--- In "Yan Seiner" <> wrote:
>
> ISTR that the ModbusRTU spec requires no more than 2.5 character
> spacing between query and reply. I ended up using threads to make
> sure that I didn't lose the response (a write thread, a listen
thread,
> and a watchdog thread.) You can get my modbus library at
> <http://www.seiner.com/ts7000/modbus-0.0.2.tar.gz>
>
My reading of Modbus RTU is that you need to add a space of 4?
character times between query and response (it can be much larger
than this for most devices). However a Modbus RTU device sees a 2.5
character time space as the end of packet - therefore it is important
to send the whole response at one time.
I'm not sure how the serial driver handles the sending of the packet,
but tne worst it should be would be the need to resend the packet
when the response gives a CRC or other error (with the associated
update delay which may be critical.
Regards,
PJE
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