Experimental Physics and
Industrial Control System

Christian Pauly via Tech-talk <tech-talk at aps.anl.gov> · Tue, 14 Feb 2023 18:38:40 +0100

Hi folks

I am trying hard to set up a Raspberry running an EPICS IOC for a Delta

VFD motor driver / frequency inverter. The device is controlled via

modbus, using a large set of individual 16bit integer read/write

registers for configuration, and few more registers for control.

At the moment it is configured to talk Modbus ASCII via RS485, and with

a simple Python program using minimalmodbus-lib i can talk to the

controller.

Now i started with a fresh EPICS 3.15.7 base, (in ~/EPICS/base) and

installed ASYN-R4-43 (~/EPICS/modules/asyn-R4-43) and modbus

(~/EPICS/modules/modbus_R3-2).

I initiated a new application ~/EPICS/projects/FUcontrol,

ran "makeBaseApp.pl -t example FUcontrol", "makeBaseApp.pl -i -t example

FUcontrol" - and thats basically it.

And now i am stuck how to include modbus (includes / libs / dbd files)

into my exampleApp.

I kind of managed to include ASYN already by adding
  ASYN=... to the RELEASE file

and to the Makefile:
  FUcontrol_LIBS += asyn

In my ioc startup st.cmd i can run the commands
drvAsynSerialPortConfigure("RS485", "/dev/ttyUSB0", 0, 0, 0)
to configure the interface.

But if i add
modbusInterposeConfig("RS485",2,1000,0)

i get an error on startup claiming that modnusinterposeconfig can not be

found.

So:

Is there any simple step-by-step instructions how to add modbus to an

existing ioc application ?

I could not find anything "simple" in the documentation. I saw the

examples which come with modbus, but all these already look quite

complicated to me...

Or any good advise on how to continue from here ?

Thanks for any help !

Christian