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PD686 Loop-Powered NEMA 4X Intrinsically Safe & Nonincendive Digital Meter

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

The PD686 is an Intrinsically Safe and Nonincendive, NEMA 4X, loop-powered indicator that is easy to install and program and can be seen from considerable distance. 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 the PD686's 1 V drop results in a minimal burden on the loop. The meter features FM and CSA approvals as Intrinsically Safe and Nonincendive, a wide -40 to 85°C operating temperature range, and is provided with a ½" conduit hole in a location of your choice for easy installation. Calibration is a quick two-step process involving the adjustment of only two non-interacting potentiometers.

PD666 Features

  • 4-20 mA Input
  • NEMA 4X
  • 1 V Drop
  • 3½ Digit LCD 1" (25.4 mm) High
  • Operating Temperature Range: -40 to 85°C
  • ½ Conduit Hole Provided
  • Intrinsically Safe with Entity Class I, II, III; Div. 1; Gp A, B, C, D, E, F, G
  • Non-incendive: Class I, II, III; Div2; Gp A, B, C, D, F, G

PD686 Loop-Powered NEMA 4X Intrinsically Safe & Nonincendive Digital Meter Instruction Manual

General Specifications

  • Input: 4-20 mA @ 30 VDC maximum
  • Display: 1.0" (25.4 mm) LCD, 3½ digits; 1999
  • Accuracy: ±0.1% FS ±1 count
  • Approvals: FM Approved & CSA Certified as intrinsically safe with entity, for use in Class I, II, III, Division 1, Groups A, B, C, D, E, F, & G; T-code = T4; hazardous locations. Non-incendive for use in Class I, II, III, Division 2, Groups A, B, C, D, F, & G.
  • Entity Parameters: Vmax= 30 V, Imax = 175 mA, Ci= 0 µF, Li = 0 µH, Pi = 1.3 W
  • FM Approved: Intrinsically Safe, Class I Zone 0
    Decimal Point: User selectable
  • Calibration: Two-step; 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
  • Maximum Voltage Drop: 1 V @ 20 mA
  • Operating Temperature: PD686: -40 to 85°C
    for Canadian installations -40 to 40°C.
  • Storage Temperature: -40 to 85°C
  • Relative Humidity: 0 to 90% non-condensing
  • Enclosure: Impact-resistant glass filled polycarbonate body, color: gray; impact-resistant clear polycarbonate cover; NEMA 4X, IP67
  • Connections: Removable screw terminals accept 12 to 26 AWG
  • HART Transparency: Analog input will not interfere with existing HART communications on the wired 4-20 mA signal
  • Conduit Hole: One ½" conduit hole provided; refer to Ordering Information to specify conduit hole location; request models with rear conduit hole (-X) for panel mounting applications.
  • Weight: 12 oz (340 g)
  • Warranty: 2 years parts & labor


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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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