PC104-AD16
Page 6
4
Calibration of Analog Channels
It is usually not necessary to calibrate the analog input and output channels via the potentiometers RP1-6 of
the PC104-AD16 placed on the top side of the board (see Figure 1). The extension cards have an accurate
factory setting. In case adjustments or corrections have to be applied, please note the following:
•
Always balance the offset first, then the amplification.
•
Input and output channels have to be recalibrated for each measuring range. Only the NextView
®
meas-
urement software automatically balances the offset differences between the individual measuring ranges.
4.1
Analog Inputs
In order to recalibrate the analog input channels, an accurate reference voltage between 5V and 9V in con-
junction with a program that shows the applied voltage (e.g. NextView
®
4 Demo, v4.2) are needed. Repeat
the following procedures until both displays show the same voltage:
•
Short-circuit the input channel and set the offset potentiometer RP1 until the display shows 0V.
•
Undo the short circuit and apply the known reference voltage. Set the amplification potentiometer RP3
until the display shows exactly the reference voltage.
4.2
Analog Outputs
In order to recalibrate the analog output channels, a precision multimeter (resolution >12 bit) and a program
which can apply a defined voltage to an analog channel (e.g. NextView
®
4 Demo, v4.2) are needed. Repeat
the above procedures until both displays show the same voltage:
•
Set the analog output channel to 0V in the program and connect the multimeter with the corresponding
output channel: adjust the offset potentiometer (AOut 1: RP2; AOut 2: RP5) until the multimeter displays
0V.
•
Set 9.9V for the analog channel in the program: set the amplification potentiometer (AOut 1: RP4; AOut
2: RP6) in such a way that the multimeter displays 9.9V.
