Hi,
I have a DAB evoplus small pump

I used a LAN cable cat 6a from pump (A,B and ground connector) to USB-RS485 converter, connected to raspberry Pi 3:

I want to read/write registers modbus for controlling pump.
In codesys software, I see a error: a red/yellow pulse triangle (in slave_modbus_porta_COM):

and the code don't work. Why ?
Do you have any solution?

Hi,
did you modify this USB converter to the plc configuration file?
sudo nano /etc/CODESYSControl_User.cfg

[SysCom]
Linux.Devicefile=/dev/ttyUSB

cheers
plcmax

yes.
this is my Codesys configuration file:

[SysFile]
FilePath.1=/etc/, 3S.dat
PlcLogicPrefix=1
[CmpSettings]
FileReference.0=SysFileMap.cfg, SysFileMap
FileReference.1=/etc/CODESYSControl_User.cfg
[_]
Linux.DisableFpuOverflowException=1
Linux.DisableFpuUnderflowException=1
Linux.DisableFpuInvalidOperationException=1
[CmpBACnet]
IniFile=bacstacd.ini
[CmpWebServer]
ConnectionType=0
[CmpOpenSSL]
WebServer.Cert=server.cer
WebServer.PrivateKey=server.key
WebServer.CipherList=HIGH
[SysMem]
Linux.Memlock=0
[CmpCodeMeter]
InitLicenseFile.0=3SLicense.wbb
[SysEthernet]
Linux.ProtocolFilter=3
[CmpSchedule]
ProcessorLoad.Enable=1
ProcessorLoad.Maximum=95
ProcessorLoad.Interval=5000
[SysCom]
Linux.Devicefile=/dev/ttyUSB
portnum := COM.SysCom.SYS_COMPORT1;

Hi,
I would recommend to move

[SysCom]
Linux.Devicefile=/dev/ttyUSB
portnum := COM.SysCom.SYS_COMPORT1;

to the /etc/CODESYSControl_User.cfg if this is 3.5SP11 version.
(because there is already a section for this)
If done, which channels/function codes to read did you add to your modbus slave?

BR
Edwin

[SysCom]
Linux.Devicefile=/dev/ttyUSB
portnum := COM.SysCom.SYS_COMPORT1;

from /etc/CODESYSControl.cfg to /etc/CODESYSControl_User.cfg

This is screenshoot for function:

and this is error in ModbusGeneric SerialSlave (pulse from "bus failure" to "not running"):

You can download Modbus register for DAB Evoplus small pump's from here

ok. Solved !
The Rs485-usb converter was broken.
With new converter is all ok !