Probably. This isn't a very straightforward matter and it's not making sense in general. I know what I'm trying to say but it's probably not coming across the way I intended. Apologies for those who are getting confused.
But I stand by it.
And I think I've found what may break this case loose.
@Steve-Mcl, you and I have been right this whole time about MODBUS being 16 bit returns. The spec can't be broken and there isn't a way to get 32 bit values without requesting more registers.
@Lupin_III, you really need to get support to get you a list of MODBUS registers. What you have is not a list of MODBUS registers. You have a list of SAIA data registers. Registers, I might add, that are not intended for MODBUS to use. Let me explain.
I did a little more digging and found a post with the same/similar question here. The answer that came across pointed to a document that, while not specific to your particular module, should apply broadly to much of Saia's inventory as it will be somewhat their standard of implementation. In that document it specifies that the MODBUS registers are mapped to the Saia registers and are not one in the same. You will use the mapped MODBUS address to access the data in the Saia address. The MODBUS address are all setup as 16 bit register counts where one MODBUS address will map to half of a single Saia address, with two MODBUS addresses required to access the full Saia address.
This is how you get your full data.
If you can't get a list of mapped addresses or you somehow hit a dead end, I have another suggestion that came from Steve. Probably without him realizing it.
And I might add you should also see the requested MODBUS addresses being requested for your individual registers. You have the program Saia built to interface with their module. So someone has knowledge on those addresses so that they could build the program. There is one slight caveat...
The unit also communicates over open TCP, which might make it look like you're pulling MODBUS data, but in reality they're just accessing the Saia registers directly through TCP and pulling it, circumventing the MODBUS protocol entirely. At which point, a Wireshark capture will give you absolutely nothing.
Unless you use a TCP request node in Node-Red and bypass the MODBUS node. Which may prove easier than getting the MODBUS information you need.
In any case, you really need that list of MODBUS registers and how they're mapped in order to make this work. Because without it, I don't think you'll get anywhere with MODBUS at all.