Experimental Physics and
Industrial Control System

[email protected] (Touchard Dominique) · Wed, 19 Sep 2007 15:44:19 +0200

Hi,

we are working on/with the Epics modbus tcp driver written by Mark
Rivers. We need to write a 32 bits integer value in a power supply
command control interface.  First we thought to write an asyn32Int
record with the number 6 modbus function.  Immediatly, we saw that the
driver uses the number 6 modbus function which works only on a 16 bits word.

After reading the Modbus Driver Support documentation, we saw that we
have to use a two value length waveform record.

First question : is this correct ?

Second question : do we have to use the gensub record to manipulate
values inside a waveform record ? In this case, is there any example
that shows how to do this ? Could somebody send us an example on this ?

Third question : Is a bad idea to modify the modbus driver in the goal
to write a asyn32Int 32 bits integer record with the  number 16 modbus
function ?

Thanks for your help .

Dominique Touchard.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System