Sampling rate

[fishywisky]

Hello,

I am an intern at my company, and my task is to create a testing workbench for our main product. For this purpose, I was provided with an MCC DAQ USB 1808 X. However, the number of available channels was insufficient, so they acquired a USB 1608GX-2OA, allowing me to use 16 pins in single-ended mode.

A small problem has arisen: I need to sample my incoming signal at roughly 200KS/s. To acquire these signals, I use the MCCULW function "ul.a_in_scan()" where I specify my 16 channels after configuring them in single-ended mode. To my surprise, I encountered the error:

"Active DAQ device: USB-1608GX-2AO (219D2A1) 'Starting scan on analog input ports 0 to 13 ... Error 24: Invalid sampling rate." with a samling rate at 177000.

Here is my question: Am I misunderstanding the sampling rate capabilities? Is the 500KS/s rate divided by the number of channels I am using? How can I bypass this issue, if possible?

Thank you for your assistance.

[Fausto]

Hello @fishywisky.

The USB-1808X supports an ADC per channel with a maximum sampling rate of 200 kHz/channel.

The USB-1608GX-2AO has one ADC and the analog input channels are multiplexed; the maximum aggregate sampling rate is 500 kHz.  For 16 analog input channels, the maximum sampling rate per channnel is 500 kHz / 16 = 31,250 Hz/channel.  The USB-1608GX-2AO does not satisfy your application's requirement of 200 kHz/channel.

Consider using two USB-1808X devices.  Connect the 'Input Scan Clock Output' of one device to the 'Input Scan Clock Input' of the second device to sync both devices; resulting in 16 analog input channels.

Regards,

Fausto

[fishywisky]

Hello Fausto,

Thank you alot for your reply.