Performance/Functional Specifications

The DMS-20LCD-4/20, using any of the DIP-switch settings described above,

can withstand overcurrents, including those resulting from accidental reverse-

polarity connections, up to ±40mA without sustaining any damage.

Because DATEL's DMS-4/20 loop-powered meters employ active circuitry to

convert the loop current into a voltage, the meters' effective series impedance

varies in a manner that maintains the loop voltage drop constant over the full

4-to-20mA current range. Listed impedance specification applies at 20mA.

DMS-20LCD-4/20S-C

Unipolar reading, loop-powered LCD meter

DMS-20LCD-4/20B-C

Bipolar reading, loop-powered LCD meter

DMS-20LCD-4/20P-C

Positive reading, loop-powered LCD meter

DMS-BZL3-C

Bezel assembly

DMS-BZL4-C

Bezel assembly with sealing gasket

DMS-20-CP

Panel cutout punch

A panel-mount retaining clip is supplied with each model.

1. Desired display readings are:

4mA ="0.00"

20mA = "6.00"

Use DIP-switch setting #3 in Table 1 and enable decimal point DP2 via

SW5. Apply 4mA and adjust R3 so the display reads "0.00". Apply

20mA and adjust R7 so the display reads "6.00".

2. Desired display readings are:

4mA = "000"

20mA = "800"

Use DIP-switch setting #2 in Table 1. Apply 4mA and adjust R3 so the

display reads "000". Apply 20mA and adjust R7 so the display reads

"800". For these display readings, no decimal points are used. Set

SW4, SW5 and SW6 to OFF.

3. Desired display readings are:

4mA = ".000"

12mA = ".250"

This example is not as straightforward as the previous two. Notice that

12mA is exactly halfway between 4mA and 20mA. If we assume that

the input could go up to 20mA, the display reading would then be: 2

x .250 or ".500". From Table 1 we can now select DIP-switch setting

#4 and enable DP1 via SW4. Apply 4mA and adjust R3 so the display

reads ".000". Apply 12mA and adjust R7 so the display

reads ".250".

Examples (DMS-20LCD-4/20S-Unipolar Model)

DMS-20LCD-4/20S (Unipolar Reading Model)

As shipped, the DMS-20LCD-4/20S is factory calibrated to read "000"

for a 4mA input and "1000" for a 20mA input. The following worst-case

procedure assumes the DMS-20LCD-4/20S is completely mis-adjusted,

i.e., both potentiometers and the DIP switches are randomly set. When

Current Loop Inputs

Min.

Typ.

Max.

Units

Full Scale Input Range

+3.8

–

+20.4

mA

Input Impedence

–

80

100

Voltage Drop

–

1.8

2.0

Volts

Overvoltage Protection

–

–

±40

mA

Performance

Sampling Rate

2.5 reading per second

Accuracy (1 minute warm-up):

±0.05%FS ±1 Count

Temperature Drift (0 = +60°C)

–

±0.15

±0.3

Cnts/°C

Display

Display Type and Size

3½ digit, 0.37"/9.4mm high LCD

Polarity Indication

"–" for negative readings

Overrange Indication

"–1_ _ _ " for negative inputs

"1_ _ _ " for positive inputs

Physical/Environmental

Operating Temperature

0

–

+60

°C

Storage Temperature

–20

–

+75

°C

Humidity (non-condensing)

0–

95

%

Case Material

Polycarbonate

Weight

0.6 ounces (17 grams)

Ordering Information

1

2

3

4

56

ON

123

4

5

6

ON

12

3

4

56

ON

performing DIP-switch settings, be sure the DIP switch's small actuators

are firmly engaged in their fully-ON or fully-OFF positions.

1. Set R7 (full scale span/gain adjust) and R3 (zero/offset adjust) fully

clockwise, roughly 22 turns, and place SW1-SW6 to OFF.

2. Select DIP switch setting #2.

1. Set R7 (full scale span/gain adjust) and R3 (zero/offset adjust) fully

clockwise, roughly 22 turns, and place SW1-SW6 to OFF.

2. Select DIP switch setting #2.

3. Apply a precision 4mA input, with proper polarity, and adjust R3 until

the meter's display reads "000".

4. Apply a precision 20mA input and adjust R7 until the meter's display

reads "1000". Repeat steps 3 and 4 to make sure the adjustments do

not affect one another.

5. Select the appropriate decimal point by setting SW4, SW5 or SW6 to

ON (DP1, DP2 or DP3 respectively).

NOTE: If a display reading other than "000" to "1000" is desired,

refer to DIP–Switch Settings Table 1 for SW1–SW3 settings.

DMS-20LCD-4/20 Series

4-20mA Input Loop-Powered Ultra-Low 1.8V Loop Drop

3½ Digit LCD Display Process Monitors

MPM_DMS20LCD-420.B02 Page 2 of 6

www.murata-ps.com

OPERATING AND SETUP INSTRUCTIONS