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PD8-765 ProtEX-MAX Explosion-Proof Process and Temperature Meter

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The ProtEX-MAX PD8-765 explosion-proof, large-display, process and temperature meter offers all the functionality of the Trident X2 as a fully FM, CSA, ATEX, and IECEx approved explosion-proof product. PD8-765's huge 1.2" (30.5 mm) sunlight readable display that is visible from over 30 feet away. This explosion-proof indicator can be field programmed to accept process voltage (0-5 V, 1-5 V, etc.) and current (4-20 mA) inputs, 100 Ohm RTDs, and the four most common thermocouples. The intensity of the display can be adjusted to compensate for various lighting conditions, including direct sunlight. The meter can be programmed and operated without opening the housing by using the built-in SafeTouch® through-glass buttons or the RS485 serial communication port with free Modbus® protocol. Options for the PD8-765 process and temperature indicator include 2 relays, a 4-20 mA output, and a 24 V transmitter power supply.

Quick Overview

  • Input: Process: 0-20 mA , 4-20 mA; ±10 VDC (0-5, 1-5, 0-10 V)
  • Temperature: Thermocouple J, K, T, E; RTD 100 O Pt
  • Display: 4-digit, 1.20" (30.5 mm)
  • Enclosure: Smooth die-cast aluminum explosion-proof; NEMA 4X, 7, 9/IP6
  • Power: 85-265 VAC or 12-36 VDC option
  • Operating Temperature: -40 to 65°C


  • Sunlight readable display
  • Maximum/minimum display
  • Linear or square root with low-flow cutoff
  • Transmitter power option
  • SafeTouch® through-glass button programming
  • Modbus RS-485 serial communications
  • Flanges for wall or pipe mounting

PD8-765 ProtEX-MAX Explosion-Proof Process and Temperature Meter Data Sheet

PD8-765 ProtEX-MAX Explosion-Proof Process and Temperature Meter Instruction Manual

General Specifications

  • Display: 1.20” (30.5 mm) red LED, 4 digits (-1999 to 9999)
  • Display Intensity: Eight user selectable intensity levels
  • Programming Methods: Four SafeTouch through-glass buttons when cover is installed. Four internal pushbuttons when cover is removed.
  • Noise Filter: Programmable 2 to 199 (0 will disable filter)
  • Display Update Rate: Process/RTD: 3.7-5/sec; TC: 1.8-2.5/sec
  • Overrange: Display flashes 9999
  • Underrange: Display flashes -1999
  • Recalibration: All inputs are calibrated at the factory; recalibration is recommended at least every 12 months.
  • Max/Min Display: Stored until reset by user or meter is turned off.
  • Password: Restricts modification of programmed settings.
  • Non-Volatile Memory: Settings stored for a minimum of 10 years.
  • Power Options: 85-265 VAC, 50/60 Hz; 90-265 VDC, 20 W max or 12-36 VDC; 12-24 VAC, 6 W max.
  • Required Fuse: UL Recognized, 5 A max, slow-blow; up to 6 meters may share one fuse.
  • Normal Mode Rejection: 64 dB at 50/60 Hz
  • Isolation: 4 kV input/output-to-power line; 500 V input-to-output or output-to-24 VDC supplies.
    -6X5 models only: 100 V output-to-24 VDC supply
  • Environmental:
    T6 Class operating temperature range Ta = -40 to 60°C
    T5 Class operating temperature range Ta = -40 to 65°C
  • Connections:
    Power & Signal: removable screw terminal blocks accept 12 to 22 AWG.
    Serial: RJ11 header, standard on all meters.
  • Enclosure: Explosion-proof die cast aluminum with glass window, corrosion resistant epoxy coating, color: blue. NEMA 4X, 7, & 9, IP68. Default conduit connections: Four ¾" NPT threaded conduit openings and two ¾" NPT metal conduit plugs with 12 mm hex key fitting installed. Additional conduit opening configurations may be available; verify quantity and sizes on specific device labeling during installation.
  • Dimensions: 6.42" x 7.97" x 8.47" (W x H x D) (163 mm x 202 mm x 215 mm)
  • Weight: 16.0 lbs (7.26 kg)
  • Warranty: 3 years parts & labor

Process Inputs

  • Inputs: Field selectable: 0-20 mA, 4-20 mA, 1-5 V, ±10 V
  • Accuracy: ±0.05% FS ±1 count; square root: ±0.1% FS ±2 counts
  • Function: Linear or square root
  • Low-Flow Cutoff: 0 to 9999 (0 disables cutoff function)
  • Decimal Point: Up to 3 decimals: d.ddd, dd.dd, ddd.d, or dddd
  • Calibration: Scale without signal or calibrate with signal source
  • Calibration Range: User programmable over entire range of meter
  • Input Impedance: Voltage range: greater than 1 M O, Current Range: 50-100 O, varies with resettable fuse impedance
  • Input Overload: Protected by automatically resettable fuse
  • HART Transparency: Analog input will not interfere with existing HART communications on the wired 4-20 mA signal

Temperature Inputs

  • Inputs: Factory calibrated, field selectable: type J, K, T, or E thermocouples and 100 O platinum RTD (0.00385 or 0.00392 curve)
  • Resolution: 1°; type T: 1° or 0.1°
  • Cold Junction Reference: Automatic
  • Temperature Drift: ±2°C maximum
  • Offset Adjustment: Programmable to ±19.9°. This parameter allows the user to apply an offset value to the temperature being displayed.
  • Input Impedance: Greater than 100 k O
  • Sensor Break: All relays and alarm status LEDs go to alarm state.


  • Rating: 2 Form C (SPDT); rated 3 A @ 30 VDC or 3 A @ 250 VAC resistive load; 1/14 HP @ 125/250 VAC inductive loads
  • Deadband: 0-100% FS, user selectable
  • High or Low Alarm: User may program any alarm for high or low
  • Relay Operation:
    1.Automatic (non-latching)
    3.Pump alternation control
  • Relay Reset: User selectable via front panel buttons or PC
    1.Automatic reset only (non-latching)

    2.Automatic plus manual reset at any time (non-latching)
    3.Manual reset only, at any time (latching)
    4.Manual reset only after alarm condition has cleared (latching).

  • Automatic Reset: Relays reset when input passes the reset point

  • Manual Reset: Front panel button, MeterView, Modbus registers

  • Time Delay: 0 to 199 seconds, on and off delays; programmable

  • Fail-Safe Operation: Programmable, independent for each relay. Relay coils are energized in non-alarm condition. In case of power failure; relays will go to alarm state.

  • Auto Initialization: When power is applied to the meter, relays will reflect the state of the input to the meter.

Isolated 4-20 mA Transmitter Output

  • Scaling Range: 1.00 to 23.00 mA; reverse scaling allowed.
  • Calibration: Factory calibrated 4.00 to 20.00 mA
  • Accuracy: ±0.1% FS ±0.004 mA
  • Temperature Drift: 50 PPM/°C
    Note: Analog output drift is separate from input drift
  • Isolation: 500 V input-to-output or output-to-24 VDC supplies; 4 kV output-to-power line
  • External Power: 35 VDC maximum

Serial Communications

  • Compatability: EIA-485
  • Connectors: Removable screw terminal connector
  • Max Distance: 3,937' (1,200 m) max
  • Status Indication:Separate LEDs for Power (P), Transmit (TX), and Receive (RX)
  • Protocol: Two selectable. PDC protocol (for use with MeterView) and Modbus RTU
  • Meter Address: PDC protocol: 0 to 99, Modbus protocol: 1 to 247
  • Baud Rate: 300 to 19,200 bps
  • Transmit Time Delay: Programmable 0 to 199 ms or transmitter always on for RS-422 communications.
  • Data: 8 bit (1 start bit, 1 stop bit)
  • Parity: None (2 stop bits), even, or odd
    (Modbus only; PDC protocol does not use parity)
  • Byte-to-Byte Timeout: 0.01 to 2.54 seconds (Modbus only)
  • Turn Around Delay: Less than 2 ms (fixed)

External Switch Contacts

  • Open State: +5 VDC open contact on switch input terminals
  • Closed State: Closed contact switch input terminal to common/ground, active low 0 to 0.4 VDC, or open collector transistor activated input

Product Ratings and Approvals

  • FM Enclosure: Type 4X; IP66
    Class I, Division 1, Groups B, C, D
    Class II, Division 1, Groups E, F, G
    Class III, Division 1, T5/T6
    Class I, Zone 1, AEx d, IIC Gb T5/T6
    Zone 21, AEx tb IIIC T90°C; Ta -40°C to +65°C
    T6 Ta = -40°C to +60°C; T5 Ta = -40°C to +65°C
    Certificate Number: 3047283
  • CSA: Class I, Division 1, Groups B, C, D
    Class II, Division 1, Groups E, F, G
    Class III, Division 1
    Class I Zone 1 Ex d IIC
    Zone 21 Ex tb IIIC T90°C
    -40°C < Tamb. < +60° C; Temperature Code T6
    -40°C < Tamb. < +65° C; Temperature Code T5
    Enclosure Type 4X & IP66
    Certificate Number: 2531731
  • ATEX: II 2 G D Ex d IIC T* Gb
    Ex tb IIIC T90°C Db IP68
    Ta = -40°C to +*°C
    *T6 = -40°C to +60°C
    *T5 = -40°C to +65°C
    Certificate number: Sira 12ATEX1182
  • IECEx: Ex d IIC T* Gb
    Ex tb IIIC T90°C Db IP68
    Ta = -40°C to +*°C
    *T6 = -40°C to +60°C
    *T5 = -40°C to +65°C
    Certificate Number: IECEx SIR 12.0073

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