How to set gain/offset for 4AD module?
Last modified by Jiahao Lai on 2026/07/27 16:06
Below is gain/offset caculate formula:

Note: the unit of Analog input is μA/mV
For value of "constant" please check the table:

For example, when set channel as 4mA~20mA to 0~1000, the default offset, gain, constant is 4000, 20000, 1000.
If user want to change it as 4mA~20mA to 400~2000, the gain/offset calculation can be done by the following two formulas:
1. 400=(4000-offset)*1000/(gain-offset)
2. 2000=(20000-offset)*1000/(gain-offset)
So the offset and gain should be 0 and 10000

Set BFM21 as 1 to enable Offset/Gain adjustment.
Set BFM22 as 3 to enable Offset/Gain adjustment of channel 1.
Set BFM23 as 0
Set BFM24 as 10000