UL Approval Canadian Standards Association Atmosphères ExplosiblesEuropean ConformityIECEx Approval


  • Fully-Approved Explosion-Proof Loop-Powered Process Meter
  • 4-20 mA Input
  • 1 Volt Drop (4 Volt Drop with Backlight)
  • 1.0" (25.4 mm) 3½ Digits LCD Display; -1000 to 1999
  • Display Mountable at 0°, 90°, 180°, & 270°
  • HART® Protocol Transparent
  • Loop-Powered Backlight
  • Operating Temperature Range: -40 to 75°C (-40 to 167°F)
  • Installation Temperature Range: -55 to 75°C (-67 to 167°F)
  • Zero & Span Potentiometer Adjustments for Easy Field Scaling
  • Conformal Coated PCBs for Dust and Humidity Protection
  • 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
  • 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 Threaded Conduit Openings
  • 2" U-Bolt Kits Available
  • Stainless Steel Tag 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.


PD6870 Front/Connections

Hazardous Area Loop-Powered Meter

The ProtEX-FarVu PD6870 is a rugged, explosion-proof, loop-powered meter with 1" display digits ideal for demanding applications in hazardous areas or in the harshest environmental conditions.

The ProtEX-FarVu carries all major approvals including:

  • 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

It is available in either an aluminum or stainless steel enclosure with ¾" or M20 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 is programmed using four easy to access front-mounted potentiometers.

The numeric display will read from -1000 to 1999 over a 2000 count user adjustable scaling span. The backlight feature lets you see the display under any lighting condition and is powered from the 4-20 mA loop with no additional power supply required. The backlight can be enabled or disabled via alternative wiring of the terminal block.

The enclosure is provided with two conduit openings. The built-in mounting flange on the enclosure makes it convenient for pipe or wall mounting.


Display3½ digit LCD 1" (25.4 mm);
-1000 to 1999
Display OrientationDisplay may be mounted at 90° increments up to 270° from default orientation.
Display Update Rate2.5 Updates/Second
BacklightWhite; Loop-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.
Display OverrangeDisplay reads 1 on the left most digit
Programming MethodFour (coarse and fine for zero and span) potentiometers accessed when the cover is removed.
RecalibrationRecalibration is recommended at least every 12 months.
Normal Mode Rejection60 dB rejection ratio
EnvironmentalOperating temperature range: -40 to 75°C
Storage temperature range: -55 to 75°C
Installation temperature range: -55 to 75°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. Two slotted flanges for wall mounting or NPS 1½" to 2½" or DN 40 to 65 mm pipe mounting.
Overall Dimensions5.25" x 5.65" x 4.80"
(133 x 144 x 122 mm)
(W x H x D)
WeightAluminum Models: 5.00 lbs (80 oz, 2.27 kg)
Stainless Steel Models: 8.7 lbs (139 oz, 3.95 kg)
Warranty3 years parts and labor. See Warranty Information and Terms & Conditions on www.predig.com for complete details.


Input4-20 mA
Accuracy±0.1% of full span ±1 count
Maximum Voltage Drop & Equivalent ResistanceWithout BacklightWith Loop Powered Backlight
1 VDC @ 20 mA4 VDC @ 20 mA
50 Ω @ 20 mA200 Ω @ 20 mA
Temperature Drift150 PPM/°C from -40 to 75°C ambient
Decimal PointUser selectable decimal point
Calibration Range4 mA input: -1000 to +1000;
20 mA between 20 and 2000 counts greater than 4 mA display.
Two point linear display span.
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.


MaterialPD6870: ASTM A413 LM6 die-cast aluminum, copper-free, enamel coated
PD6870-SS: ASTM A743 CF8M investment-cast 316 stainless steel
Gasket (O-Ring)Fluoroelastomer
RatingNEMA 4X, IP68 Explosion-proof
ColorAluminum Models: Blue
Stainless Steel Models: Silver
WindowBorosilicate glass
ConduitsPD6870-0K0: Two 3/4" NPT
PD6870-0K0-M20: Two M20
PD6870-0K0-SS: Two 3/4" NPT
PD6870-0K0-SS-M20: Two M20
FlangesBuilt-in flange for wall and pipe mounting.
Tamper-Proof SealBase and cover can be secured with wire and lead seal

Product Ratings & 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
ATEXExplosion-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
      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


PD6870 Dimensions - Front
PD6870 Dimensions - Side
PD663 Dimensions - Top
PD6870 CAD Drawings


PD6870 Connector Labeling

Wiring Diagrams

For existing applications, one of the great benefits of loop-powered meters is that they get their power directly from the 4-20 mA loop and thus require no additional wiring. All a user has to do is break the existing loop and wire in the meter.

PD6870 Connections with Backlight

4-20 mA Input Connection with Backlight

PD6870 Connections without Backlight

4-20 mA Input Connection without Backlight


Choose Your Options