1. Decimal Point Placement: DATEL ships the DMS-EB with all decimal

point solder gaps (SG1, SG2, SG3 and SG17) open. To enable a specific

decimal point, close its respective solder gap with solder. When reas-

signing decimal places for subsequent applications, remember to

open previously closed solder gaps.

Close SG1 for 1.999 (DP1)

Close SG2 for 19.99 (DP2)

Close SG3 for 199.9 (DP3)

Close SG17 for 1999.9 (DP4 on DMS-40)

2. Display Test: Tie J1, pin 4 (TEST OUT) to pin 3 (TEST IN) to test the

display of the DMS-30. Do not leave the meter in the test mode for

more than 10 seconds. Display test is not available on backlit models.

3. Battery Operation: Open SG4 and install U1 (LM7805CT) with its

metal tab facing down as shown Figure 2. Allowable input power

ranges (J1, pins 5 and 6) are as follows:

DMS-30/40PC-X-XS

+7.5 to +12.6V

DMS-30/40PC-X-XL

+7.5 to +18.0V

DMS-30/40LCD-X-5

+7.5 to +32.0V

DMS-30/40LCD-X-5B

+7.5 to +12.6V

4. Differential Input Signals (Signal Referenced to Power Source):

Open SG5. Apply the input signal to pin 1, (+) IN HI, and pin 2, (–) IN

LO, of J1.

Note: Common mode voltage must not exceed ±2Vdc. Differential

signals are defined as inputs whose two terminals are both above and

below J1, pin 6 (GROUND).

5. Span (Gain) and Zero (Offset) Adjustments: Locations are included

on the DMS-EB to add user-supplied potentiometers R4 and R5, and

resistor R3. Recommended values for these components are as fol-

lows: R3: 10.5KΩ, 1%, 1/8W metal film; R4: 2KΩ, 10-20-turns; R5:

50KΩ, 10-20 turns. Vishay's T93YA series potentiometers are suitable

for this application. Make sure to use only RoHS-compliant compo-

nents and solders when making modifications to DMS-EB.

Once installed, these components permit the span and zero adjust-

ments described in the following sections. R3 and R4 provide span

adjust, while R5 applies and offset voltage to (-) IN LO (J1, pin 2).

Using Full Range Span Adjustment (DMS-30 Only)

5.1. For DMS-30-1 and -2 models: Configuring the DMS-EB for span

adjustment is simply a matter of installing resistor R3 and potenti-

ometer R4, opening SG13 and then closing SG8, SG11 and SG12.

5.2. For DMS-30-0 models: Span adjustment requires that you open

SG8, SG11 (if closed) and SG13 and then close SG7, SG9 and

SG12. Then install R3 and R4.

Adjust span as desired. DMS-30-1 and -2 span adjustment range

is typically +10% and –5%. The DMS-30-0 has a much wider span

adjust, however, it should be limited to ±10% for optimum accuracy.

6. Measuring Input Voltages Greater than 1.999Vdc (Use DMS-30-1

Only): If possible, the resistors used for R1 and R2 should be ±1%

metal-film types with TCR's less than 100ppm/°C. More information

on selecting 1% resistors can be found in Application Note 14.

CAUTION: Do not exceed 250Vdc input signals.

6.1. Open SG10. For applications in which input voltages exceed

±100Vdc, also cut the 2 adjoining traces.

6.2. Configure the DMS-EB for span adjust using the procedure revi-

ously outlined for the DMS-30-1 version.

6.3. Calculate values for R1 and R2 as follows:

A typical value for R1 is 1MΩ. The sum of R1 + R2 should be

between 50kΩ and 10MΩ.

Where:

FSI = The attenuated voltage, between the meter's (–) IN LO and

(+) IN HI pins, needed to achieve the desired display readings

U1

SG1

xx.xx

x.xxx

SG2

Metal tab

points down

xxx.x

SG3

Figure 2. Installing U1

R1

To measure input voltages

greater than ±100Vdc,

open SG10 and also cut

these two etch paths.

SG10

Figure 3. Installing R1

APPLICATIONS

DMS-EB

Multi-Purpose Application Board for DMS-30 & DMS-40 Series Meters

www.murata-ps.com

MPM_DMS-EB.B01 Page 3 of 4