pilot duty (inductive)
Noise SuppressionMetal oxide varistors across outputs
Relay AssignmentAlarm, Sample, Timer, Batch, Stopwatch on/off, or Disable
Alarm Output SourceAssign to Rate, Total, Grand Total, or Digital Input
Relay RuntimeMeter will keep track of how long each relay has operated and display this information.
Relay CyclesMeter will keep track of how many times the relays have cycled and display this information.

4-20 mA Transmitter Output

Accuracy±0.05% FS ±0.001mA
Output SourceRate, total; reverse scaling allowed
Scaling Range1.00 to 23.0 mA
DisableHigh impedance state, less than 1 mA
CalibrationFactory calibrated:
0 to 100 GAL/Sec = 4.00 to 20.00 mA
Underrange1.0 mA, 3.5 mA, or 3.8 mA, or Off; user selectable
Overrange20.5 mA, 20.8 mA, 23.0 mA, or Off; user selectable
Isolation500 V input-to-output
Temperature Drift0.003 mA max from -40 to 75°C ambient
External Loop Power Supply7.0 VDC to 30.0 VDC maximum
Output Loop Resistance10-750 Ω @ 24 VDC; 10-1100 Ω @ 30 VDC
(External resistance to maintain accuracy)

On-Board Digital Input

FunctionRemote operation of front-panel buttons, acknowledge/reset relays, reset total, reset max/min values, start/stop batch, etc.
Contacts2.1 VDC on contact. Connect normally open contacts across G and +
Logic LevelsLogic High: 2.4 to 30 VDC (max)
Logic Low: 0 to 0.9 VDC

Serial Communications

ConnectionRS-485, 3-wire; Isolation: 500 V.
Non-isolated micro-USB.
ProtocolModbus® RTU
Meter Address / Slave ID1 - 247
Baud Rate1,200; 2,400; 4,800; 9,600; 19,200; 38,400; or 57,600 bps.
Transmit Time DelayProgrammable between 0 and 199 ms
Parity/Stop BitEven, odd, or none with 1 or 2 stop bits
Byte-to-Byte TimeoutMax of 1.5 character times or 2.25 ms
Note: Refer to the ProtEX+ and VantageView+ PD6938 Modbus® Register Tables located at www.predig.com for details.

MeterView XL Programming Software

AvailabilityFree download from www.predig.com/meterviewxl
System RequirementsMicrosoft® Windows® 10 & 11
CommunicationsUSB 2.0 (Standard USB A to USB B) Cable provided
ConfigurationConfigure all parameters on the meter. Configure meters one at a time.
Configuration FilesGenerate with or without meter connected; Save to file for later use.
USB Power ConnectionThe meter is powered by the USB connection during programming. There is no need to apply external power.
Note: The meter will not be damaged if external power is applied to it during programming.
WARNING
• The meter should only be connected to a computer while it is located in a safe area.
Data Logging ReportThe on-board data log can be downloaded via the USB or the RS-485 connection.
Saved as “.csv” file format.
PC Data LoggingMeterView XL can be used to data log directly to a computer connected to the meter via the USB or the RS-485 connection. The user can select what to log and at what interval.
  • Rate
  • Total
  • Grand Total
  • Open collector triggers
  • Relay triggers
  • Hold/unhold outputs
CompatibilityPrograms created for VantageView+ and ProtEX+ can be run on either meter. No other program sharing is permissible.

Battery

Battery life is dependent on how the meter is used. Backlight should only be used momentarily (10 sec on). Modbus should rarely be used on battery-power, it requires approximately 26 mA. See battery life tables below for details.


-EX Models (Options: A & M) A-Cell

Battery Type3.6 V Lithium (Li-SOCl2), non-rechargeable
P/N: PDABAT36A1-PACK
Battery Life
Operating Condition @ 2,000 HzEstimated Service LifeSuggested Replacement Interval
Monitoring only, backlight off17 months15 months
LCD sleep*, minimal CapTouch use, backlight off28 months25 months
100 Hz open collector 1&2 outputs, minimal backlight use12 months10 months
Battery ReplacementReplace only with a Precision Digital original Model PDABAT36A1-PACK

-EX Models (Options: B & N) C-Cell

Battery Type3.6 V Lithium (Li-SOCl2), non-rechargeable
P/N: PDABAT36C1-PACK
Battery Life
Operating Condition @ 2,000 HzEstimated Service LifeSuggested Replacement Interval
Monitoring only, backlight off37 months32 months
LCD sleep*, minimal CapTouch use, backlight off61 months53 months
100 Hz open collector 1&2 outputs, minimal backlight use26 months21 months
Battery ReplacementReplace only with a Precision Digital original Model PDABAT36C1-PACK

Battery Life with Modbus Continuously On

A-Cell138 hours
C-Cell296 hours

*LCD sleep: Press any key to wake up the display. All input & outputs continue working in LCD Sleep mode.


General Compliance Information

Electromagnetic Compatibility

EMC Emissions• CFR 47 FCC Part 15 Subpart B Class A emissions requirements (USA)
• ICES-003 Information Technology emissions requirements (Canada)
• AS/NZS CISPR 11 Group 1 Class A ISM emissions requirements (Australia/New Zealand)
• EN 55011 Group 1 Class A ISM emissions requirements (EU)
• EN 61000-6-4 Emissions requirements for Heavy Industrial Environments - Generic
EMC Emissions and ImmunityEN 61326-1
EMC requirements for Electrical equipment for measurement, control, and laboratory use – industrial use

Hazardous Area Approvals

ULExplosion-Proof for use in:
      For Class I, Division 1, Groups B, C, D
      Class II, Division 1, Groups E, F, G
      Class III, Division 1; T6
      Class I, Zone 1, AEx db IIC T6 Gb
      Zone 21, AEx tb IIIC T85°C Db
      Tamb = -55°C to 75°C
      UL Type 4X, IP66 / IP68
      UL File Number: E494837
CSAExplosion-Proof for use in:
      Class I, Division 1, Groups B, C and D
Dust Ignition-Proof for use in:
      Class II/III, Division 1, Groups E, F and G; T6
Flame-Proof for use in:
      Zone 1, Ex d IIC T6
      Ta = -55 to 75°C.
      Enclosure: Type 4X & IP66/IP68.
      Certificate Number: CSA 11 2325749
ATEX Explosion-Proof for use in:
      ATEXII 2 G D
      Ex db IIC T6 Gb
      Ex tb IIIC T85°C Db IP68
      Ta = -55 to 75°C
      Enclosure: Type 4X & IP66/IP68
      Certificate Number: Sira 10ATEX1116X
IECEx Explosion-Proof for use in:
      Ex db IIC T6 Gb
      Ex tb IIIC T85°C Db IP68
      Ta = -55 to 75°C
      Enclosure: Type 4X & IP66/IP68
      Certificate Number: IECEx SIR 10.0056X

MeterView XL Programming Software

Free, PC-based, MeterView XL software that connects to the meter via a micro USB cable is available for programming and setup of the meters. This software greatly simplifies the programming process and also allows the user to save configuration files for later use. The meter will also be powered by the USB connection so no additional power is needed during programming.

MeterView XL Software
For more information visit www.predig.com/meterviewxl

Dimensions

Front View
Side View
Bottom View

Connections

DC Powered Models (-D Option)

Open Collectors, Digital Input, RS-485, DC Power
ConnectorDescription
OC1Open Collector 1
OC2Open Collector 2
RS-485RS-485 Modbus RTU
Digital InputG, +
PowerV+, V- (9-30 VDC)
Pulse Input
ConnectorDescription
C+Magnetic Pickup Coil
S-Signal -
S+Signal +
SPSensor Power (5 V @ 5 mA)

-DNM Base Meter (2 Open Collectors and RS-485 Modbus RTU Standard)
-D2M Option (2 Solid-State Relays)
-D3M Option (4-20 mA Output)
-D5M Option (2 Solid-State Relays and 4-20 mA Output)

DC Powered with Battery Backup Models (-A and -B Options)

Open Collectors, Digital Input, RS-485, DC Power
ConnectorDescription
OC1Open Collector 1
OC2Open Collector 2
RS-485RS-485 Modbus RTU
Digital InputG, +
PowerV+, V- (9-30 VDC)
Pulse Input
ConnectorDescription
C+Magnetic Pickup Coil
S-Signal -
S+Signal +
SPSensor Power (5 V @ 5 mA)
-ANM and -BNM Base Meter (2 Open Collectors and RS-485 Modbus RTU Standard)
-A2M and -B2M Options (2 Solid-State Relays)
-A3M and -B3M Options (4-20 mA Output)
-A5M and -B5M Options (2 Solid-State Relays and 4-20 mA Output)

Loop Output Powered Models (-C Option)

Open Collectors and Digital Input
ConnectorDescription
OC1Open Collector 1
OC2Open Collector 2
Digital InputG, +
Pulse Input
ConnectorDescription
C+Magnetic Pickup Coil
S-Signal -
S+Signal +
SPSensor Power (5 V @ 5 mA)
-C3N Base Meter (2 Open Collectors Standard + 4-20 mA Output)
-C5N Option (2 Solid-State Relays and 4-20 mA Output)

Loop Output Powered with Battery Backup Models (-M and -N Options)

Open Collectors and Digital Input
ConnectorDescription
OC1Open Collector 1
OC2Open Collector 2
Digital InputG, +
Pulse Input
ConnectorDescription
C+Magnetic Pickup Coil
S-Signal -
S+Signal +
SPSensor Power (5 V @ 5 mA)
-M3N and -N3N Base Meter (2 Open Collectors Standard + 4-20 mA Output)
-M5N and -N5N Options (2 Solid-State Relays and 4-20 mA Output)

Wiring Diagrams

Explosion-Proof Wiring

Pulse Input Connections

Signal connections are made to a four-terminal connector. The following figures show connections to various flowmeter types. There are no switches or jumpers to set up for the input. Setup and programming are performed through the CapTouch buttons or PC-based software.

Flowmeter Powered by External Supply (Active)
Bi-Directional Flowmeter Connections
Flowmeter Powered by Internal Sensor Power (5 V @ 5 mA)
Self-Powered Magnetic Pickup Flowmeter (Coil)
NPN Open Collector Input
Switch Contact Input (Reed)
PNP Sensor with External Power
DC Power Connections

Models with battery power may optionally be connected to DC power and the battery will function as backup power when DC is lost. The same power supply may be used to power other circuits including a PNP-type sensor, however, to maintain input isolation, a separate power supply must be used to power the isolated 4-20 mA transmitter output.

Digital Input Connections

A digital input is standard on the meter. This digital input is connected with a normally open contact across DI+ and DI-, or with an active low signal applied to DI+ and DI-.

RS-485 Serial Connections

The RS-485 three-wire serial connection is standard. The cabling used for an RS-485 serial communications network should always be a high-quality cable such as Belden 8162 or Alpha 6203C. Signal ground is always recommended.

IMPORTANT
  • To connect the meter to the MeterView XL software using the RS-485 Modbus connection use a PDA8485 USB to RS-485 converter.


RS-485 2-Wire & Ground Serial Connections


RS-485 4-Wire & Ground Serial Connections
4-20 mA Output Connections

Connections for the 4-20 mA transmitter output are made to the connector terminals labeled mA OUT. The 4-20 mA output must be powered from an external power supply.

Solid-State Relay Connections

Relay connections are made to two-terminal connectors. Each relay’s C terminal is common only to the normally open (NO) contact of the corresponding relay.

Open Collector Outputs Connections

Open collector output 1 and 2 connections are made to terminals labeled O1+ and O1-, and O2+ and O2-. Connect the alarm or pulse input device as shown below.

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