Data Translation DT300 Series, User Manual

Page: 120 / 164

Chapter 8
120
Calibrating the Analog Input Subsystem
To calibrate the analog input circuitry, you need an ex9.3750 V reference (precision
voltage source). Using an ex9.3750 V reference provides an accuracy of approximately
±3 LSB for the DT321 and DT322 boards and ±1 LSB for remaining DT300 Series boards.
You can also choose to calibrate the analog input circuitry automatically or manually;
auto-calibration is the easiest to use and is the recommended calibration method.
The following sections describe how to configure for calibration using either of the supported
references and how to calibrate the analog input circuitry automatically and manually.
Configuring for an External Reference
To calibrate the analog input circuitry using an ex9.3750 V reference, do the following:
1. Connect Analog In 0 (TB1) to the positive side of the precision voltage source.
2. Connect Analog In 0 Return (TB2) to the negative side of the precision voltage source.
3. Connect Analog In 0 Return (TB2) to Analog Ground
(TB18).
4. Connect Analog In 1 (TB3) to Analog In 1 Return (TB4) and to Analog Ground (TB18).
To calibrate the analog input circuitry automatically, continue on page 120 ; to calibrate the
analog input circuitry manually, continue on page 121 .
Using the Auto-Calibration Procedure
To calibrate the analog input subsystem automatically, do the following:
1. From the main menu of the DT300 Series Calibration Utility, click Configure , and then
Board .
2. Select the name of the DT300 Series board to configure from the combo box, and then click
OK .
3. From the main menu of the DT300 Series Calibration Utility, click Calibrate , and then
A/D .
4. In the Auto Calibration box, click Go .
The bipolar (zero and full-scale) and unipolar (zero and full-scale) ranges are automatically
calibrated.
5. Click Quit when you are finished calibrating the analog input circuitry.
Once you have finished this procedure, continue with “Calibrating the Analog Output
Subsystem” on page 123 .