DATEL, Inc. 11 Cabot Boulevard, Mansfield, MA 02048-1151

Tel: (508) 339-3000

(800) 233-2765

Fax: (508) 339-6356

Internet: www.datel.com

E-mail: sales@datel.com

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DATEL 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 notice. The DATEL logo is a registered DATEL, Inc. trademark.

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Examples

As shipped, the DMS-EB-LP is factory calibrated to read "000" for a

4mA input and "1999" for a 20mA input but may require recalibra-

tion when connected to a DMS-30LCD-1-5 digital voltmeter.

The following worst-case procedure assumes the DMS-EB-LP is

completely mis-adjusted, i.e., both potentiometers and the DIP

switches are randomly set.

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

clockwise, roughly 22 turns, and place SW1-SW8 to OFF

(down position).

2. Set SW1 to ON (up position). See DIP switch setting #3 in

Table 1.

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 "1999". Repeat steps 3 and 4 to make sure the

adjustments do not affect one another.

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

SW7 to ON (DP1, DP2 or DP3 respectively).

NOTE: If a display reading other than "000" to "1999" is desired,

refer to Table 1 for SW1-SW4 settings.

1. Desired display readings are:

4mA ="0.00"

20mA = "2.00"

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

SW6. Apply 4mA and adjust R3 so the display reads "0.00".

Apply 20mA and adjust R7 so the display reads "2.00".

2. Desired display readings are:

4mA =" –100"

12mA = "000"

20mA = "100"

Use DIP-switch setting #4. Apply 12mA and adjust R3 so the

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

reads "100". Apply 4mA and the display should read "–100". For

these display readings, no decimal points are used. Set SW5,

SW6 and SW7 to OFF (down position).

3. Desired display readings are:

4mA = "-157.5"

12mA = "00.0"

20mA = "157.5"

Use DIP-switch setting #7 and enable decimal point DP3 via

SW7. Apply 12mA and adjust R3 so the display reads "000".

Apply 20mA and adjust R7 so the display reads "157.5".

Apply 4mA and the display should read "–157.5".

4. Desired display readings are:

4mA = ".000"

12mA = ".250"

This example is not as straightforward as the previous three.

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 the chart, we can

now select DIP-switch setting #2 and enable DP1 via SW5. Apply

4mA and adjust R3 so the display reads ".000". Apply 12mA and

adjust R7 so the display reads ".250".

Operating and Setup Instructions

Table 1. DIP-Switch Settings

NOTE: When looking up DIP-switch settings in the Table and the

desired display readings happen to fall between two switch

settings, try performing the adjustments with both settings to

determine which one offers the better settability. Please keep in

mind that the DMS-30LCD meter has an accuracy specification

of ±2 counts (max.). Thus, it may not always be possible to

obtain the exact desired display reading.

Display Reading

SW1

SW2

SW3

SW4

1. 000 to 100-300

On

On

On

Off

2. 000 to 400-600

Off

On

Off

Off

3. 000 to 700-1999

On

Off

Off

Off

4. ±100

On

On

On

Off

5. ±200 to ±300

On

On

Off

Off

6. ±400 to ±600

On

Off

Off

Off

7. ±700 to ±1900

Off

Off

Off

On

DMS-EB-LP

4-20mA

CURRENT

LOOP

APPLICA TION

BO ARD

DS-0304A 1/98