DMS-EB2-C - MURATA MANUFACTURING - Datasheet.Directory

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DMS-EB2

Multi-Purpose Application Board

for DMS-20PC/LCD Meters

MPM_DMS-EB2.F02 Page 1 of 4

The DMS-EB2 Application Board was designed for quick and easy application/evalu-

ation of Murata Power Solutions’ subminiature DMS-20PC/LCD Series, 3½ Digit, LED/LCD

Display, Digital Panel Voltmeters. The DMS-EB2's versatility, low cost and direct DMS-

20PC/LCD plug-in compatibility makes interfacing a breeze. The DMS-EB2 covers many

common panel-meter applications while providing easy signal and power I/O terminations

(via a standard MOLEX connector) and plug-in versatility when changing from one applica-

tion to another.

The DMS-EB2 has provisions for such common applications as input dividers for

high input voltages, gain (span) adjustment, 9/12Vdc battery operation, and decimal

point placement. The board permits direct signal I/O wiring via the interface connector or

soldering directly to the board. The DMS-EB2 is fully compatible with all four versions of

the DMS-20PC/LCD (±200mV, ±2V, ±20V,

±200V) making it interchangeable from

meter to meter and application to application.

Solder gaps are conveniently placed on the

board and may be quickly bridged or cut as

required.

This low-cost addition to Murata Power

Solutions’ expanding line of subminiature

meters demonstrates our continuing commit-

ment to offer the most versatile, easy-to-use

panel-meter products.

FEATURES

 Gain (span) adjustment

 Input divider network for attenuating voltages

up to 250Vdc

 Operate meter and board from +5V supply or

9/12V battery

 On-board solder gaps for decimal point placement

 On-board I/O connector for easy power and signal input

Figure 1. DMS-EB2 Schematic Diagram





R5 U1

SG15

SG14 SG6 SG5

SG4

SG3

SG1

SG2

C1 +C2

SG10

123456

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DMS-EB2

Multi-Purpose Application Board

for DMS-20PC/LCD Meters

MPM_DMS-EB2.F02 Page 2 of 4

TECHNICAL NOTES

APPLICATIONS

1. LCD Backlighting: To backlight a DMS-20LCD meter, connect J1,

pin 3 (TEST/HOLD IN) to J1, pin 6 (GND). This allows for external

control, via a switch, of the backlight feature. The switch should

be rated for low voltage operation at 35mA.

2. 9V LCD Meters: DMS-20LCD-X-9 meters cannot be used in a

single-ended conguration, i.e., with (–) IN LO tied to GND. On

these models, both (–) IN LO and (+) IN HI have to be a minimum

of 1.5V above and 1.5V below J1 pins 6 and 5, respectively. To

operate from a 9V or 12V battery with (–) IN LO tied to GND, use

a 5V-powered meter (DMS-20LCD-X-5), install U1 (LM7805CT)

and open SG4.

3. Input Resistor Dividers: Always use 1%, or better, metal-lm

resistors for R1 and R2, and also make sure their power and volt-

age ratings are adequate for the given application.

4. Using U1 (LM7805CT): The input power range specied in the

Battery Operation section is rated conservatively assuming a

100mA LED meter or a 35mA backlit LCD meter. If a non-backlit

LCD model or the low-power LED model is used, the input volt-

As shipped, the DMS-EB2 is congured for single-ended operation.

This conguration is preferred for simple voltage measurements and will

generally cover most standard applications. Figure 1 indicates which

solder gaps are shipped closed from the factory.

Simply solder the board onto the meter (pin 1 to pin 1), connect

the power supply to J1, pin 5 (+V) and the power return to J1, pin 6

(GROUND).

1. Decimal Point Placement: Murata Power Solutions ships the

DMS-EB2 with all decimal point solder gaps (SG1, SG2 and

SG3) open. To enable a specic decimal point, close its respec-

tive solder gap with solder. When re-assigning decimal places

for subsequent applications, remember to unsolder previously

closed solder gaps.

Close SG1 for 1.999 (DP1)

Close SG2 for 19.99 (DP2)

Close SG3 for 199.9 (DP3)

2. Display Test (Not Available on LCD Models): Tie pin 4 (TEST/

HOLD OUT) to pin 3 (TEST/HOLD IN) to test the display of the

DMS-20PC. Do not leave the meter in the test mode for more

than 10 seconds. On LED meters with the HOLD option, tying

pins 3 and 4 together freezes the display reading.

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

its metal tab facing to the left as shown in Figure 3. Allowable

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

DMS-20PC-X-XS +7.5 to +12.6Vdc

DMS-20PC-X-XL +7.5 to +32Vdc

C2 (10µF/35V) can be added to reduce noise. Observe correct

polarity. Refer to Technical Note 4 for more information.

Figure 2. J1 Connector Pinout

Pin Function

1 (+) INPUT HI

2 (–) INPUT LO

3 TEST/HOLD IN

4 TEST/HOLD OUT

5 +V (Positive power connection)

6 –V (Ground, negative power return)

1 2 3 4 5 6

DMS-EB2-C Application board with mating connector and terminals

DMS-BZL3-C DMS-20 bezel assembly

DMS-BZL4-C DMS-20 bezel assembly with sealing gasket

4320-01074-0 6-position pc-board socket

Input Supply Range

See applicable meter's data sheet

Input Supply Range U1 (LM7805CT) Installed:

DMS-20PC-X-XS +7.5 to +12.6V

DMS-20PC-X-XL +7.5 to +32.0V

DMS-20LCD-X-5 +7.5 to +32.0V

DMS-20LCD-X-5B +7.5 to +12.6V

Operating and Storage Temperature

See applicable meter's data sheet

Humidity 0 to 95%, non-condensing

Dimensions 1.25" (31.8mm)L x 0.75" (19.1mm)H

J1 Connector & Wire Information

Terminal Type MPS P/N 39-2099090

Crimp Tool MPS P/N 39-2099000

Wire Size 22 to 26 AWG

Insulation Diameter 0.062" (1.57mm) max.

Stripping Length 0.100" to 0.125"

(2.54 to 3.17mm)

Ordering Information

Functional Specications (TA = 25°C) age range can be extended up to 32Vdc.

A 10µF/35V tantalum capacitor (C2 on schematic) should be installed

with the polarized end next to the + symbol on the DMS-EB2. This is

especially important if the power source is located far from U1.

5. Soldering: Murata Power Solutions recommends the use of "no- clean"

See www.murata-ps.com/dpm-availability for model-speciﬁc

availability.

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DMS-EB2

Multi-Purpose Application Board

for DMS-20PC/LCD Meters

MPM_DMS-EB2.F02 Page 3 of 4

Figure 3. Installing U1

Figure 4. Installing R1

SG10

To measure input voltages

greater than ±100Vdc,

these two etch paths.

open SG10 and also cut

SG1

SG2 SG3

TO-3-style tab

points to left

4. Calibration Adjustment: The DMS-EB2 has provisions for adjusting the

calibration of the DMS-20 meter. Calibration adjustment is useful when

an input divider (using R1 and R2) is necessary to scale the input voltage.

The calibration potentiometer allows "tweaking" of the display reading.

Using the calibration potentiometer

Adjust the calibration pot on the back of the meter as desired. The

adjustment range is only 3/4 of a turn. Do not force the pot past its end

stops.

5. Dierential 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.

6. Measuring Input Voltages Greater than 1.999Vdc (Use DMS-20PC/

LCD-1 Only):

CAUTION: Do not exceed 250Vdc input signal.

1. Open SG10. For applications in which input voltages exceed ±100Vdc,

also cut the 2 adjoining traces.

2. Calculate values for R1 and R2 as follows:

R2 = (FSI x R1) / ( |VIN| - FSI)

Where:

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 (beween pins 1 and 2)

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

between 50kΩ and 10MΩ.

3. Enable DP3 by soldering SG3.

4. Calibrate the meter using a known voltage source. Adjust the internal

gain potentiometer to compensate for variations in R1 and R2.

Example

VIN is 199.9Vdc, and the display reading must be "199.9".

1. Assume R1 = 1.0MΩ.

2. R2 = (FSI x R1) / ( |VIN| - FSI)

R2 = (1.999 x 1,000,000) / (199.9 - 1.999)

R2 = 10101.01Ω or 10kΩ

7. Current Measurements (Use 200mV Model, DMS-20PC/LCD-0): The

following instructions are for measuring current derived from the DMS-

20PC/LCD's power source. When measuring current that is oating with

respect to J1, pin 6 (GROUND), leave SG5 closed.

CAUTION: Do not exceed 1 Ampere input current.

1. Install R2 (R2 = FSR / (IMAX x 10000)) where FSR is the

desired reading (0 -1999) and IMAX is between 0 -1 Ampere.

2. Open SG5.

3. Apply input signal (current) to (+)IN HI and (–) IN LO.

4. Adjust internal gain pot for desired full scale readings.

5. Enable decimal points using either SG1, SG2 or SG3.

Example

A 1.0 Ampere input must read "1.000" on the display.

R2 = 1000 / (1 x 10000)

R2 = 0.1 Ohm

Enable DP1 via SG1 for reading of 1.000

8. Displaying DMS-20PC/LCD's Power Source

(Use DMS-20PC/LCD-2, 5V-Powered Models Only):

1. If the power source is higher than 5Vdc, be sure to install U1 and cut

SG4. See Battery Operation section and Technical Note 4.

2. Solder a short piece of jumper wire across the two holes labeled J2.

3. Close SG2 to enable DP2.

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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

Murata Power Solutions, Inc.

ISO 9001 and 14001 REGISTERED

This product is subject to the following operating requirements

and the Life and Safety Critical Application Sales Policy:

Refer to: http://www.murata-ps.com/requirements/

DMS-EB2

Multi-Purpose Application Board

for DMS-20PC/LCD Meters

MPM_DMS-EB2.F02 Page 4 of 4