Communication Issue with Varian V-70 Turbo Pump Controller

Hey All,

As a prelude, this issue may likely not be VISA related so much as related to either my physical connections or my misunderstanding of the product datasheet. Any help would be appreciated, but I can also reach out to the manufacturer if needed.

I am trying to command a Varian V-70 Turbo Pump controller from my host Windows 10 PC via a USB to RS232 adapter cable. My software configuration is as follows:

• NI VISA 19.0
• LabVIEW 2017 SP1 f3

I have tried to communicate with this device in both LabVIEW and in a VISA test panel in NI MAX. In both cases, I get the classic timeout error:

Attached is the manual for the device. Pages 74 and 75 are of interest, as they outline the physical connections and communication setup in software. Below are two relevant snippets:

Communication Port

Command and Response

I have ensured my VISA session is configured with the correct format (baud rate, data and stop bits, parity) and have also tired timeouts of various lengths. In addition, I have followed the manuals instructions for ensuring the controller is in the proper mode to accept commands via RS232. Based on everything I have tried, the questions/thoughts I have are as follows:

Questions:

1. Does the first image imply in any way that a USB to RS232 converter could cause issues? The phrase "The external cable (not supplied) between the host computer and the controller doesn’t require any crossed wires so that the signal are connected correctly." is confusing to me.
2. If (1) is the case, maybe I actually need to be using NI Serial 19.0 with a RS232 cable instead of a USB to RS232 adapter?
3. To me, image 2 implies the commands are literally just the characters "A, B, C..etc" I am not familiar with the concept of a CRC, but some googling has explained the concepts yet I am unsure how this affects how I format my actual messages.
4. To build off of (3), do I need to be formatting my commands as Request + CRC or is the CRC handled by the nature of VISA and the setup of my VISA session?
5. I am not familiar with USB RAW mode, but maybe I should be using that?

Articles used:

Error -1073807339 VISA Read or Write Timeout

How Can I Communicate With a Device Using NI-VISA USB RAW Mode?

Thanks for any help!