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Precision Digital PD685 3½ Digit NEMA 4x Loop-Powered Meters

3½ Digit NEMA 4x Loop-Powered Meters

Only a calibrated current source and a screwdriver are needed for calibration.

Calibration Connections - To access the input terminals it is necessary to remove the enclosure cover and the Display PCB. This is done by loosening the four screws on the enclosure cover and removing the cover. Completely loosen the left screw that holds the Display PCB to the enclosure and loosen the right screw about four turns so the Display PCB remains attached to the enclosure. Rotate the Display PCB 90° to gain access to the Input Signal PCB. Next, connect a calibrated current source as illustrated in Figure 1.

Decimal Point Selection - The decimal point jumper array is located in the lower right corner of the Display PCB next to the display. It is labeled DP1, DP2, DP3. Place a jumper over both pins of DP1 for a display of 199.9, DP2 for 19.99, or DP3 for 1.999.

Calibration - LO and HI calibration controls are located to the left of the display. Apply a signal equal to 4 mA and adjust the LO control to display the desired reading. Apply a signal between 16 and 20 mA and adjust the HI control to display the desired reading. Complete the calibration procedure by making any minor adjustments to the LO and HI controls.

Installation - Installation of the meter involves removing the Display PCB from its enclosure and connecting a conduit fitting. Use conduit and fittings (not included) suitable for the degree of ingress protection required. Mounting holes are located at each corner of the enclosure.

Loop Connections - Disconnect power to the loop and install the meter. Replace the enclosure cover.

Removing Display PCB From the Loop - The Display PCB and Input Signal PCB are connected together with one black and one red wire. The wires are soldered to the Display PCB and connected to a screw terminal connector on the Input Signal PCB. To remove Display PCB:
  1. Loosen the four screws on the enclosure cover and remove the cover from the enclosure base.
  2. Completely loosen the left-side screw holding the Display PCB to the enclosure. Loosen the right-side screw four turns so the Display PCB remains secure to the enclosure.
  3. Rotate the Display PCB 90° to gain access to the Input Signal PCB.
  4. Install Loop Jumper over both pins to bypass Display PCB and allow the signal to flow through the Loop Jumper. The display will go off when the jumper is installed.
  5. Disconnect the black and red signal wires from the screw terminal connector.
  6. Loosen completely the right-side screw and lift Display PCB from the enclosure. Care should be taken to prevent static electricity from damaging the electronic circuitry.
  7. Restore enclosure cover to the base to prevent contamination of components.

Restoring Display PCB to the Loop
  1. Remove enclosure cover as described in step 1 in the preceding section.
  2. Secure Display PCB to enclosure using right-side screw; do not tighten screw to allow rotation of Display PCB while accessing Input Signal PCB.
  3. Connect red wire to S+ terminal and black wire to S- terminal, as shown in Figure 1.
  4. Remove Loop Jumper to allow the signal to flow through Display PCB (save push-on jumper by placing over one pin only).
  5. Tighten screws holding Display PCB and install enclosure cover.

• 1 V Drop
• 1 High Display
• Operates From -40 to 85°C

Select a link under the "item" tab below to order.

Cat #Descriptions½” Conduit Hole Location
PD6853½ Digit Loop-Powered MeterBottom
PD685-X3½ Digit Loop-Powered MeterRear
PD685-Y3½ Digit Loop-Powered MeterTop
PD685-Z3½ Digit Loop-Powered MeterNone
Input: 4-20 mA @ 30 VDC maximum
Display: 1.0" (25.4 mm) LCD, 3½ digits; 1999
Accuracy: ±0.1% FS ±1 count
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: -40 to 85°C
Storage Temperature: -40 to 85°C
Relative Humidity: 0 to 90% non-condensing
Enclosure: Impact-resistant plastic; body: gray ABS; cover: clear polycarbonate; NEMA 4X, IP66/67
Connections: Removable screw terminals accept 12 to 26 AWG
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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