4040A/B: Programmatically Retrieving DAC Value after Boot

[gtolentino]

This post applies to all serial numbers of both the TEGAM 4040A and 4040B. After cycling power to the 4040, the unit will reset to its default offset DAC value of 0x7FFF (decimal 32767). This equates to a DC offset of 0.00 V. However, a programmatic request sent to the 4040 for the current DAC setting will return a value of 0xFFFF (decimal 65535), or +1.2 VDC. This condition will persist until a DAC value has been sent to the 4040, after which the unit will respond correctly to all DAC value requests.

To avoid this issue, it is recommended to send a DAC value to the 4040 at system start-up. The actual DAC value set can be any valid value between 0x0000 and 0xFFFF that is appropriate to your application, or 0x7FFF to retain the default setting. The 4040 will then respond correctly to all subsequent DAC value requests.

If you have any questions or comments about this post, or would like further information about any of our test, measurement, and calibration products, please visit us at http://www.tegam.com, call us at 800-666-1010, or email us at sales@tegam.com.