Acquisition with BMXAMI0810

[sarathkumarks07]

I want to acquire a 20Hz sine signal using BMXAMI0810 module. I am using all available 8 channels on the module. This module is using in a MAST task running periodically every 20ms.

1.Is it possible to accurately measure the signal using this module.?

2. What is the cutoff frequency of analog filter implemented in the hardware?

[ciupol · Accepted solution]

I am not an expert on this but your numbers tell me that it will be hard to recreate your sine signal. PLC scans IO only once per scan so for you it would be every 20ms. With 20Hz signal the period is 50ms so you will get maximum 2 to 3 samples per scan.

As far as filter goes, if you select 0 in channel configuration there will be no filtering applied.

For the module itself from the manual it looks like the minimum acquisition time is 1ms + 1ms for each channel used so if you use all the channels the time would be 9ms. But once again PLC only reads from the module once per scan.

On top of that it is important if the module is in local or remote rack. If remote is it ethernet or coax. Also for the remote the timing on the IO bus can be set.

[Hennie_Smith · Accepted solution]

Hi. You will have to scan the card on a Fast task with max 5ms to get meaningful result but that would limit you to 4 channels (1ms + 1ms per channel). What exactly do you need to measure on this signal? If it is the amplitude I would put it though a bridge rectifier before the card and in software take the voltage drop of the bridge into account.