DMS-EB-C - Farnell

Multi-Purpose Application Board for DMS-30 & DMS-40 Series Meters
Accommodates 3½ and 4½ digit meters
Gain (span) and offset (zero) adjustments for
DMS-30 meters
Input divider network for high voltages
The DMS-EB Application Board covers many common panel meter applications while providing
simple signal and power I/O terminations (via a standard MOLEX connector) for DATEL's DMS-30 and
DMS-40 Series, LED/LCD Display, Digital Panel Voltmeters. The unique plug-and-play design of the
DMS-EB makes changing from application to application and meter to meter quick, easy and inexpensive.
The highly versatile DMS-EB has provisions for such common applications as attenuation of high
input voltages, gain (span) and offset (zero) adjustments, 9/12V battery operation, and direct decimal
point placement. The DMS-EB is compatible with all four versions of the DMS-30 and DMS-40 Series
(±200mV, ±2V, ±20V and ±200V) making it interchangeable from meter to meter and application to
application. Solder gaps conveniently placed on the board are easily bridged or cut configuring the board
to meet each application's specific requirements.
This low-cost addition to DATEL's expanding line of miniature meters is evidence of our continuing
commitment to offer the most versatile, easy-to-use, panel meter products.
Operate meter and board from +5V supply or
9/12V battery
Solder gaps for decimal placement
Same size as DMS-30/40 Series meters
2.02" (51.31mm)L x 0.83" (21.08mm)W
c Components are user-supplied and not part
of the standard product.
d For DMS-40 meters only.
Figure 1. DMS-EB Schematic Diagram for DMS-30 Meters
For full details go to
MPM_DMS-EB.B02 Page 1 of 4
Multi-Purpose Application Board for DMS-30 & DMS-40 Series Meters
Ordering Information
Application board with mating connector
and terminals
DMS-BZL1-C DMS-30/40 bezel assembly
DMS-BZL2-C DMS-30/40 bezel assembly with
sealing gasket
Functional Specifications
(TA = +25°C)
Input Supply Range
See applicable meter's data sheet
Input Supply Range
U1 (LM7805CT) Installed:
+7.5 to +12.6V
+7.5 to +18.0V
+7.5 to +32.0V
+7.5 to +12.6V
Operating and Storage Temperature
See applicable meter's data sheet
0 to 95%, non-condensing
2.02" (51.31mm)L x 0.83" (21.08mm)W
J1 Connector & Wire Information
Terminal Type
Crimp Tool
Wire Size
Insulation Diameter
Stripping Length
DATEL P/N 4400-01032-0
DATEL P/N 39-2099000
22 to 26 AWG
0.062" (1.57mm) max.
0.100" to 0.125" (2.54 to 3.17mm)
As shipped, the DMS-EB is configured for 5V-powered DMS-30 3½
digit meters operating in the single-ended mode (SG5 closed) using the
meter's internal reference (SG13 closed). This configuration is the most
common and works well for most simple voltage measurements.
Many of the applications described below apply to both DMS-30
and DMS-40 meters. However, Application 5, installing the span (R4) and
offset (R5) adjust potentiometers, can only be used with DMS-30 meters.
Also note that some of the other applications require the installation of
R4 and R5. See Technical Note 5 when using the DMS-EB with DMS-40
Please read all of the following technical notes and perform any
required modifications before soldering the DMS-EB onto the meter
(aligning pin 1 to pin 1). After soldering, carefully connect +5Vdc to +V
(J1, pin 5) and power return to –V (J1, pin 6).
1. LCD Backlighting: For DMS-30LCD backlit models, close SG15. For
DMS-40LCD backlit models close SG18. See the DMS-30LCD or the
DMS-40LCD data sheets for limitations on backlighting 9V-powered
2. 9V-Powered, LCD Display Models: DMS-30LCD-X-9 and DMS40LCD-X/X-9 meters cannot be used in single-ended input configurations, i.e., LO (J1, pin 2) cannot be connected to GND (J1, pin 6). When
operating from a 7.5 to 14Vdc power source with a single-ended
input, use a +5V-powered meter and install U1 (see Battery Operation
section and Technical Note 4).
Close SG6 when measuring floating inputs with a 9V-powered meter
(floating inputs are described in Technical Note 7). SG6 provides a bias
reference for the input signal by tying LO to the meter's Analog Common terminal (pin 10).
3. Input Resistor Dividers: Use 1%, or better, metal film resistors for
R1 and R2 in DMS-30 applications, and 0.5%, or better, in DMS-40
applications. Using tight-tolerance resistors in input divider networks
allows most final calibration adjustments to be made with the meter's
rear calibration pots through the access holes provided. Make sure
the resistor power and voltage ratings are adequate for the given
4. Using U1 (LM7805CT): The power supply voltage range listed in the
Battery Operation section is rated for a 150mA LED meter or a 35mA
backlit LCD meter. A 10μF/35V tantalum capacitor (C2) should be
installed with the polarized end next to the + symbol on the DMS-EB.
This is especially important if the power supply is located far from U1.
5. DMS-40 Meters: When the DMS-EB is used with DMS-40PC or DMS40LCD meters, be sure to open SG13. The RN-DMS resistor accessory kit comprised of resistor R3 and potentiometers R4 (Gain/Span)
and R5 (Offset/Zero), cannot be used with DMS-40 series meters. To
change the input range on DMS-40LCD meters from the low range to
the high range, close SG16.
6. Calibration Potentiometer Adjustment Holes: Two overlapping
holes on the DMS-EB provide access to the ¾-turn calibration potentiometer on DMS-30 meters and the 3-turn potentiometer on DMS-40
meters. The adjustment range of both pots is very narrow. See the
applicable product data sheet for more information on each meter’s
calibration potentiometers.
7. Input Configurations: The DMS-EB is supplied with SG5 closed. SG5
connects J1, pin 2 (LO) to power return J1, pin 6 (GND) and configures
the meter for single-ended operation, that is, the low side of the input
is at system ground or zero Volts. SG5 must also be closed when
measuring floating inputs. Floating inputs are signals which have no
electrical connection, or reference to, the power supply which powers
the meter.
In applications in which input LO is connected to ground elsewhere in
the system, and SG5 is closed, unwanted ground-loop induced display
errors may develop. Ground loops, a condition in which display drive
currents also flow through the input signal wiring, can cause unstable
display readings. If this occurs, try opening SG5 to see if the display
SG5 must be open when measuring differential inputs that are referenced to the same supply which powers the meter. DMS Application
Note 2 (Input Configurations, Power Supplies and Ground Loops)
provides a detailed discussion of input configurations.
8. Soldering: DATEL recommends the use of "no-clean" solders when
installing or making modifications to the DMS-EB.
MPM_DMS-EB.B02 Page 2 of 4
Multi-Purpose Application Board for DMS-30 & DMS-40 Series Meters
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 reassigning decimal places for subsequent applications, remember to
open previously closed solder gaps.
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 potentiometer 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.
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:
Using Full Range Span Adjustment (DMS-30 Only)
+7.5 to +12.6V
+7.5 to +18.0V
+7.5 to +32.0V
+7.5 to +12.6V
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 reviously outlined for the DMS-30-1 version.
6.3. Calculate values for R1 and R2 as follows:
Metal tab
points down
To measure input voltages
greater than ±100Vdc,
open SG10 and also cut
these two etch paths.
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 follows: 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 components and solders when making modifications to DMS-EB.
Figure 3. Installing R1
A typical value for R1 is 1MΩ. The sum of R1 + R2 should be
between 50kΩ and 10MΩ.
R2 = (FSI x R1) / ( |VIN| - FSI)
FSI = The attenuated voltage, between the meter's (–) IN LO and
(+) IN HI pins, needed to achieve the desired display readings
VIN = Input voltage at J1 (between pins 1 and 2)
Once installed, these components permit the span and zero adjustments described in the following sections. R3 and R4 provide span
adjust, while R5 applies and offset voltage to (-) IN LO (J1, pin 2).
MPM_DMS-EB.B02 Page 3 of 4
Multi-Purpose Application Board for DMS-30 & DMS-40 Series Meters
7.1. Install R2: R2 = FSR / (IMAX. x 10000) where FSR is the desired
meter reading (0 -1999) and IMAX is between 0 -1 Ampere.
VIN is 0-5Vdc, and the display reading must be "000" to "1500."
7.2. Open SG5.
1. Assume R1 = 1.0MΩ.
7.3. Configure the DMS-EB for span adjust using the procedure previously outlined for the DMS-30-0 version.
2. R2 = (FSI x R1) / ( |VIN| - FSI)
R2 = (1.500 x 1,000,000) / (5.0 - 1.500)
R2 = 428,571Ω or 432kΩ
7.4. Apply input signal (current) to (+) IN HI and (–) IN LO.
7.5. Adjust R4 for desired full scale readings.
3. Calibrate the meter using a known voltage source. Adjust R4 to
compensate for variations in R1 and R2.
7. Current Measurements (Use 200mV Model, DMS-30-0): The following instructions are for measuring current derived from the DMS30/40's power source. When measuring current that is floating with
respect to J1, pin 6 (POWER RETURN), leave SG5 closed.
7.6. Enable the appropriate decimal point using either SG1, SG2, SG3
or SG-17.
A 0.100 Ampere input must read "100.0" on the display.
CAUTION: Do not exceed 1 Ampere input current
R2 = 1000 / (0.1 x 10000)
R2 = 1 Ohm
Enable DP3 via SG3 for a reading of "100.0."
(+) (–) IN OUT
Figure 4. DMS-EB Board
Murata Power Solutions, Inc.
11 Cabot Boulevard, Mansfield, MA 02048-1151 U.S.A.
ISO 9001 and 14001 REGISTERED
Murata Power Solutions, Inc. makes no representation that the use of its products in the circuits described herein, or the use of other
technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not imply
the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Specifications are subject to change without
© 2012 Murata Power Solutions, Inc.
MPM_DMS-EB.B02 Page 4 of 4