Aluminum or Stainless Steel
Canadian Standards Association Atmosphères ExplosiblesEuropean ConformityIECEx Approval

Features

  • Fully-Approved Explosion-Proof Loop-Powered Rate/Totalizer
  • 4-20 mA Input with ±0.03% Accuracy
  • 3.0 Volt Drop (6.0 Volt Drop with Backlight)
  • Easy Field Scaling in Engineering Units without Applying an Input
  • 0.7" (17.8 mm) 5 Digits Main Display
  • 0.4" (10.2 mm) 7 Alphanumeric Characters Secondary Display for Total, Tag, or Units
  • Simultaneous 5-Digit Rate and 7-Digit Total Display
  • Rate in Units per Second, Minute, Hour, or Day
  • Display Open Channel Flow with Programmable Exponent Feature
  • Open Collector Pulse or Alarm Output
  • Display Mountable at 0°, 90°, 180°, & 270°
  • SafeTouch Through-Glass Button Programming
  • HART® Protocol Transparent
  • Loop or External DC-Powered Backlight Standard
  • Operating Temperature Range: -40 to 75°C (-40 to 167°F)
  • Installation Temperature Range: -55 to 75°C (-67 to 167°F)
  • CSA Certified as Explosion-Proof / Dust-Ignition-Proof / Flame-Proof
  • ATEX and IECEx Certified as Explosion-Proof
  • Conformal Coated PCBs for Dust and Humidity Protection
  • Password Protection for Programming Only
  • 32-Point Linearization, Square Root Extraction and Programmable Exponent Function
  • Wide Viewing Angle
  • Built-In Flange for Wall or Pipe Mounting
  • Explosion-Proof, IP68, NEMA 4X Die-Cast Aluminum & Stainless Steel Enclosures
  • Two 1/2" NPT or M20 Conduit Openings
  • 2" U-Bolt Kit Available
  • 3-Year Warranty

Why Use Loop-Powered Meters?

The most basic decision a user wishing to display a 4-20 mA signal on a digital display has to make is: should the meter be powered by line voltage or should it be powered by the 4-20 mA loop?

There are three main benefits of using loop-powered devices:

  • No additional power required
  • Easy wiring
  • Additional digital displays can easily be added in the same loop

The following diagram illustrates how a loop-powered meter is wired. Notice there are only two connections made to the meter.

Loop-Powered Connections

For more information on loop-powered meters, check out Fundamentals of Loop-Powered Devices and Loop-Powered vs Line-Powered Meters white papers.

Overview

Hazardous Area Loop-Powered Rate/Totalizer

The PD6820 is a rugged, full-featured, explosion-proof loop-powered flow rate/totalizer ideal for demanding applications in hazardous areas or in the harshest environmental conditions. The product is CSA Certified as Explosion-Proof, Dust-Ignition-Proof, and Flame-Proof, and ATEX & IECEx Certified as Explosion-Proof. It is available in either an aluminum or stainless steel enclosure with ¾" or M20 conduit connections. It will operate down to -40°C and is approved for installation in areas where the temperature gets as cold as -55°C, however, the display will cease functioning.

The meter derives all of its power from the 4-20 mA loop thus making installation a simple matter of wiring the instrument into the existing loop. No external power is required. Programming is performed using the four SafeTouch through-glass buttons and can be done without removing the cover. In addition, the meter can be scaled with or without a calibration signal.

The backlit LCD display consists of two lines. The top line of the display has five full digits and can display flow rate or total. The bottom line has seven alphanumeric characters and can display flow rate, total, grand total, a tag, or engineering units. The backlight makes the display visible under any lighting condition and can be powered from either the 4-20 mA loop or from a separate DC power supply. A pulse output is available that can be used to send a pulse to an external device for every user-specified amount of volume totalized.

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

General

DisplayFive digits
(-9999 to 99999)
0.70" (17.8 mm) high, 7-segment,
automatic lead zero blanking.
Seven characters0.4" (10.2 mm) high, 14-segment.
SymbolsHigh & Low Alarm, Password Lock
Display OrientationDisplay may be mounted at 90° increments up to 270° from default orientation.
Display AssignmentUpper display is assigned to rate and lower display may be assigned to total, tag name/ engineering units, or to alternate between them.
Display Update Rate

Ambient > -25°C: 2 Updates/Second
Ambient < -25°C: 1 Update/5 Seconds

BacklightWhite; Loop-powered or externally powered. Backlight can be enabled or disabled via alternative wiring of terminal block. Loop-powered backlight brightness will increase as the input signal current increases. Externally powered backlight has consistent brightness.
Externally Powered
Backlight
Voltage Range: 9-36 VDC
Supply V  9 VDC  12 VDC  24 VDC  36 VDC
Max Pwr  0.2 W  0.25 W  0.5 W  0.75 W
Display OverrangeDisplay flashes 99999
Display UnderrangeDisplay flashes -9999
Programming MethodFour SafeTouch through-glass buttons when cover is installed. Four internal pushbuttons when cover is removed.
Noise FilterProgrammable LO, med, HI, or OFF
RecalibrationRecalibration is recommended 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.
Advanced FunctionLinear, square root, or programmable exponent
PasswordProgrammable password restricts modification of programmed settings.
Non-Volatile MemoryAll programmed settings are stored in non-volatile memory for a minimum of ten years if power is lost.
Normal Mode Rejection64 dB at 50/60 Hz
EnvironmentalOperating temperature range: -40 to 75°C (-40 to 167°F)
Storage temperature range: -55 to 75°C (-67 to 167°F)
Installation temperature range: -55 to 75°C (-67 to 167°F)
(The display ceases to function below -40°C)
Relative humidity: 0 to 90% non-condensing
Printed circuit boards are conformally coated
ConnectionsScrew terminals accept 12 to 22 AWG wire
MountingMay be mounted directly to conduit. Built-in flange for wall mounting or NPS 1½" to 2½" or DN 40 to 65 mm pipe mounting.
Overall Dimensions5.65" x 5.25" x 4.86"
(W x H x D)
(144 mm x 133 mm x 124 mm)
WeightAluminum: 4.8 lbs (2.18 kg)
Stainless Steel: 8.7 lbs (4.3 kg)
Warranty3 years parts and labor. See Warranty Information and Terms & Conditions on www.predig.com for complete details.

Input

Input4-20 mA
Accuracy±0.03% of calibrated span ±1 count, square root & programmable exponent accuracy range: 10-100% of calibrated span.
Temperature Drift50 PPM/°C from -40 to 75°C ambient
Maximum Voltage Drop & Equivalent ResistanceWithout Backlight or with Externally Powered BacklightWith Loop-Powered Backlight
3.0 VDC @ 20 mA6.0 VDC @ 20 mA
150 Ω @ 20 mA300 Ω @ 20 mA
Multi-Point Linearization2 to 32 points
Signal Input ConditioningLinear, square root, programmable exponent
Programmable ExponentUser selectable from 1.0001 to 2.9999 for open channel flow.
Low Flow Cutoff0-99999 (0 disables cutoff function)
Point below at which display always shows zero.
Decimal PointUser selectable decimal point
Minimum SpanInput 1 & Input 2: 0.10 mA
Calibration RangeAn Error message will appear if input 1 and input 2 signals are too close together.
Input Range
4-20 mA
Minimum Span Input 1 & Input 2
0.10 mA
Input OverloadOver current protection to 2 A max.
HART TransparencyThe meter does not interfere with existing HART communications; it displays the 4 20 mA primary variable and it allows the HART communications to pass through without interruption.
The meter is not affected if a HART communicator is connected to the loop.
The meter does not display secondary HART variables.

Rate/Totalizer

Rate Display0 to 99,999 leading zero blanking
Total Display0 to 9,999,999 leading zero blanking
Total Decimal PointUp to six decimal places or none: d.dddddd, d.ddddd, d.dddd, d.ddd, d.dd, d.d, or ddddddd
Lower Display ConfigurationCan be programmed to display total, tag name/engineering units, or to alternate between them.
TotalizerCalculates total based on rate, time base of second, minute, hour, or day, and field programmable multiplier; stored in non-volatile memory upon power loss.
Totalizer ResetVia front panel SafeTouch button, time delay, external contact closure, or protected
Total Conversion Factor0.000001 to 9,999,999
Totalizer RolloverDisplay rolls over when display exceeds 9,999,999. Relay status reflects the displayed value.
Total Reset DelayProgrammable from 0 to 99,999 seconds

Open Collector Output

RatingIsolated open collector, sinking NPN 30 VDC @ 150 mA max.
Alarm OutputAssign to rate for high or low alarm trip point.
Assign to total for total alarm trip point.
Deadband0-100% FS, user selectable
AcknowledgeFront panel ACK button resets output and screen indication.
Pulse Output Scaler (Count)The pulse output scaler (count) is programmable from 0.0001 to 99999. One pulse is generated for every total increment selected (e.g. A pulse scaler value of 100 will generate one pulse every time the total is incremented by 100 units).
If the pulse output exceeds the programmed output frequency, pulses are accumulated as pending and are not lost. Pulses will continue to output until the buffer is emptied or the total is reset from the front panel.
Pulse Output FrequencyProgrammable frequency: 2, 4, 8, 16, 32, 64, 128 Hz.
Minimum pulse width: 3.9 ms @ 128 Hz
Maximum pulse width: 250 ms @ 2 Hz
Factory default pulse width: 31 ms @ 16 Hz

Enclosure

MaterialAL Models: ASTM A413 LM6 die-cast aluminum, copper-free, enamel coated
SS Models: ASTM A743 CF8M investment-cast 316 stainless steel
Gasket (O-Ring)Fluoroelastomer
RatingNEMA 4X, IP68 Explosion-proof
ColorAL: Blue
SS: Silver
WindowBorosilicate glass
ConduitsPD6820-0K1: Two 3/4" NPT
PD6820-0K1-M20: Two M20
PD6820-0K1-SS: Two 3/4" NPT
PD6820-0K1-SS-M20: Two M20
FlangesBuilt-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
ATEX & IECEx
(enclosure only)
Flameproof protection
ATEXII 2GD
Ex db IIC Gb
Ex tb IIIC Db
IP66/IP68
Tamb: -55°C to +85°C
Certificate No.: Sira 19ATEX1252U
Certificate No.: IECEx SIR 19.0075U
CSA
(enclosure only)
Class I, Division 1, Groups A, B, C, D
Class II, Division 1, Group E, F, G
Class III
Ex db IIC Gb
Ex tb IIIC Db
Class I, Zone 1, AEx db IIC Gb;
Zone 21, AEx tb IIIC Db
IP66/IP68/TYPE 4X
Tamb: -55°C to +85°C
Certificate Number: CSA 19.80011200U
UL
(enclosure only)
Class I, Division 1, Groups A, B, C, D
Class II, Division 1, Groups E, F, G
Class III;
Class I, Zone 1, AEx db IIC Gb
Zone 21, AEx tb IIIC
Ex db IIC Gb
Ex tb IIIC Db
IP66/IP68/TYPE 4X
Tamb: -55°C to +85°C
Certificate Number: E518920
Note: The above approvals are for the enclosure only. See below for approval on the entire instrument.

Product Ratings & Approvals

CSA
Explosion-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
ATEXExplosion-proof for use in:
ATEX Ex II 2 G D
Ex db IIC T6 Gb
Ex tb IIIC T85°C Db IP68
Ta = -55 to 75°C
Certificate Number: Sira 10ATEX1116X
IECExExplosion-proof for use in:
Ex db IIC T6 Gb
Ex tb IIIC T85°C Db IP68
Ta = -55 to 75°C
Certificate Number: IECEx SIR 10.0056X

Connections



Dimensions

Front View
Side View
Top View
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Choose Your Options

Configurations other than those specified above are available at a $250 adder. Consult factory for desired model number and price.