Re: Modbus Module issue

[Luis Alberto De Sousa Moreira via Tech-talk <tech-talk at aps.anl.gov>]

    Hi Gabriel,
    The firewall seems to be the culprit, but I added rules for the
    application. I also just done a test where I disabled the firewall
    and I get the same result.
    
D:\FalconDev\EPICS\modbus\iocBoot\iocTest>..\..\bin\windows-x64-mingw\modbusApp.exe
    BPS_Beck.cmd
    # BPS_Beck.cmd
    # Just testing the modbus module with my BPS Beckhoff PLC.
    # 1. Cleanly lock network routing automatically at boot
    epicsEnvSet("EPICS_CA_ADDR_LIST", "10.136.0.255")
    epicsEnvSet("EPICS_CA_AUTO_ADDR_LIST", "NO")
    epicsEnvSet("EPICS_CAS_INTF_ADDR_LIST", "10.136.0.34")
    # gvl.mb_Input_Registers[10] := GVL.d_setpoint_T1;              //
    T1                   mS
    # gvl.mb_Input_Registers[11] := GVL.d_setpoint_TRamp1;  // Ramp1   
                uS
    # gvl.mb_Input_Registers[12] := GVL.d_setpoint_v1;              //
    V1                   10V
    # gvl.mb_Input_Registers[13] := GVL.d_setpoint_T2;              //
    T2                   mS
    # gvl.mb_Input_Registers[14] := GVL.d_setpoint_TRamp2;  // Ramp2   
                uS
    # gvl.mb_Input_Registers[15] := GVL.d_setpoint_V2;              //
    V2                   10V
    # gvl.mb_Input_Registers[16] := GVL.d_setpoint_T3;              //
    T3                   mS
    # gvl.mb_Input_Registers[17] := GVL.d_setpoint_TRamp3;  // Ramp3   
                uS
    # gvl.mb_Input_Registers[18] := GVL.d_setpoint_V3;              //
    V3                   10V
    # gvl.mb_Input_Registers[19] := GVL.d_setpoint_pulseLength;     //
    PulseLength  S /mS
    # gvl.mb_Input_Registers[20] := GVL.d_setpoint_TRampDown;       //
    RampDown             uS
    dbLoadDatabase("../../dbd/modbusApp.dbd")
    modbusApp_registerRecordDeviceDriver(pdbbase)
    # Get the connection going
    drvAsynIPPortConfigure("BPS_Beck", "10.136.0.30:502", 0, 0, 0)
    2026/07/24 09:32:59.953 BPS_Beck -1 autoConnect could not connect:
    Can't connect to 10.136.0.30:502: Unknown error
    # drvAsynIPPortConfigure("BPS_Beck", "8.8.8.8:8080", 0, 0, 0)
    modbusInterposeConfig("BPS_Beck", 0, 5000, 0)
    asynSetOption("BPS_Beck",0, "disconnectOnReadTimeout", "Y")
    #
=========================================================================
    # Configure Modbus Drivers Memory Blocks
    #
=========================================================================
    # Syntax:
    # drvModbusAsynConfigure("portName", "tcpPortName", slaveAddress,
    modbusFunction, modbusStartAddress, modbusLength, dataType,
    pollMsec, "plcType")
    # drvModbusAsynConfigure("modbusPortName", "asynPortName",
    slaveAddress, modbusFunction, startAddress, length, dataType,
    pollMsec, "plcType")
    # Read Coils (Function Code 1)
    # Reads 16 binary bits starting at offset 0, polling every 200
    milliseconds.
    # drvModbusAsynConfigure("READ_COILS", "PLC_NET", 0, 1, 0, 1, 0,
    200, "OldPLC")
    # Write Coils (Function Code 5)
    # Configures a write-only path for coils. pollMsec is 0 because
    writes are instantaneous.
    # drvModbusAsynConfigure("WRITE_COILS", "PLC_NET", 0, 5, 0, 1, 0, 0,
    "OldPLC")
    # Reads 11 read-only 16-bit registers starting at offset 10, polling
    every 500 milliseconds.
    # dataType=0 specifies standard 16-bit unsigned integers (UINT_16).
    drvModbusAsynConfigure("READ_INPUTS", "BPS_Beck", 1, 4, 10, 11, 0,
    500, "Beckhoff")
    # Read Holding Registers (Function Code 3)
    # Reads 1 read/write 16-bit register starting at offset 0, polling
    every 500 milliseconds.
    # dataType=0 specifies standard 16-bit unsigned integers (UINT_16).
    # drvModbusAsynConfigure("READ_HOLDING", "PLC_NET", 0, 3, 0, 1, 0,
    500, "OldPLC")
    # Block E: Write Holding Registers (Function Code 6)
    # Configures a write-only path for single registers. pollMsec is 0
    for on-demand writing.
    # drvModbusAsynConfigure("WRITE_HOLDING", "PLC_NET", 0, 6, 0, 1, 0,
    0, "OldPLC")
    # Enable ASYN_TRACEIO_HEX on octet server
    # asynSetTraceIOMask("BPS_Beck",0,4)
    # Enable ASYN_TRACE_ERROR and ASYN_TRACEIO_DRIVER on octet server
    # asynSetTraceMask("BPS_Beck",0,9)
    dbLoadRecords("../../db/BPS_Beck.db")
    iocInit
    Starting iocInit
############################################################################
    ## EPICS R7.0.10
    ## Rev. 2026-07-01T08:47+0200
    ## Rev. Date build date/time:
############################################################################
    2026/07/24 09:33:00.992 drvModbusAsyn::doModbusIO port READ_INPUTS
    error calling writeRead, error=asynManager::queueLockPort
    queueRequest failed: port BPS_Beck not connected, nwrite=0/6,
    nread=0
    iocRun: All initialization complete
    epics>
    
    Kind Regards
                     Luis

On 23/07/2026 16:24, Gabriel Fedel wrote:

Hi Luis,

Couldn't the firewall be blocking  the EPICS application ? 

Best Regards 

Gabriel

---

From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Luis Alberto De Sousa Moreira via Tech-talk <tech-talk at aps.anl.gov>
Sent: Thursday, July 23, 2026 3:59 PM
To: Mark Rivers <rivers at cars.uchicago.edu>; tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: Modbus Module issue

 

Hi Mark,
My other application is using the Modbus protocol, I used it to do the
initial testing on my system.
I tried the telnet command from my MSYS2 environment and it can connect...

telnet 10.136.0.30 502
Trying 10.136.0.30...
Connected to 10.136.0.30.
Escape character is '^]'.

Kind Regards
                   Luis

On 23/07/2026 15:31, Mark Rivers wrote:
> telnet 10.136.0.30 502

--
Luis Moreira
EPFL SB SPC-II, PPH241 (Batiment PPH) Station 13
CH-1015 Lausanne, Switzerland
Tel.    (+41) 21 693 58 37
E-Mail  luis.moreira at epfl.ch

-- 
Luis Moreira
EPFL SB SPC-II, PPH241 (Batiment PPH) Station 13
CH-1015 Lausanne, Switzerland
Tel.    (+41) 21 693 58 37
E-Mail  luis.moreira at epfl.ch