Experimental Physics and
Industrial Control System

Christian Pauly via Tech-talk <tech-talk at aps.anl.gov> · Wed, 15 Feb 2023 01:56:33 +0100

Great, thanks for the quick help !
Now it works, the ioc starts and is running.

But now i am stuck with defining a record using the modbus interface.

As a simpe start, I would like to read a single word (int16) from a

given address 0x2103 of master device with id=1, using modbus read

function type 3.

the relevant part of my st.cmd at the moment looks like this:

drvAsynSerialPortConfigure("RS485", "/dev/ttyUSB0", 0, 0, 0)
asynSetOption("RS485",0,"baud","9600")
asynSetOption("RS485",0,"parity","none")
asynSetOption("RS485",0,"bits","7")
asynSetOption("RS485",0,"stop","2")
asynOctetSetOutputEos("RS485",0,"\r\n")
asynOctetSetInputEos("RS485",0,"\r\n")
modbusInterposeConfig("RS485",2,1000,5)
drvModbusAsynConfigure(IN_int,"RS485",1,3,-1,1,UINT16,1000,0)
asynSetTraceIOMask("RS485",0,4)

## Load record instances
dbLoadTemplate "FUrecords.db"

But how do i have to define the ai(?)-record in FUrecords.db now, to

read a single word from the given address 0x2103 using the IN_int

function as defined above ?

without using template- and substitution files like in all examples i

found so far ?? (for sure that is the more clever way, but before i try

to understand that part i would like to have a running example first)

Thanks again for any help !

Christian

On 2/14/23 20:23, Pierrick M Hanlet via Tech-talk wrote:

I almost forgot, you'll also need to add modbus to your
$TOP/configure/RELEASE file (assuming that you have the modbus module).
This may not be precisely worded, but when adding a module, you need to
define its path in $TOP/configure/RELEASE and then
add the modules (lib / dbd) to the $TOP/xxxApp/src/Makefile.
Cheers,
Pierrick

On 2/14/23 13:02, Pierrick M Hanlet via Tech-talk wrote:

Hi Christian,
You will also need to add some things to your xxxApp/src/Makefile:
- xxx_DBD+=modbusSupport.dbd
- xxx_DBD+=drvAsynSerialPort.dbd
- xxx_LIBS+=modbus

I think that this should do it for you.
Good luck,
Pierrick

On 2/14/23 11:38, Christian Pauly via Tech-talk wrote:

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

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System