Decimal Point Placement; Display Test; Battery Operation; Differential Input Signals (Signal Referenced To Power Source) - Murata Ps Dms-Eb Quick Start Manual

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
DMS-30/40PC-X-XL
DMS-30/40LCD-X-5
DMS-30/40LCD-X-5B
U1
SG3
xxx.x
Figure 2. Installing U1

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).
Multi-Purpose Application Board for DMS-30 & DMS-40 Series Meters
+7.5 to +12.6V
+7.5 to +18.0V
+7.5 to +32.0V
+7.5 to +12.6V
Metal tab
points down
SG2
SG1
xx.xx
x.xxx
www.murata-ps.com

APPLICATIONS

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.
R2 = (FSI x R1) / ( |V
Where:
FSI = The attenuated voltage, between the meter's (–) IN LO and
(+) IN HI pins, needed to achieve the desired display readings
V = Input voltage at J1 (between pins 1 and 2)
IN
Technical enquiries email: sales@murata-ps.com, tel:
DMS-EB
R1
SG10
To measure input voltages
greater than ±100Vdc,
open SG10 and also cut
these two etch paths.
Figure 3. Installing R1
IN | - FSI)
MPM_DMS-EB.B01 Page 3 of 4
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