So, I've finally built a switch list that exceeds the memory size of the switch and I'm getting error -1074118651. Is there maybe a way to stream the switches in to avoid the memory limit?
Solved! Go to Solution.
Hi! The error -1074118651 refers to the maximum number of bytes that can be sent to the memory of the PXI 2536. Connecting and disconnecting a single relay will take 8 bytes, although there are other factors to consider such as topology, and routes which take more than one switch.
There is not really a way of increasing the memory size of the switch, or compressing the size of the scan list. If you have a large scan list, the best workaround would be to split it up into multiple scan lists and run them one at a time.
As a future product suggestion it would be nice if there was a fifo onboard the switch. That way you could preload switch actions the same way you stream AO data in DAQmx
I'm hoping you will be able to help with this issue, because I can't runt two different switch lists.
When you say that a disconnect + connect takes up 8 bytes, what memory are you referring to? It would be super helpful to know the maximum amount of memory and how to calculate it, but I can't seem to find it anywhere. I'm assuming it's not the txt file you load in to the switch that matters.
Each connection or disconnect you make in the Scan List (Text file) that you load to your switch takes 8 bytes of memories. Specifying 100 connections will map to 800 bytes, and 1000 connections will be 8,000 bytes.
You can find the memory available by examining the Letter of Volatility for the device. For example, the PXI-2535 Letter of Volatility has 128KB of SRAM. If you divide that by 8 bytes per connection, you can create a scanlist with a maximum size of (128,000 Bytes)/(8 Bytes/Connection) = 16,000 connections.
Thank you so much, I didn't know that the letter of volatility was where I should look for it. Very helpful 🙂
For anyone that is experiencing something similar, the way I solved it was disable BBM and gray code my switch list. This helps in reducing the number of switches.