PCI-82x Series Cards
Multifunction Boards
User Manual, Ver. 1.5, Jan. 2017, PMH-024-15, Page: 61
7
Calibration
Each PCI-822/826 Series card is already fully calibrated when shipped from the factory, including the
calibration coefficients that are stored in the onboard EEPROM, so it is usually unnecessary to
calibrate the board again unless the accuracy is lost. The procedure described below provides a
method that allows the board to be calibrated for a more precise application of voltages within the
system, so that the correct voltages for your field connection can be achieved. This calibration
method ensures that the effects of voltage drops caused by IR loss in the cable and/or the
connector can be eliminated.
Before beginning calibration, ensure that a precise multi-meter is available. Note that the calibrated
values for the Analog Input/Output channels are stored within three words in the address of the
EEPROM, as shown in the table below.
The calibration values stored in the EEPROM address are as follows:
EEPROM Address
D/A Calibration
CH 0
CH 1
Bipolar
-10 V
0
8
+10 V
1
9
Unipolar
+0 V
2
10
+10 V
3
11
Bipolar
-5 V
4
12
+5 V
5
13
Unipolar
+0 V
6
14
+5 V
7
15
EEPROM Address
D/A Calibration
ADC 0
Bipolar
+10 V
16
-10 V
17
Warning:
It is recommended that calibration is
not
performed until the process is fully understood.
Note:
Ensure that a stable calibration source is used. An unstable calibration source will cause
calibration errors and will affect the accuracy of the data acquisition.
