Martel Electronics DPM342 User Manual

DPM 342 LED Backlit 4-20mA Loop Powered Indicator

A compact loop powered indicator giving an accurate, zero corrected indication of 4-20mA loop current. Calibration is by two multi-turn
potentiometers which allow sensitive adjustment of the instrument. The DPM 342 features an integral snap-in bezel, making installation
easy. The module’s LED backlighting ensures a clear display, even under low light conditions. No soldering is required. Connection to the
current loop is via two screw terminals. The correct decimalpoint is selectedvia ajumper link.

11mm (0.43“) Digit Height

Programmable Decimal Points

Low Volt Drop

Loop Powered

LED Backlighting

Simple Screw Terminal Connections

Wide Adjustment Range

Auto-polarity on Display

Stock Number

Standard Meter DPM 342

Specification Min. Typ. Max. Unit

Accuracy (overall error) * 0.05 0.1 %(±1 count)
Linearity ±1 count
Sample rate 3 samples/sec
Operating temperature range 0 50 °C
Temperature s 200 ppm/°C
Loop Volt Drop 5 5.6 6 V
Supply current 4 mA
Full scale reading (20mA) 0 1999 Count
Offset adjustment range -950 +950 Count

*To ensure maximum accuracy, re-calibrate periodically.

tability

+ (span x 0.25)

CONNECTOR SOURCING GUIDE

METHOD Screw Terminals - No Connector Required

DIMENSIONS All dimensions in mm (inches)

40.0 (1.57)

27.3 (1.07)

12.7 (0.50)

20.0 (0.79)

17.5 (0.69)

37.5 (1.48)

abc

d

a. 2.00 (0.08)
b. 6.00 (0.24)
c. 1.60 (0.06) max
d. 9.50 (0.37)

DP3

DP2

Panel cut-out

38.0 x 18.0 (1.50 x 0.71)

Panel thickness

1.0 to 2.5 (0.04 to 0.1)

REAR VIEW

LK1

CAL

DP1

ON BOARD JUMPER LINKS

OFF

+-+ -

Calibration potentiometers

Martel Electronics, Corp. P.O. Box 770 Londonderry, NH 03053
Toll Free: [phone] Phone: [phone] Fax: [phone]

TERMINAL FUNCTIONS

1. + Positivecurrent input.

-

2. Negative current input.

CALIBRATION

The meteris suppliedcalibrated toread 000 for 4mA loop current and 1000for 20mA. C because theDPM 342
has a very wide adjustment range . Place the jumper link across LK1. This disables the offset adjustment to enable span adjustment to be made first.
After span adjustment is complete, the jumper link is removed and the offset adjustment is made. The jumper link is then used to display one of the
decimal points ifnecessary.

Example to re-calibrate:Meter toread -40.0for 4mA and150.0 for20mA.

1. Calculate thespan bysubtracting thedesired reading at4mA fromthe desiredreading at 20mA: -1500- (-400)= 1900

2. Short jumperlink Lk1with thelink header normallyused to selectthe desiredDecimal Point.
Link Lk1 islocated abovethe screwterminals.

3. Apply 16mAbetween the+ and- screw terminals.

4. Adjust the CALpotentiometer sothe DPM342 indicates 1900.

5. Remove jumperlink Lk1and placeit back onthe desiredDecimal Point (DP1 inthis case).

6. Apply 4mAbetween

7. Adjust the OFFpotentiometer so theDPM 342indicates thedesired reading at4mA: -40.0

8. Adjust CAL andOFF asnecessary for optimumaccuracy, by repeatingsteps 2to 7.

the - and+ screwterminals.

alibration iscarried out in two simple stages

SAFETY

The usermust ensurethat theincorporation ofthe DPMinto theuser’s equipmentconforms to the relevant sections of BS EN61010 (SafetyRequirements for
Electrical Equipment forMeasuring, Controland Laboratory Use). No inputsother than 4-20mAindicating loopcurrent shouldbe made.

JUMPER LINKS:

required Decimal Point, themeter has several on-boardjumper links.

DP3

DP2

DP1

PANELFITTING

In order to quickly and easily select the

DP3

DP2

DP1

Locate the meter by passing it through the front of the panel cut-out and gently push until the rear of the bezel is flush with
the panel (DO NOT PUSH ON THE LCD). The snap-in lugs will now automatically hold the meter firmly in position. Take
care when inserting the meter, not to damage the current loop wires and not to short them on the panel.

DP3

DP2

DP1

CURRENT LOOP CONNECTION:

its backlighting are powered from the 4-20mA signal loop and need no
other power supply. Ensure correct polaritywhen connecting.

I+

4-20mA

Transmitter

Connecting the DPM 342 to a 4-20mA Current Loop.

I-

+

-

The DPM 342 and

DPM 342

Specifications liable to change without prior warning DPM 342 Issue 2 July/2001 S.P.W. Applies to DPM 342/1