Vaisala GMP231 - Manual (Page 48)

User's Guide _______________________________________________________________________
46 ___________________________________________________________________ M211501EN-C
Set Analog Output Clipping and Error
Limit
Use the AOVER command to define the behavior of the analog output
when the measured value is outside the scaled output range.
AOVER [channel clip% valid%]
where
channel = Analog output channel, only 1 can be selected.
clip%
= Output margin (%) at which the output is clipped.
valid% = Output margin (%) at which the output of the channel
goes into the error state. The error state is defined using
the AMODE command, see section Set Analog Output
Mode on page 45.
For example, first check the analog output settings using ASEL,
AMODE, and AOVER commands:
pass 1300
asel 1
Aout 1 quantity : CO2(0 ... 50000)
amode 1
Aout 1 range (mA) :0.00 ... 20.00 (error : 23)
aover 1
Aout 1 clipping :10.00 %
Aout 1 error limit :10.00 %
Now give the following AOVER command:
aover 1 5 10
Aout 1 clipping : 5.00 %
Aout 1 error limit :10.00 %
The analog output now behaves like this:
- Clipping is now set to 5%, meaning the output is allowed to vary
between 0 ... 21 mA. The analog channel will output the measurement
for 0 ... 52500 ppm, but range 0 ... 20 mA remains scaled to
0 ... 50000 ppm.
- Error limit is 10%, which means the output will show the error state
(23 mA) when the measured value is 10% outside the scaled output
range. With the settings above, this will happen if the measured CO
2
concentration is outside range 0 ... 55000 ppm.
- The output will never actually be between 21 mA and 23 mA because
of clipping.