PD6602/03/04 Loop Leader Process Meters

These loop-powered 1/8 DIN digital panel meters can be installed virtually anywhere to provide convenient and informative displays of any 4-20 mA signal. One of the most convenient features of these instruments is their dual line display which is typically used to display the process variable on the 5-digit alphanumeric top line and the units or a tag on the 8-digit alphanumeric bottom line. Another common setup is to display the input in one scale on the top line (such as feet) and another scale on the bottom line (such as gallons). Both of these lines use 14-segment, alphanumeric characters for clear indication of tags, units or alarm messages.

Further enhancing the display on these instruments is a 20-segment bargraph available on the PD6604/8 that also includes a numeric value of the percentage the bargraph represents.

There is even a model that displays level in feet and inches for customers who prefer to see their levels represented that way rather than in decimal format.

These loop-powered meters can be installed virtually anywhere because they get their power from the 4-20 mA loop and therefore require no separate power source. And they only drop 1.5 V (4.7 V with backlight), so they add very little burden to the loop. Additional features that allow these instruments to be installed virtually anywhere include a NEMA 4X, IP65 front panel, an operating temperature range of -40 to 167°F (-40 to 75°C) (for safe area products), conformally coated PCBs, and a backlit LCD that can be read in bright sunlight or dimly lit areas. Finally, there are intrinsically safe and nonincendive versions of these instruments that can be installed in hazardous areas.

Free, PC-based, software that connects to the meter via a micro USB cable is available for programming and setup of the meters. In addition, the meter can be programmed, setup and operated via the four front panel buttons. Three of these buttons can be used as function keys. In addition, a digital input is standard and is particularly useful for remote reset of the alarms or to trigger an alarm.

All models come equipped with two open collector outputs and are available with two solid state relays and 4-20 mA analog output options. The open collector outputs are useful for alarm indication or pulse output. The relays can be programmed for alarm indication, on/off control, or pump alternation.


  • 4-20 mA Input
  • Loop-Powered Process Meter
  • 1.5 Volt Drop (4.7 Volt Drop with Backlight)
  • Loop-Powered Backlight with Red Backlight for Alarm Conditions
  • NEMA 4X, IP65 Front
  • -40 to 167°F (-40 to 75°C) Safe Area Operating Temperature Range
  • Free PC-Based USB Programming Software
  • 5-Digit Alphanumeric Top Line
  • 8-Digit Alphanumeric Bottom Line
  • Displays Level in Feet & Inches up to 999 Feet, 11 & 15/16 Inches
  • 20-Segment Bargraph with Numeric Percent Indication
  • Conformal Coated PCBs for Dust & Humidity Protection
  • Two Open Collector Outputs Standard
  • Optional Loop-Powered Solid State Relays
  • Optional 4-20 mA Analog Output
  • Relay Pump Alternation Based on Level and Runtime
  • Display Relay Runtime and Cycle Count
  • UL & C-UL 61010 Listed for Electrical Safety
  • UL & C-UL Listed as Intrinsically Safe and Nonincendive
  • ATEX and IECEx Certified as Intrinsically Safe

PD6603 Feet and Inches Level Meter with Bargraph

PD6603 Feet and Inches Level Meter with Bargraph

Bargraph Provides Quick Understanding

To help users get a quick understanding of where their process is at, certain Loop Leader models are available with a 20-segment bargraph. This bargraph also includes a numeric value of the percentage the bargraph represents. The bargraph can be programmed to represent the percent of PV1 or PV2 or it can be scaled to any range within the scale.
PD6604 with Bargraph
Bargraph indicating a 200 gallon tank is just about full

Dual-Scale Display Feature

Users can use the Loop Leader’s dual-scale feature when they want to show the same input in two different scales. For instance, the following example shows an application where the Loop Leader displays the input in feet and gallons:
Display Feet & Gallons and Toggle Between Units
Loop Leader Meters Showing Dual Scale Feature


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


Input: 4-20 mA
Accuracy: ±0.02% of span ±1 count, Square root and programmable exponent: 10-100% FS
Voltage Drop: Without Backlight: 1.5 V maximum,
With backlight: 4.7 V maximum
Equivalent Resistance: With backlight off: 75 Ω @ 20 mA
With backlight on: 225 Ω @ 20 mA
Input Overload: Over current protection to 1 A maximum
Temperature Drift: 25 PPM/°C from -40 to 75°C ambient
Function: PV1: Linear, square root, or programmable exponent PV2: Linear or Round Horizontal Tank
Low-Flow Cutoff: 0.0 to 999,999.9
HART Transparency: Analog input will not interfere with existing HART communications on the wired 4-20 mA signal


Display: Dual-line LCD with backlight. Both lines 14-segment alphanumeric. Top: 0.7" (17.8 mm), Bottom: 0.4" (10.2 mm). Display may be programmed to turn red and flash a user-defined message on alarm condition.
Backlight: Powered by 4-20 mA loop. Intensity varies with signal level
PD6602 & PD6606:
Top line: 5 digits (-9999 to 99999) or 5 characters (all capital & most lower case letters)
Bottom line: 8 digits (-9,999,999 to 99,999,999; separated by commas) or 8 characters (all capital & most lower case letters)
Bargraph: None
PD6603 & PD6607:
Top line: -99FT 11IN 15/16 to 999FT 11IN 15/16
Bottom line: 8 digits (-9,999,999 to 99,999,999; separated by commas) or 8 characters (all capital & most lower case letters)
Bargraph: 20 segments, numeric percent indication at top
PD6604 & PD6608:
Top line: 5 digits (-9999 to 99999) or 5 characters (all capital & most lower case letters)
Bottom line: 8 digits (-9,999,999 to 99,999,999; separated by commas) or 8 characters (all capital & most lower case letters)
Bargraph: 20 segments, numeric percent indication at top
Decimal Point & Commas:
Top line: Up to four decimal places
Bottom line: Up to seven decimal places and commas to indicate 1000s (ie 88,987,628)
Dual-Scale Feature: The input can be displayed in different scales on the top and bottom lines. For instance, the top line could display the input in height and the bottom line could display that same input in volume.
Alarm Indication: Red backlight, flashing display, alarm symbol (!). Symbols are not available on bargraph models.
Alarm Message: On or Off; user programmable, 8 characters maximum. Displayed every 10 seconds for 1 second on bottom line.
Display Update Rate: Ambient > -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).
Overrange: Top: 99999; Bottom: 99,999,999 (flashing)
Underrange: Top: -9999; Bottom: -9,999,999 (flashing)


Environmental: Operating temperature range:
-40 to 75°C for safe area products
-40 to 70°C for hazardous area products
Storage temperature range: -40 to 85°C
Relative humidity: 0 to 90% non-condensing. Printed circuit boards are conformally coated.
Programming Method: Front panel & Free PC-based USB programming software
Enclosure & Materials: Enclosure: 1/8 DIN, IP65, NEMA 4X front panel, high impact plastic, NORYL® polyphenylene ether & polystyrene blend (PPE PS) resin, UL 94V-0, Color: gray, Gasket: silicone rubber, Faceplate: LEXAN® polycarbonate (PC) film, Buttons: silicone rubber
Noise Filter: Averages the input signal over a period of time between 1 and 16 seconds to dampen the effects of a noisy signal that causes a jumpy display.
Recalibration: Recalibration is recommended at least every 12 months.
Max/Min Display: Max/min readings reached by the process are stored until reset by the user or until power to the meter is turned off.
Tare: Zeros out display
Password: Programmable password restricts modification of programmed settings.
Non-Volatile Memory: All programmed settings are stored in nonvolatile memory for a minimum of ten years if power is lost.
Normal Mode Rejection: 64 dB at 50/60 Hz
Connections: Removable screw terminals accept 12 to 22 AWG wire.
DI Digital Input Contacts: 2.1 VDC on contact. Connect normally open contacts across DI+ and DI
DI Digital Input Logic Levels: Logic High: 2.4 to 30 VDC (max)
Logic Low: 0 to 0.9 VDC
Tightening Torque: Screw terminal connectors: 4.5 lb-in (0.5 Nm)
Mounting screws: 8.0 lb-in max. (0.9 Nm)
Overall Dimensions: 4.68"x 2.45"x 3.79" (119 mm x 62 mm x 96 mm) (W x H x D)
Weight: 8.7 oz (247g) with option board
Warranty: 3 years parts and labor

Common Open Collector & Relay (Alarm) Specifications

High or Low Alarm: User programmable for high or low alarm
Alarm Deadband: 0-100% FS, user programmable
On & Off Time Delay: 0 to 9,999 seconds
Fail-Safe Operation: Independent for each open collector and relay
Alarm Operation: Automatic, Automatic with manual override, Latching (manual reset anytime), Latching with reset after cleared (manual reset only after alarm has cleared)
Alarm Indication: Red backlight, flashing display, alarm symbol (!); (symbols not available on bargraph models)
Alarm Message: On or Off; User programmable, 8 characters maximum. Displayed every 10 seconds for 1 second on bottom line
Alarm Acknowledge: Front panel ACK button or external digital input resets output and screen indication
Auto Initialization: When power is applied to the meter, open collectors and relays will reflect the state of the input to the meter
Timer Output: One-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)
Stopwatch: Output turns on when started and off when stopped

Open Collector Outputs

Rating: Two NPN, Isolated open collector, 30 VDC @ 150 mA max
Output Assignment: Pulse, Alarm, Timer, Stopwatch on/off, or Disable
Pulse Output Source: PV (PV1, PV2) or Test Frequency
Pulse Output Factor: 0.000001 to 999,999.9
Pulse Width: 0.5 ms @ 1 kHz; 500 ms @ 1 Hz; 50% duty cycle
Pulse Output Frequency: 1,000 Hz maximum
Quadrature Pulse Output: Available for Output 2 (90° behind Output 1)
Alarm Output Source: Assign to PV (PV1, PV2) or Digital Input

Solid State Relays

Rating: Resistive Load: 250 VAC/DC @ 1 A
Inductive Load: 75 VA @ 0.6 A, 250 VAC/DC max (Safe Area only)
Noise Suppression: Metal oxide varistors across outputs
Relay Assignment: Pump Alternation, Alarm, Timer, Stopwatch on/off, or Disable
Alarm Output Source: Assign to PV (PV1, PV2) or Digital Input
Pump Alternation: Relays will alternate with each pump cycle and alternation can be based on elapsed time. Pump alternation time can be programed for: 0 to 999:59 (hrs:min)
Relay (Pump) Runtime: Meter will keep track of how long each relay (pump) has operated and display this information
Relay (Pump) Cycles: Meter will keep track of how many times the relays (pumps) have cycled and display this information

4-20 mA Transmitter Output

Accuracy: ±0.05% FS ±0.001mA
Output Source: PV1, PV2, re-transmit; reverse scaling allowed
Scaling Range: 1.00 to 23.0 mA
Disable: High impedance state, less than 1 mA
Calibration: Factory calibrated 4.00 to 20.00 mA
Underrange: 1.0 mA, 3.5 mA, or 3.8 mA (If input < 3.5 mA), or Off; user selectable
Overrange: 20.5 mA, 20.8 mA, or 23.0 mA (If input > 20.5 mA), or Off; user selectable
Isolation: 500 V input-to-output
Temperature Drift: 0.5 μA/°C max from -40 to 75°C ambient
External Loop Power Supply: 7.0 VDC to 30.0 VDC maximum
Output Loop Resistance: 10-750 Ω @ 24 VDC; 100-1100 Ω @ 30 VDC

Mounting Dimensions

  1. Panel cutout required: 1.772" x 3.622" (45mm x 92mm)
  2. Panel thickness: 0.040 - 0.250" (1.0mm - 6.4mm)
  3. Mounting brackets lock in place for easy mounting
  4. Clearance: Allow 6" (152 mm) behind the panel


Pump Alternation

The following is an example application where relays 1 & 2 are programmed for pump alternation. Below, the graphics provide a visual representation of a typical pump alternation application:

Signal Input Conditioning

The PD6600 Loop Leader process meter allows you to select the signal input conditioner applied to the input: linear, square root, programmable exponent, or round horizontal tank volume calculation.

The programmable exponent function is used to linearize the level signal in open channel flow applications using weirs and flumes and display flow rate in engineering units.
The square root function can be used to linearize the signal from a differential pressure transmitter and display flow rate in engineering units.
The round horizontal tank linearization function automatically calculates the volume in a round horizontal tank with flat ends.

Digital Input

A digital input comes standard on the Loop Leader PD6600 Series. This allows the user to program an external button to activate certain functions immediately like alarm acknowledgement, display minimum/maximum values, tare the display, reset a value, and many more. This allows the Loop Leader to be greatly customized for use in specialized applications. See the PD6600 series manuals for all digital input functions.


Connectors Labeling

The connectors' label, affixed to the meter, shows the location of all connectors available with requested configuration.

Current Loop (4-20 mA) Connections

The following figures show a 4-20 mA current loop connected to the meter. The first figure shows the connection with the backlight disabled and the second shows the connection with the backlight enabled. The meter is powered by the 4-20 mA current loop.

Digital Input Connection

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+.

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.

Relay Connections

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

Open Collector Outputs

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.

Free Meterview XL PC-Based Programming Software

PD6622/6 Loop-Powered Rate/TotalizerPD6624/8 Loop-Powered Rate/Totalizer with Bargraph
The main screen displays an image of the connected meter and includes various information about this meter, such as model number, readings, and status.

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.

  • Free
  • Easiest Way to Program Your Loop Leader
  • Convenient USB Connection
  • Meter Powered by USB Connection During Programming
  • Save & Print Configuration Files without Meter Connected
  • Micro USB Cable Provided

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Why you should buy:

  • Loop-Powered
  • Bargraph or Feet & Inches Display Options
  • Open Collector Outputs Standard
  • Solid State Relays Option
  • 4-20 mA Output Option