Adjusting the 4-20 mA Outputs
Chapter 4
: 4-20 mA Signal Configuration / Operation
Airnet® II 4-Channel Particle Sensors Operations Manual
4-5
Adjusting the 4-20 mA Outputs
The 4-20 mA outputs can be adjusted to compensate for normal variations in the
electrical components. The 4-20 mA outputs are only guaranteed to be /- 0.2
mA (1% full scale) without any adjustment.
Each of the five 4-20 mA outputs can be adjusted separately. A current meter must be
connected to the 4-20 mA output to be adjusted.
To adjust a 4-20 mA output, connect to the setup interface of the sensor:
1.
Issue the command
current adjust
.
2.
The operator will be prompted for the index of the 4-20 mA output to be
adjusted (Output Channels 1-5 are indexed 0-4). The offset and scale factors for
the selected output will be set to 0 and 1 respectively.
3.
The sensor will now apply 4 mA to the selected output. The operator will be
prompted to enter the actual reading as measured by the current meter. This
will calculate the appropriate offset factor to be applied to that output.
4.
The sensor will now apply 20 mA to the selected output. The operator will be
prompted to enter the actual reading as measured by the current meter. This
will calculate the appropriate scale factor to be applied to that output.
5.
The operator will be prompted to enter "
y
" to accept the channel adjustment.
If accepted, the new offset and scale factors will be saved. Whether accepted or
not, the unit will reboot and restart normal operation.
