your opinion please

hi all,

I have a machine that has a PC reading registers every 100ms from the PLC over MODBUS

is this ok ?

do you think it is a good idea to do so ? will this damage the serial port on the PC/PLC ?

thanks

Farid said:

is this ok ?

Click to expand...

If it meets your requirements, yes.

Farid said:

do you think it is a good idea to do so ?

Click to expand...

If it meets your (or your customer's) requirements, yes.

Farid said:

will this damage the serial port on the PC/PLC ?

Click to expand...

No.

Dan

Hi Farid,
One thing I think you should check is that your PC software is intelligent enough to make sure that it doesn't send the next Modbus request to the PLC before the PLC is finished replying to the last request. If the PC didn't respect this, it would get garbled messages I think, and have to re-try needlessly.
Other than that, as Dan commented earlier, if you or your customer actually needs this fast update, then by all means use it; it shouldn't slow down the PLC, as it probably doesn't give a high priortiy to replying to Modbus requests. I think rather that it would solve logic first, then devote any spare time to checking the Modbus port. Nor would it harm your PC, as today's PCs are much too quick to be burdened by mere serial communications.
Hope this helps,
Kind regards,
Roger.