If I want to use MCC118 and MCC172 together, Could I set data syncronization between MCC118 and MCC172??

[ahnjs1987]

If I want to use MCC118 and MCC172 together, Could I set data syncronization between MCC118 and MCC172??

MCC118 use clock signal for sampling, and MCC172 also use clock for sampling.

If I set options param to OPTS_EXTCLOCK on mcc118_a_in_scan_start and OPTS_CONTINUOUS on mcc172_a_in_scan_start, Could those devices(MCC118,MCC172) syncronize their sampling period?

[Fausto]

Hello @ahnjs1987.

It is not possible to completely synchronize the MCC 118 and MCC 172, but there are somethings you can try knowing you will have to adjust the data post capture. 

Configure the MCC 172's clock source to be SOURCE_MASTER and set the MCC 118 options parameter to OPTS_EXTCLOCK for the scan.  On the RPi 40-pin header, pin 35 (GPIO19) is the MCC 172's clock bus.  Connnect a wire from pin 35 over to the Clock (CLK) terminal on the MCC 118 board.  You can even connect an external trigger source to the TRIG terminal on each board.  

Note that the MCC 172 clock is programmable for various sampling rates between 200 S/s and 51.2 kS/s, while the MCC 118 has a scan clock up to 100 kS/s.  

https://mccdaq.github.io/daqhats/overview.html#mcc-118

https://mccdaq.github.io/daqhats/overview.html#mcc-172

Lastly, for the MCC 172, due to the nature of the filtering in the A/D converters there is an input delay of 39 samples, so the data coming from the converters at any time is delayed by 39 samples from the current time. This is most noticeable when using a trigger - there will be approximately 39 samples prior to the trigger event in the captured data.  Hence the need to adjust the data post process.

 

Regards,

Fausto

[ahnjs1987]

Hello @Fausto

I configured HW and SW what you suggested.

But there were some problem on reading sampled data.

When I set clock source on MCC172 to SOURCE_MASTER and MCC118 to EXT_CLOCK, it looks like MCC118 get data but MCC172 can't get data.

When I set clock source on MCC172 to SOURCE_LOCAL and MCC118 to internal clock, Both of them works properly.

Is there any guide or example like this?

I attached file what I modified.

upload_forum.c

 

@JRys Could you review my question?

Edited May 16, 2023 by ahnjs1987