Adlink USB-1210 User Manual download pdf (Page 50)

40 Operation & Calibration

FPGA. Loading calibration constants entails loading the values of

TrimDACs firmware stored in the onboard EEPROM.

Dedicated space for storing calibration constants is provided in the

EEPROM. In addition to the bank of factory calibration constants,

there is one user-utilization bank, allowing loading of the Trim-

DACs firmware values either from the original factory calibration or

a subsequently-performed calibration.

The default calibration constants are loaded from the user-utiliza-

tion bank and are the same as those in the factory calibration bank

if no auto-calibration is performed.

Since measurement and output errors may vary depending on

time and temperature, it is recommended that you calibrate the

USB-1210 module in your existing testing environment, as follows.

3.2.2 Auto-Calibration

USB-1210 auto-calibration utility measures and corrects almost all

calibration errors with no external signal connections, reference

voltage, or measurement devices. The USB-1210 provides

onboard calibration reference to ensure the accuracy of auto-cali-

bration. The reference voltage is measured in the production line

by a digital potentiometer and compensated in the software. The

calibration constant is stored after this measurement.

3.2.3 Saving Calibration Constants

Factory-calibrated constants are permanently stored in a bank of

the onboard EEPROM and cannot be modified. When the device

is recalibrated, the software stores the new constants in a

user-configurable section of the EEPROM. To restore original fac-

tory calibration settings, the software can copy the factory-cali-

brated constants to the user-configurable section of the EEPROM.

When auto-calibration is complete, the new calibration constants

can be saved to the user-configurable banks in the EEPROM.

NOTE:

The USB-1210 should be warmed up for at least 15 minutes

before initiating auto-calibration

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Adlink USB-1210 User Manual Page 50