Greyline Portaflow PT400, Руководство пользователя

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3. Connect a calibrated ammeter to the 4-20mA
output and adjust the UP/DOWN Scroll keys
(Coarse) and LEFT/RIGHT Scroll keys 5 & 6 (fine)
until the output is exactly 4.0mA.
The DAC should indicate approximately 8000.
4. Press ENTER when done.
CALIBRATE 4mA DD-MM-YY HH:MM:SS
Dim: mm
Adjust the output current to 4mA
Use

to set, 5/6 to trim
DAC Value: 8000
Press

when done
5. With the meter still connected to the 4-20mA
output adjust the Scroll keys to obtain an output of
exactly 20mA.
The DAC should indicate approximately 40000.
6. Press ENTER when done.
CALIBRATE 20mA

DD-MM-YY HH:MM:SS
Dim: mm
Adjust the output current to 20mA
Use

to set, 5/6 to trim
DAC Value: 40000
Press

when done
4-20mA Signal scaling
Note: The 4-20mA 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.
7. With the instrument operating in the FLOW
READING mode, press the 4-20mA function key.
This will access the 4-20mA OUTPUT screen.
8. Select Flow at max. output and enter a value of
the flow rate that you want to associate with a
20mA output.
9. Select Flow at min. output and enter a value of
the flow rate that you want to associate with a 4mA
output.
This could be ‘0’.
4-20 mA OUTPUT DD-MM-YY HH:MM:SS
4-20 mA O/P is ON Dim: mm
mA Output Reading : 0.00
Output Range : 4-20
Units : l/min
Flow at max. output : 0.00
Flow at min. output : 0.00
Output mA for error : 22.00
Exit
10. Select Output mA for error and enter a value (max of about 23mA) that you want the 4-20mA output
to produce in the event of an error (e.g. if the flow-rate is outside the set range).
11. Upon completion press ENTER to return to the FLOW READING screen.
3.7.5 How to convert the measured current to flow rate
Assume the maximum flow rate is F
max
(l/min) and the minimum flow rate F
min
is ‘0’ (l/min), as shown.