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 3/4" 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.

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 / 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

Display	Five digits (-9999 to 99999)	0.70" (17.8 mm) high, 7-segment, automatic lead zero blanking.
	Seven characters	0.4" (10.2 mm) high, 14-segment.
	Symbols	High & Low Alarm, Password Lock
Display Orientation	Display may be mounted at 90° increments up to 270° from default orientation.
Display Assignment	Upper 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
Backlight	White; 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 Overrange	Display flashes 99999
Display Underrange	Display flashes -9999
Programming Method	Four SafeTouch through-glass buttons when cover is installed. Four internal pushbuttons when cover is removed.
Noise Filter	Programmable LO, med, HI, or OFF
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.
Advanced Function	Linear, square root, or programmable exponent
Password	Programmable password restricts modification of programmed settings.
Non-Volatile Memory	All programmed settings 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
Environmental	Operating 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
Connections	Screw terminals accept 12 to 22 AWG wire
Mounting	May 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 Dimensions	5.65" x 5.25" x 4.86" (W x H x D) (144 mm x 133 mm x 124 mm)
Weight	Aluminum: 4.8 lbs (2.18 kg) Stainless Steel: 8.7 lbs (4.3 kg)
Warranty	3 years parts and labor. See Warranty Information and Terms & Conditions on www.predig.com for complete details.

Input

Input	4-20 mA
Accuracy	±0.03% of calibrated span ±1 count, square root & programmable exponent accuracy range: 10-100% of calibrated span.
Temperature Drift	50 PPM/°C from -40 to 75°C ambient
Maximum Voltage Drop & Equivalent Resistance	Without Backlight or with Externally Powered Backlight	With Loop-Powered Backlight
	3.0 VDC @ 20 mA	6.0 VDC @ 20 mA
	150 Ω @ 20 mA	300 Ω @ 20 mA
Multi-Point Linearization	2 to 32 points
Signal Input Conditioning	Linear, square root, programmable exponent
Programmable Exponent	User selectable from 1.0001 to 2.9999 for open channel flow.
Low Flow Cutoff	0-99999 (0 disables cutoff function) Point below at which display always shows zero.
Decimal Point	User selectable decimal point
Minimum Span	Input 1 & Input 2: 0.10 mA
Calibration Range	An 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 Overload	Over current protection to 2 A max.
HART Transparency	The 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 Display	0 to 99,999 leading zero blanking
Total Display	0 to 9,999,999 leading zero blanking
Total Decimal Point	Up to six decimal places or none: d.dddddd, d.ddddd, d.dddd, d.ddd, d.dd, d.d, or ddddddd
Lower Display Configuration	Can be programmed to display total, tag name/engineering units, or to alternate between them.
Totalizer	Calculates 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 Reset	Via front panel SafeTouch button, time delay, external contact closure, or protected
Total Conversion Factor	0.000001 to 9,999,999
Totalizer Rollover	Display rolls over when display exceeds 9,999,999. Relay status reflects the displayed value.
Total Reset Delay	Programmable from 0 to 99,999 seconds

Open Collector Output

Rating	Isolated open collector, sinking NPN 30 VDC @ 150 mA max.
Alarm Output	Assign to rate for high or low alarm trip point. Assign to total for total alarm trip point.
Deadband	0-100% FS, user selectable
Acknowledge	Front 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 Frequency	Programmable 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

Material	AL 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
Rating	NEMA 4X, IP68 Explosion-proof
Color	AL: Blue SS: Silver
Window	Borosilicate glass
Conduits	PD6820-0K1: Two 3/4" NPT PD6820-0K1-M20: Two M20 PD6820-0K1-SS: Two 3/4" NPT PD6820-0K1-SS-M20: Two M20
Flanges	Built-in flange for wall and pipe mounting.
Tamper-Proof Seal	Cover may be secured with tamper-proof seal
Instrument Tag Loop	Built-in loop for securing stainless steel tag
ATEX & IECEx (ProtEX+ enclosure only)	Flame-Proof Protection II 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 (ProtEX+ 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 (ProtEX+ 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
ATEX	Explosion-Proof for use in: 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
IECEx	Explosion-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

Choose Your Options

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

Type A	Type B	Type C	Type D	Type E	Type F	Type G	Type H

PD690	PD542 PD543	PD603 PD644 PD743 PD765 PD6602 PD6603 PD6604 PD6606 PD6607 PD6608 PD6622 PD6624 PD6626 PD6628	PD138 PD154 PD158 PD520	PD6000 PD6001 PD6060 PD6080 PD6081 PD6088 PD6089 PD6100 PD6200 PD6210 PD6262 PD6300 PD6310 PD6363 PD6400 PD7000	PD530	PD510	PD420

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