Pacific Research Solutions PET-820 User Manual
Page 51
Pacific Research
PET-820 User Manual
Page 50
6.7
CALIBRATION, ANALOG INPUT OPTION
Calibration adjustments to the analog input option are done via the two potentiometers located on the analog board (reference
Figure 6.2 for information on the location of these two adjustments). In order to make these adjustments, you will need a
precision voltage source or an adjustable voltage source and a volt meter with a minimum of 4 1/2 digits of resolution.
First we will check and adjust the low range, then repeat the same procedure for the high range using a higher voltage.
1.
Disconnect all analog signals that are connected to the analog board and connect your voltage source, channel 1 of
the analog board. Turn power to the PET-820 on and make sure the unit is not armed.
2.
Set the precision voltage source to +0.4000 volts. Other lower voltages may be used, but try to use the highest voltage
to +0.4000 volts as possible. If you don't have a precision voltage source, than set the adjustable voltage source to
+0.4000 volts using your volt meter.
3.
Set the PET-820's ADC mode to low range using programming command code "790#"
4.
Using command code 621#, read the analog voltage at channel 1 and adjust R13, low range adjust shown in Figure
6.2 until the unit speaks the same voltage that is being applied to the input.
5.
Now you are ready to adjust the high range. Re-adjust the voltage source to +4.000 volts or as close as you can.
6.
Set the PET-820 ADC mode to high range using programming command code "791#".
7.
Using command code 621#, read the analog voltage at channel 1 and adjust R11, high range adjust shown in Figure
6.2 until the unit speaks the same voltage that is being applied to the input.
8.
Re-set the PET-820's ADC mode to the original range and re-connect all of the analog signals. This completes the
procedure