Sampling rate for MCC 128 / MCC 118 when using all channels simultaneously

[Anas]

Hello, 

I am looking to buy ADCs that are raspberry pi compatible and am interested in these specific models : MCC 128 / MCC 118. I would like to use this ADCs to convert signals comming from a photodetector array.

In the datasheet the sample rate is listed at 100 Ks/s, but then scrolling down further I found "Conversion time, per channel: 8 µs", does this mean that when using 8 channels simultaneously, the maximum sampling rate is divided by 8, meaning that for 8 channels simultaneously the sample rate would be ~10Ks/s?

Additionally, do you have similar products that have more I/O channels?

Thanks in advance!

[Fausto]

Hello @Anas.

The analog input channels for both the MCC 118 and MCC 128 are multiplexed prior to reaching the A/D converters.  For a single DAQ HAT board, the maximum throughput is 100 kS/s.  If you select 5 analog input channels, then each channel has an effective throughput of 20 kS/s.  When using multiple MCC DAQ HATs, on a Raspberry Pi module, the maximum throughput rate is up to 320 kS/s aggregate.  If you use four MCC DAQ HAT boards (mix of MCC 118 and MCC 128) and select eight single-ended channels on each board, for a total of 32 channels, then the maximum effective throughput of each channel is 10 kS/s.

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

https://mccdaq.github.io/daqhats/_static/esmcc118.pdf

https://mccdaq.github.io/daqhats/overview.html#mcc-128

https://mccdaq.github.io/daqhats/_static/esmcc128.pdf

 

Regards,

Fausto