DMS-20PC-4/20 Series

Subminiature 4-20mA Loop-Powered

3½ Digit LED Process Monitors

MPM_DMS20pc-420.C02 Page 2 of 6

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OPERATING AND SETUP INSTRUCTIONS

Performance/Functional Specifications

The DMS-20PC-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.

When looking up DIP-switch settings in the Tables and the desired display

readings can be achieved with either of two different settings, using the higher

setting # will produce less sensitive offset (R3) and span (R7) adjustments.

Please keep in mind that the DMS-20PC standard meter (from which the DMS-

20PC-4/20 is derived) has an accuracy specification of ±2 counts (max.). Thus,

it may not always be possible to obtain the exact desired display reading.

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.

Display Reading

SW1

SW2

SW3

4mA

20mA

1. 000 to 1050-1999

Off

Off

Off

2. 000 to 650-1350

On

Off

Off

3. 000 to 450-800

Off

On

Off

4. 000 to 300-500

Off

Off

On

5. 000 to 200-300

On

On

On

Table 1. DMS-20PC-4/20S (Unipolar Model) DIP-Switch Settings

DMS-20PC-4/20S-C

Unipolar reading, loop-powered LED meter

DMS-20PC-4/20B-C

Bipolar reading, loop-powered LED meter

DMS-20PC-4/20P-C

Positive reading, loop-powered LED meter

DMS-PS4-CM-C

+24V/0.45A AC/DC power supply module

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.

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

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

As shipped, the DMS-20PC-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-20PC-4/20S is completely mis-adjusted,

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

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

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

Current Loop Input

Min.

Typ.

Max.

Units

Full Scale Input Range:

+4

–

+20

mA

Input Impedence:

–

250

Voltage Drop

–

4.5

5.0

Volts

Overvoltage Protection

––

±2

mA

Performance

Sampling Rate

2.5 reading per second

Accuracy (1 minute warm-up):

±0.05%FS ±1 Count

Temperature Drift (0 = +50°C)

–

±0.15

±0.3

Cnts/°C

Display

Display Type and Size

3½ digit, 0.37"/9.4mm high red LED

Polarity Indication

"–" for negative reading

Overrange Indication

"–1____" for negative Vin

"1____" for positive Vin

Physical/Environmental

Operating Temperature

0

–

+60

°C

Storage Temperature

–40

–

+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