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PD685 Intrinsically Safe IP67 Loop-Powered Meter

USA Toll Free: 1-800-730-0302 Tel: 416-240-1920 -

The PD685 is an ATEX and IECEx intrinsically safe, IP67 loop-powered indicator that is easy to install and program. It can be seen from considerable distance in bright sun or dimly lit areas when the standard backlight feature is activated. The fact that this meter is loop-powered means that there is no need to run additional, costly power lines into a hazardous area. The meter gets all of the power it needs from the 4-20 mA loop and its 1 V (4 V with backlight) drop results in a minimal burden on the loop. The meter features a wide -40°C to +75°C operating temperature range and is available with a 22 mm (0.865") conduit hole in a location of your choice for easy installation. Calibration is a quick two-step process involving the adjustment of only two sets of coarse and fine, non-interacting potentiometers.

PD663 Features

  • 4-20 mA Input
  • Loop-Powered Process Meter
  • 1 Volt Drop (4 Volt Drop with Backlight)
  • 28 mm (1.1 inch) 3½ Digits Display
  • Operates from -40°C to +75°C
  • Loop-Powered Backlight
  • Coarse and Fine Zero & Span Adjustments
  • IP67, NEMA 4X Enclosure
  • ATEX and IECEx Intrinsically Safe
  • CE Marked
  • Conformal Coated PCBs for Dust and Humidity Protection

PD685 Intrinsically Safe IP67 Loop-Powered Meter Instruction Manual

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

General Specifications

  • Input: 4-20 mA @ 30 VDC maximum
  • Display: 28 mm (1.1") LCD, 3½ digits; -1999 to +1999
  • Backlight: Powered by 4-20 mA loop. Intensity varies with signal level
  • Accuracy: ±0.1% FS ±1 count
  • Entity Parameters: Ui = 30 V, Ii = 175 mA, Pi = 1 W, Ci = 0, Li = 0
  • Decimal Point: User selectable via J2 jumper
  • Calibration: Four-step coarse and fine control; non-interacting zero and span
  • Calibration Range: 4 mA input: -1000 to +1000; 20 mA input: between 20 and 2000 counts > 4 mA display
  • Display Update Rate: 2.5/second
  • Maximum Input Current: 30 mA
  • Input Overload Protection: Over voltage protection to 30 V max (between S+ and S-)
  • Maximum Voltage Drop: 1 V @ 20 mA (4 V @ 20 mA with backlight)
  • Operating Temperature: -40°C to +75°C
  • Storage Temperature: -40°C to +85°C
  • Relative Humidity: 0 to 90% non-condensing. Printed circuit boards are conformally coated.
  • Enclosure: Impact-resistant, glass-filled, polycarbonate body, opaque; Impact-resistant, polycarbonate cover, transparent; Polyurethane/polymer gasket; Polyamide/plastic cover screws;
  • NEMA 4X, IP67
  • Connections: Removable screw terminal block, 12 to 24 AWG.
  • Conduit Hole: One 22 mm (0.865") conduit hole may be provided; refer to Ordering Information to specify conduit size and hole location; request model (-Z) for no conduit hole.
  • Weight: 340 g (12 oz)
  • Warranty: 2 years parts & labor

Compliance Information


Product Markings:


Ex ia IIC T4 Ga
Ex ia IIIC T135°C Da
-40°C = Ta = +75°C; IP67

Special Conditions for Safe Use:
1. The permitted ambient temperature range for the PD685 is -40°C to +75°C (-40°F to 167°F).
2. Use suitably certified and dimensioned cable entry device and/or plug. The equipment shall be installed such that the supply cable is protected from mechanical damage. The cable shall not be subjected to tension or torque.
3. Under certain extreme circumstances, the non-metallic parts incorporated in the enclosure of this equipment may generate an ignition-capable level of electrostatic charge. Therefore, the equipment shall not be installed in a location where the external conditions are conducive to the build-up of electrostatic charge on such surfaces. This is particularly important if the equipment is installed in a zone 0 location. In addition, the equipment shall only be cleaned with a damp cloth.
4. The cable entry into the enclosure shall be by means of conduit or cable gland and shall provide a minimum degree of protection of IP5X.

Year of Construction: This information is contained within the serial number with the first four digits representing the year and month in the YYMM format.
For European Community: The PD685 must be installed in accordance with the Essential Health & Safety Requirements of Directive 2014/34/EU, the product certificates CML 17ATEX2113X and IECEx CML 17.0052X, and the product manual. All controls and wiring connectors are accessed by opening the enclosure. To access electrical connectors, remove the enclosure cover, unscrew the two captive screws that fasten the printed circuit board, and remove the printed circuit board from the enclosure.


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Metex Corporation Limited has been providing superior products and services to the process control, chemical treatment, waste water, industrial and manufacturing industries for over 25 years. It is our goal to continually provide our customers with the best possible equipment, technology, and service.


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