Martel Electronics DPM125 User Manual

DPM 125 3½ Digit LCD Module

This compact LCD DPM is ideally suited for low or high volume applications. It features an exceptionally large display in a miniature
package. The meter will plug directly into a SIL socket or can be panel mounted using the snap in bezel provided. The low profile bezel
incorporates a flatreverse printed windowgiving a superbappearance that cannotbe damaged orrubbed of bycontact.

12.5mm (0.5“) Digit Height

Logic Selectable Decimal Points

Auto-zero

Auto-polarity

200mV d.c Full Scale Reading (F.S.R.)

Low Battery Indication

SCALING

Two resistorsmay beused to alter the full scalereading of
the meter -seetable.
Note that the meter will have to be re-calibrated by
adjusting the calibrationpot.

+

INPUT

Ra

Rb

-

Required F.S.R. Ra Rb

2V 910k 100k
20V 1M 10k
200V 1M 1k
2kV Note 10M 1k
200 A 0R 1k

µ

2mA 0R 100R
20mA 0R 10R
200mA 0R 1R

NOTE

Ensure Ra is rated for high voltage use.

IN HI (7)

IN LO (8)

+

-

Stock Number

Standard Meter DPM 125

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 stability 100 ppm/°C
Supply voltage (V+ to V-) 7.5 9 14 V
Supply current 150 A
Input leakage current (Vin = 0V) 1 10 pA

* To ensure maximum accuracy, re-calibrate periodically.

µ

DIMENSIONS All dimensions in mm (inches)

48 (1.89)

24 (0.94)

40.5 (1.59)

38.0 (1.50)

f

20.4 (0.80)

ROH

RHI

RLO

COM

IN LO

12

ghi

IN HIV+V-

TEST

DP3

DP2

DP1

1

18.2 (0.72)

ab

d

c

a. 1.50 (0.06)

31.0 (1.22)

14.0 (0.55)

Viewing Area showing
display in TEST mode

REAR VIEW

4

1

3

e

12

2

9

DP3 DP2 DP1

11

1

b. 9.00 (0.35)
c. 5.00 (0.20)
d. 1.60 (0.06)
e. 4.00 (0.16)

f. 10.4 (0.41)
g. 7.50 (0.30)
h. 2.54 (0.10)

i. 0.50 (0.02)

Panel cut-out
45 x 22.2 (1.77 x 0.87)

ON BOARD SOLDER LINKS

PANELFITTING

Fit the bezel to the front of the panel and then locate the meter into the bezel from behind. Alternatively the meter and bezel may be assembled
before fitting into the front of the panel but care must be taken not to use excessive force. Finally fit the window into the front of the bezel.

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

PIN FUNCTIONS

1. DP1 199.9

2. DP2 19.99 Connect to V+ todisplay requiredDP.

3. DP3 1.999

4. TEST Connect to V+ todisplay segmentsas illustrated. It shouldnotbe operated for morethan afew secondsasthe d.c. voltage applied
to the LCD may'burn' thedisplay. This pin is normallyat5V below V+ andis theground forthedigital section of themeter.Itcan be
used to power external logic upto amaximum of1mA.

5. V- Negativepowersupply connection.

6. V+ Positivepower supplyconnection.

7. IN HI Positive measuringdifferential input.

8. INLO Negative measuring differential input.

Analogue inputs must beno closerthan 1Vtoeither the positive ornegative supply.

9. COM The ground for theanalogue sectionof theA/Dconverter, held actively at2.8V (nom.)below V+. COM mustnotbe allowed to sink
excessivecurrent (>100 A) byconnecting itdirectly toahigher voltage.

µ

10. RLO Negative input for referencevoltage (canbe connectedtoCOM via Link 3).

11. RHI Positive input for referencevoltage (connectedvia Link1to ROH).

12. ROH Positiveoutputfrom internal reference.

SAFETY

To comply with the Low Voltage Directive (LVD 93/68/EEC), input voltages to the module’s pins must not exceed 60Vdc. If voltages to the
measuring inputs do exceed 60Vdc, then fit scaling resistors externally to the module. The user must ensure that the incorporation of the
DPM into the user’s equipment conforms to the relevant sections of BS EN 61010 (Safety Requirements for Electrical Equipment for
Measuring, Control andLaboratory Use).

VARIOUS OPERATING MODES

ON-BOARD LINKS: In order to quickly and easily change operating modes for
different applications, the meter has several on-board links. They are designed
to be easily cut (opened) or shorted (soldered).
Do not connect more than one meter to the same power supply if the meters cannot
use the same signal ground. Taking any input beyond the power supply rails will
damage the meter.

7

±200mV

+

8

-

Check Links 2 & 3 are SHORTED.

Measuring a floating voltage source
of 200mV full scale.

+

-

Check Links 2 & 3 are SHORTED.

Measuring current. Supply MUST
be isolated.

IN HI

IN LO

--

R

R=0.2

IF.S.R.

V+

V-

V+

6

±200mV

0V

5

V-

Check Link 3 is SHORTED.

+

-

1V
min.

7

8

V+

IN HI

IN LO

6

V+

V-

5

V-

Split supply operation.

7

8

IN HI

IN LO

V+

6

V+

V-

5

V-

Check Links 1 & 4 are OPEN.

7

+

V

1

8

-

11

+

2

V

10

-

IN HI

IN LO

REF HI

REF LO

V+

V-

V+

6

5

V-

Measuring the ratio of two voltages.
Reading = 1000 V /V

50mV< V <200mV
V <2V .

12

12

2

14V max
7V min

Normally
SHORTED
Cut to
OPEN

V+

6

510K

V+

7

IN HI

SUPPLY
VOLTAGE

Check Link 3 is SHORTED.

10K

510K

8

IN LO

V-

5

Measuring a supply voltage.

(min. 7.5V, max. 14V).

IIN

100K

6R2

SET

5K

ZERO

IOUT

Check Link 3 is SHORTED.

7

8

9

IN HI

IN LO

COM

6

V+

V-

5

Measuring 4-20mA to read 0-999.
(supply MUST be isolated).

Normally
OPEN
Solder to
SHORT

V-

V+

V-

Specifications liable to change without prior warning DPM 125 Issue 3 August/1997 M.C. Applies to DPM 125/2