Operating procedures – Dwyer Series PUF User Manual

Page 40

3: Operating Procedures

4 to 20 mA Signal scaling

Note: The 4 to 20 mA can be set to represent a particular flow range. It is also possible to enter a negative figure
for the minimum output and this would enable a reverse flow to be monitored.

10. Select

Output mA for error and enter a value (default is 22 mA) that you want the 4 to 20 mA output to

produce in the event of an error (e.g. if the flow-rate is outside the set range).

11. Upon completion press the

ENTER key to return to the FLOW READING screen.

Connect a calibrated ammeter to the 4 to 20 mA
output and adjust the

UP/DOWN Scroll keys

(Coarse) and

LEFT/RIGHT Scroll keys 5 & 6

(fine) until the output is exactly 4.0 mA.
The DAC should indicate approximately 8000.

Press the

ENTER key when done.

CALIBRATE 4mA

DD-MM-YY HH:MM:SS

Adjust the output current to 4mA

Use

to set, 5/6 to trim

DAC Value: 8000

Press

when done

With the meter still connected to the 4 to 20 mA
output adjust the Scroll keys to obtain an output
of exactly 20 mA.
The DAC should indicate approximately 40000.

Press the

ENTER key when done.

CALIBRATE 20mA

DD-MM-YY HH:MM:SS

Adjust the output current to 20mA

Use

to set, 5/6 to trim

DAC Value: 40000

Press

when done

With the instrument operating in the

FLOW

READING mode, press the 4-20mA function key.
This will access the

4-20mA OUTPUT screen.

Select

Flow at max. output and enter a

value of the flow rate that you want to associate
with a 20 mA output.

Select

Flow at min. output and enter a

value of the flow rate that you want to associate
with a 4 mA output. This could be ‘0’.

4-20 mA OUTPUT

DD-MM-YY HH:MM:SS

4-20 mA O/P is ON

Qxx.xx%

mA Output Reading : 0.00

Output Range : 4-20

Units : gal/min

Flow at max. output : 0.00

Flow at min. output : 0.00

Output mA for error : 22.00

Exit