Precision Digital Corporation - Loop-Powered Meters

Precision Digital ISO 9001:2000 Certified Quality System

Setup	Calibration	Decimal Point Selection	Loop Connections

Dimensions	Specifications	Ordering Information	Documentation

Loop-Powered Indicator PD685

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

The PD685 is a low-cost, NEMA 4X, loop-powered indicator that is easy to install and program and can be seen from considerable distance. It will operate over a wide temperature range meaning it can be installed both indoors and out. And the PD685's 1 V drop results in a minimal burden on the loop. Calibration is a quick two-step process involving the adjustment of only two non-interacting potentiometers.

Note: For complete installation information see instruction manuals below

Setup

The only tools needed for calibration are a calibrated current source and a screwdriver.

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 per Figure 1 to the right.

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 leftof the display (see Figure 1). Apply a signal equal to4 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.

Loop-powered indicator Calibration Connections

Figure 1: Calibrator Connected to Input Signal PCB

Installation

Installation of the meter involves removing the Display PCB from its enclosure and connecting a ½" conduit fitting to the hole provided. Wall mounting holes are located in each corner of the enclosure (Figure 1 shown above).

Loop Connections

Loop-Powered Indicator PD686 FM Approved & CSA Certified Meter Intrinsic Safety Barrier Connections Diagrams

Figure 2: Control loop Connected to Input Signal PCB

Disconnect power to the loop and install the meter as illustrated in Figure 2 (shown to the left). Replace the enclosure cover.

Field wiring is made to the Input Signal PCB which is mounted to the base of the enclosure

Servicing Display PCB Outside the Loop

Two modes of input signal allow the user to remove the Display PCB for service without interrupting the loop as indicated above and operate the Display PCB at another location. The loop remains connected to the Input Signal PCB while the Display PCB is absent for service.

The user may operate the Display PCB at another location by connecting a signal to "S+" and "S-" wires on the Display PCB. Refer to Figure 3 to the right.

The Display PCB may be removed from the enclosure for bench calibration. Loop Jumper must be installed on Input Signal PCB to maintain loop.

Loop Powered Indicator PD686 FM Approved & CSA Certified Meter Display PCB Outside the Loop

Figure 3: Calibrator Connected to Display PCB

Dimensions and Wall Mounting Information

Loop-powered Indicator Dimensions and Mounting Spec for PD685

A: 3.15" (80 mm)	C: 2.36" (60 mm)	E: 2.56" (65 mm)
B: 5.51" (140 mm)	D: 4.72" (120 mm)	F: 0.79" (20 mm)

Figure 4

Specifications

General

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

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
Extended Warranty: 1 or 2 years

Disclaimer

The Information contained in this document is subject to change without notice. Precision Digital Corporation makes no representations or warranties with respect to the contents hereof, and specifically disclaims any implied warranties of merchantability or fitness for a particular purpose.

Ordering Information

Product Information
Model	Description	½" Hole Location	Price
PD685	General Purpose 3½ Digit Loop-Powered Meter	Bottom	$259
PD685-X	General Purpose 3½ Digit Loop-Powered Meter	Rear	$259
PD685-Y	General Purpose 3½ Digit Loop-Powered Meter	Top	$259
PD685-Z	General Purpose 3½ Digit Loop-Powered Meter	None	$259


Accessories
Model	Description		Price
PDA6844	Panel Mounting Kit (does not provide NEMA 4X seal to panel)		$49
PDA6845	Pipe Mounting Kit (zinc plated steel)		$49
PDA6845-SS	2" Pipe Mounting Kit (stainless steel)		$79
PDA-SSTAG	Stainless Steel Tag		$25

Services
Model	Description		Price
PDN-CAL	Calibration with Certificate		$50
PDN-CALDATA	Calibration With Certificate & Data		$75
PDN-EXTWRNTY1-0	Extended Warranty 1 Year Based on List Price: $0-299		$35
PDN-EXTWRNTY2-0	Extended Warranty 2 Years Based on List Price: $0-299		$50
PDN-LTCAL5	Lifetime Calibration with Annual Recert (shipped back within 5 days)

Documentation
The documentation can be downloaded from these links:

PD685: Instruction Manual

Mounting Kits for Precision Digital Meters

Setup and Calibration Services Order Form

Stainless Steel Tag Order Form

Extended Warranty Info

See How You can Use Precision Digital Products for

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