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| <== Date ==> | <== Thread ==> |
|---|
| Subject: | modbus reading arrays of floats |
| From: | "Pearson, Matthew via Tech-talk" <tech-talk at aps.anl.gov> |
| To: | "tech-talk at aps.anl.gov" <tech-talk at aps.anl.gov> |
| Date: | Thu, 19 Oct 2023 22:12:39 +0000 |
|
Hi, I have a device which supports reading arrays of floats (IEEE Float32) over Modbus/TCP.
Am I right in thinking that currently this isn’t supported by the Asyn modbus support? It seems to support arrays of ints, but not floats.
Interestingly, this almost works: record(waveform, "$(P)$(R)TCA") { field(FTVL, "ULONG") field(DTYP, "asynInt32ArrayIn") field(INP, "@asyn($(PORT)8w4,2064,1)FLOAT32_LE") …. } By specifying the datatype to be FLOAT32_LE, the modbus driver correctly converts the byte data to floats, but the waveform only gives me the integer part of the number. So as a work-around I’ve implement multiple reads, one per Float32. This works fine, and I’ll likely stick with it. However, is there a smarter workaround? For example, can I read the data as a block of Ints, then convert to IEEE Float32 in the database (without writing a subroutine)? Cheers, Matt |