Det-Tronics R8471NH34001,2,3 Single Channel Gas Controller, NH3 - Manual (Page 22)

95-8529 1.1 20
CURRENT OUTPUT CALIBRATION
The 4 to 20 milliampere output is calibrated at
the factory to provide a degree of accuracy that
is satisfactory for most applications. However,
the highest level of accuracy can be obtained by
performing the following procedure.
1. A dc current meter capable of measuring 4 to 20
milliamperes must be connected to the current loop
output. This can be accomplished by connecting a
dc ammeter in series with the load or by connecting
a digital dc voltmeter across a known load
resistance and calculating the current flow using the
formula:
I = voltage/load resistance.
2. Press and hold the Set button, then immediately
press the Reset button. (The Reset button must
be pressed within one second of pressing the
Set button.) Release both buttons. The Low LED
flashes slowly while the system generates a 4 ma
output.
3. Press the Reset (increase) or Set (decrease) button
to obtain a 4.0 ma reading on the meter. (Holding
the button will cause the output to change rapidly.)
4. When no adjustments have been made for 5
seconds, the controller automatically switches to a
20 ma output. This is indicated by a flashing High
LED. Press the appropriate button to obtain a 20.0
ma reading.
5. When no adjustments have been made for 5
seconds, the controller generates the current output
level for the calibrate mode. This is indicated by
a flashing CAL LED. Press the appropriate button
to obtain the desired current output level for the
calibrate mode. (The default level is 4.0 ma.)
6. When no changes have been made for 5 seconds,
the system automatically returns to the Normal
operating mode and saves the data in non-volatile
memory.
7. Remove the meter from the system output and
reconnect the outputs for normal operating
conditions.