3: Operating Procedures
29
8. 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 4.00 mA.
The DAC should indicate approximately 8000.
9. Press
ENTER
when done.
10. With the meter still connected to the 4 to 20 mA
output adjust the Scroll keys to obtain an output
of exactly 20.00 mA.
The DAC should indicate approximately 40000.
11. Press
ENTER
when done.
4-20mA 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.
12. With the instrument operating in the
FLOW
READING
mode, press the
4-20mA
function
key. This will access the
4-20mA OUTPUT
screen.
13. Select
Flow at max. output
and press
ENTER, then
enter a value of the flow rate
that you want to associate with a 20.00 mA
output.
14. Select
Flow at min. output
and press
ENTER
then enter a value of the flow rate that
you want to associate with a 4.00 mA output.
This could be ‘0’.
15. Select
Output mA for error
and enter a value (max of about 26 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).
16. Upon completion press
ENTER
to return to the
FLOW READING
screen.
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
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
4-20 mA OUTPUT
DD-MM-YY HH:MM:SS
4-20 mA O/P is ON
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
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