PD6626 (Alarm Condition)
PD6626 (Alarm Condition)
UL ListingAtmosphères ExplosiblesEuropean Conformity

These instrinsically safe and nonincendive, loop-powered 1/8 DIN flow rate/totalizers can be installed virtually anywhere to provide convenient and informative displays of flow rate and total from a 4-20 mA signal. One of the most convenient features of these instruments is their ability to display both flow rate and total at the same time. For instance, flow rate is typically displayed on the 5-digit alphanumeric top line and flow total or grand total is typically displayed on the 8-digit alphanumeric bottom line.

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 PD6624/6 that also includes a numeric value of the percentage the bargraph represents.

These flow rate/totalizers 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 158°F (-40 to 70°C), conformally coated PCBs, and a backlit LCD that can be read in bright sunlight or dimly lit areas. Finally, they are intrinsically safe and nonincendive, so they 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 total or to start/stop a timer/batch.

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 sending a pulse to indicate when a certain amount of total has been accumulated. The relays can be programmed for alarm indication, on/off control, sample taking, or simple batch control.


  • 4-20 mA Input
  • Loop-Powered Flow Rate/Totalizer
  • 1.5 Volt Drop (4.7 Volt Drop with Backlight)
  • Display Rate & Total Simultaneously
  • Loop-Powered Backlight with Red Backlight for Alarm Conditions
  • NEMA 4X, IP65 Front
  • -40 to 158°F (-40 to 70°C) Operating Temperature Range
  • Free PC-Based USB Programming Software
  • 5-Digit Alphanumeric Top Line
  • 8-Digit Alphanumeric Bottom Line
  • 8-Digit Total & Grand Total Display, Up to 13 Digits Using Both Lines
  • 20-Segment Bargraph with Numeric Percent Indication
  • Conformal Coated PCBs for Dust & Humidity Protection
  • Two Open Collector Outputs Standard
  • Dual-Line Display
  • 1/8 DIN Shallow Depth Case
  • Optional Loop-Powered Solid State Relays
  • Optional 4-20 mA Analog Output
  • UL & C-UL 61010 Listed for Electrical Safety
  • UL & C-UL Listed as Intrinsically Safe and Nonincendive
  • ATEX and IECEx Certified as Intrinsically Safe


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: Linear, square root, or programmable exponent
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
PD6622 & PD6626:
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)
PD6624 & PD6628:
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 (i.e. 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 flow in GPM and the bottom line could display that same input in CFM.
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.
Password: There are three password types available: 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 Memory: All programmed settings and total and grand total values are stored in non-volatile 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.
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


Rate Display Capability: Top display: -9999 to 99999; bottom display: -9,999,999 to 99,999,999 (with commas)
Total Display Capability: Top display: -9999 to 99999; bottom display -9,999,999 to 99,999,999 (with commas)
Grand Total Display Capability: Top display: N/A; bottom display -9,999,999 to 99,999,999 (with commas)
13-Digit Total & Grand Total Capability: Up to 9,999,999,999,999 using both lines with 13-digit total feature enabled.
Total & Grand Total Indication: On bottom display; "T" indicates total and "GT" indicates grand total. (not available on bargraph models)
Total Decimal Point: Up to four decimal places on top, up to seven decimal places on bottom. Total decimal point is independent of rate decimal point.
Totalizer: Calculates total based on rate and rate units to display total in engineering units. A custom factor must be programmed if using custom defined units.
Time Base: Seconds, Minutes, Hours, Days
Totalizer Rollover: Totalizer 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 Reset: Via front panel button or external contact closure on digital input
Total & Grand Total Reset Passwords: Total and grand total passwords may be entered to prevent resetting the total or grand total unless a password is entered.
Non-Resettable Grand Total: Grand 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

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, Total Reset, Stopwatch on/off, or Disable
Pulse Output Source: Rate, Total, Grand Total, 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 Rate, Total, Grand Total 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: Alarm, Sample, Timer, Batch, Stopwatch on/off, or Disable
Alarm Output Source: Assign to Rate, Total, Grand Total, or Digital Input

4-20 mA Transmitter Output

Accuracy: ±0.05% FS ±0.001mA
Output Source: Rate, total, 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

Batch Control

Methods: Automatic or Manual, count up or count down
Manual Batch Start: Pressing F1 function key starts the batch
Manual Batch Pause/Stop: Pressing F3 once pauses the batch, pressing it twice cancels the batch
Automatic Batching: The Loop Leader can be used as an automatic batch controller where batches run continuously without operator input.
Batching Relay Operation: Single or dual-relay batching with optional preclose for dual-stage operation
Batch Preset: Set 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 Preclose: For two-stage batch application, a preclose value can be set to close the main flow line.
Automatic Batch Restart Delay: 1 to 9,999 seconds. The batch will automatically restart after completion of the last batch.

Hazardous Area Approvals

ATEX: II 1G, Ex ia IIC T4 Ga, Ta = -40°C to +70°C
    Certificate number: CML 17ATEX2015X
IECEx: Ex ia IIC T4 Ga, Tamb = -40°C to +70°C
    Certificate number: IECEx CML 17.0008X
UL & C-UL Listed as Intrinsically Safe and Nonincendive:
    Class I, Division 1, Groups A, B, C and D T4,
    Class I, Division 2, Groups A, B, C and D T4
    Ex ia IIC T4 (Canada); Class I Zone 0, Zone 1
    AEx ia IIC T4 (U.S.), Class I Zone 2, IIC T4 (U.S.)

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


Open Channel Flow

The PD6622/24, in combination with an ultrasonic level transmitter, makes for an economical way to measure and display open channel flow rate and total in most weirs and flumes and take periodic samples.

Differential Pressure Flow

The PD6622/24 can display flow rate and total by extracting the square root from the 4-20 mA signal from a differential pressure transmitter. The user selectable low-flow cutoff feature gives a reading of zero when the flow rate drops below a user selectable value.

  • Display Flow Rate
  • User Selectable Low-Flow Cutoff
  • Only 2 Calibration Points Required

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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