Good day. I have some legacy code I am working with to read an SSI absolute linear encoder. The code works fine on a ni-9178 cDAQ chassis. However it errors and does not work on a ni-9189 chassis.
The code uses a counter pulse to trigger another counter which is used for the time sourse for the pulses. i.e. every trigger output x pulses for the clock to the encode and read the pulses back from the encoder as data. the cards used are an ni-9491 for the output clock pulses and a 9411 for the incoming data pulses. I have attached the VI. This runs just fine on the ni-9178. When run on the ni-9189, the task that is writing the output clock pulses throws error -200621 "Onboard device memory underflow. Because of system and/or bus-bandwidth limitations, the driver could not write data to the device fast enough to keep up with the device output rate.
Reduce your sample rate. If your data transfer method is interrupts, try using DMA or USB Bulk. You can also reduce the number of programs your computer is executing concurrently."
So far, going through all available documentation on the 2 cDAQs, I cannot see a difference in specs where the 9189 would not be able to perform this function exactly like the 9178.
Any insight here would be super cool.
