DMS-20PC-4/20P Ver la hoja de datos (PDF) - DATEL Data Acquisition products

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DMS-20PC-4/20P

Subminiature 4-20mA Loop-Powered 3½ Digit, LED ProcessMonitors

DATEL Data Acquisition products  

DMS-20PC-4/20

3½ D I G I T, L E D D I S P L AY, 4 - 2 0 m A L O O P - P OW E R E D M E T E R S

1. Set R3 fully counterclockwise (minimum offset position) and R7 fully

clockwise (minimum differential span position), roughly 22 turns.

2. Subtract 040 from 200 to yield a differential value of 160; use this value

to select DIP-switch setting #5 in Table 3. Enable decimal point DP3 by

placing SW6 to the ON position.

3. Set the transmitter’s output to 4.0mA and carefully adjust R3 clockwise

until the meter’s display reads “000”.

4. Set the transmitter’s output to 20.0mA and adjust R7 counterclock-

wise until the meter’s display reads “16.0”.

5. Set the transmitter back to 4.0mA and slowly adjust R3 clockwise until

the display reads “04.0”. Reapply 20.0mA and the display should now

read “20.0”. Repeat steps 3, 4 and 5 to make sure the adjustments did

not affect one another.

Table 3. DMS-20PC-4/20P (Positive Reading Model)

DIP-Switch Settings

Display Reading

SW1 SW2 SW3

Differential Range 4mA Input 20mA Input

1. 800-1400

900

2. 500-800

850

3. 350-500

800

4. 250-350

750

5. 150-250

750

1700

Off Off Off

1350

On Off Off

1150

Off On Off

1000

Off Off On

900

On On On

Table 4. Decimal Point Settings

SW4

SW5

SW6

DP1

DP2

DP3

Examples (DMS-20PC-4/20P-Positive Model)

1. Desired display readings are:

ON

4mA = “650”

20mA = “950”

1 2 34 56

Use DIP-switch setting #4 in Table 3 since subtracting 650 from 950

yields a differential value of 300. Apply 4mA and adjust R3 until the

display reads “000”. Apply 20mA and adjust R7 until the display reads

“300” (the differential value previously calculated). Apply 4mA and

adjust R3 until the display reads “650”. Apply 20mA and verify that the

display reads “950”.

2. Desired display readings are:

ON

4mA = “4.00”

20mA = “19.99”

1 2 34 56

This example illustrates the DMS-20PC-4/20P’s capability to display

higher differential readings than those indicated in Table 3. This exam-

ple also illustrates how the DMS-20PC-4/20P can be used to display

the output levels of a 4-20mA loop transmitter with higher precision

(0.01mA versus 0.1mA) than described above.

Subtracting 400 from 1999 yields a differential of 1599, a value not

listed in Table 3. However, use DIP-switch setting #1 in Table 3 since

this setting has the highest overall offset/span adjustment capabilities.

Enable DP2 via SW5 then apply 4mA and adjust R3 so the display

reads “0.00”. Apply 20mA and adjust R7 so the display reads “15.99”.

Apply 4mA and adjust R3 until the display reads “4.00”. Apply 20mA

and check to see that the display reads “19.99” or just overranges

(“1—“). Repeat adjustment procedure if necessary.

➀

PROGRAMMABLE

LOGIC CONTROLLER

TRANSDUCER

INPUT

TRANSMITTER &

SIGNAL CONDITIONER

+

+

4-20mA

–

+ (TB1-1)

–

4-20mA

– (TB1-2)

DMS-20PC-4/20

GAIN

R7

+

A/D

Vsig

R3

–

ZERO

+24Vdc

SUPPLY

+ +24V

–

➀ Shown for illustrative purposes only, may not be present in all applications

Figure 2. Typical DMS-20PC-4/20 Connection Diagram

DATEL, Inc., Mansfield, MA 02048 (USA) • Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 • E–mail: sales@datel.com • Internet: www.datel.com

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