Unable to read status (register) from the device

[parthibunn]

    ModbusInput modbusInput = new ModbusInput(ipAddress, BARRIER_PORT);
    ModBusService modBusService = new ModBusService(modbusInput);
    //Get the barrier operation based on the request type UP | DN | FR | UF
    BarrierOperation barrierOperation = modBusService.getBarrierOperation("UP");
    //Send request to barrier to update the barrier operation
    boolean isSuccess = modBusService.sendOperation(barrierOperation);
    LOG.info("Barrier status - " + isSuccess);

public boolean sendOperation(BarrierOperation barrierOperation) { boolean result=false; try { modbusInput.setQuantity(barrierOperation.getCode()); System.out.println("BS Status before - " + iModbusExecutor.readHoldingRegister(modbusInput)); result = iModbusExecutor.writeSingleRegister(modbusInput); System.out.println("BS Status after - " + iModbusExecutor.readHoldingRegister(modbusInput)); return result; } catch (Exception ex) { log.error("Exception at sendOperation : ", ex); return result; } }

public boolean readHoldingRegister(ModbusInput modbusInput) throws Exception { ModbusTCPMaster master = getInstance(modbusInput.getIpAddress(), modbusInput.getPort()); try { master.connect(); InputRegister[] inputRegisters = master.readMultipleRegisters(modbusInput.getRegisterAddress(), 8); for(int i=0;i<inputRegisters.length;i++) { log.info("readHolding - " + inputRegisters[i].getValue()); log.info("readHolding - " + inputRegisters[i].toBytes().toString()); } master.disconnect(); return true; } catch (Exception e) { log.info("Cannot connect to slave - " + e.getMessage()); return false; } }

Basically trying to find the change in status/register value before and after write operation. But the values printed are the same

I must be able to retrieve the device status at any point

Any help would be greatly appreciated. Thanks in advance

[steveohara]

I can't see that you're doing anything wrong here but then I don't know the intricacies of your Barrier controller. I nearly all cases, this is an issue with your slave and the way it expects you to write to a register and then read it back. There are plenty of examples in the tests of doing this if you want to take a look there.

[parthibunn]

@steveohara Thanks for your response. Yes. There is nothing wrong in the code. It was my wrong understanding that caused the issue