Experimental Physics and
Industrial Control System

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