Calibration Procedures
Chapter 4
AT-MIO-16 User Manual
4-8
© National Instruments Corporation
•
For analog output channel 1:
a. Connect the voltmeter between DAC1OUT (pin 21 on the I/O connector) and AOGND
(pin 23).
b. Set the analog output channel to -10 V by writing -2,048 to the DAC.
c. Adjust trimpot R3 until the output voltage read is -10 V
±
2.44 mV, that is, between
-10.00244 V and -9.99756 V.
2. Adjust the Analog Output Gain
To adjust the analog output gain, measure the output voltage generated with the DAC set at
positive full scale (2,047). This output voltage should be V
+fs
±
1
/
2
LSB. For bipolar output,
V
+fs
= +9.99512 V, and
1
/
2
LSB = 2.44 mV.
•
For analog output channel 0:
a. Connect the voltmeter between DAC0OUT (pin 20 on the I/O connector) and AOGND
(pin 23).
b. Set the analog output channel to +9.99512 V by writing 2,047 to the DAC.
c. Adjust trimpot R5 until the output voltage read is +9.99512 V
±
2.44 mV, that is, between
9.99268 V and 9.99756 V.
•
For analog output channel 1:
a. Connect the voltmeter between DAC1OUT (pin 21 on the I/O connector) and AOGND
(pin 23).
b. Set the analog output channel to +9.99512 V by writing 2,047 to the DAC.
c. Adjust trimpot R4 until the output voltage read is +9.99512 V
±
2.44 mV, that is, between
9.99756 V and 9.99268 V.
Unipolar Output Calibration Procedure
If your analog output channel is configured for unipolar output, which provides an output range
of 0 to +10 V, calibrate your board by performing the following procedure.
1. Adjust the Analog Output Offset
To adjust the analog output offset, measure the output voltage generated with the DAC set at
zero. This output voltage should be V
-fs
±
1
/
2
LSB. For unipolar output, V
-fs
= 0 V, and
1
/
2
LSB = 1.22 mV.