IoT::Modbus

class IModbusMaster

File Information

Library: IoT/Modbus
Package: Generated
Header: IoT/Modbus/IModbusMaster.h

Description

This class defines the interface for Modbus clients.

The interface supports two basic modes of operation:

  • Asynchronous requests: One of the sendXXXRequest() methods is used to send a request to the device. The method returns as soon as the request has been queued to be sent over the wire (actual sending is done in a separate thread). The device's response, is reported asynchronously via an appropriate XXXResponseReceived event. Errors encountered during sending are reported via requestFailed. Modbus exception responses are reported via exceptionReceived. A timeout waiting for the response is reported via the timeout event.
  • Synchronous requests: After sending the request, the method waits for the response from the device and directly returns it to the caller. In case no response is received within the specified timeout, a Poco::TimeoutException is thrown. If an exception message is received from the device, a ModbusException is thrown. If an incomplete or invalid message is received, a Poco::ProtocolException is thrown.

Note that asynchronous and synchronous (blocking) mode cannot be used simultaneously. Calling one of the asynchronous request methods will enable asynchronous mode. Calling one of the synchronous request methods will disable asynchronous mode. Switching to synchronous mode while a response to an asynchronous request is pending will lead to undefined results, including possible mismatch of requests and responses.

In asynchronous operation, requests are associated with a transaction ID, to tell apart multiple concurrent transactions. Transaction IDs are not guaranteed to be unique for subsequent requests. In fact, for Modbus RTU, which does not allow multiple simultaneous requests, the transaction ID will always be zero.

Inheritance

Direct Base Classes: Poco::OSP::Service

All Base Classes: Poco::OSP::Service, Poco::RefCountedObject

Known Derived Classes: ModbusMasterRemoteObject

Member Summary

Member Functions: address, hasTransactionIDs, isA, maskWriteRegister, maxSimultaneousTransactions, pendingTransactions, readCoils, readDiscreteInputs, readExceptionStatus, readFIFOQueue, readHoldingRegisters, readInputRegisters, readWriteMultipleRegisters, remoting__enableEvents, remoting__typeId, reset, sendMaskWriteRegisterRequest, sendReadCoilsRequest, sendReadDiscreteInputsRequest, sendReadExceptionStatusRequest, sendReadFIFOQueueRequest, sendReadHoldingRegistersRequest, sendReadInputRegistersRequest, sendReadWriteMultipleRegistersRequest, sendRequest, sendWriteMultipleCoilsRequest, sendWriteMultipleRegistersRequest, sendWriteSingleCoilRequest, sendWriteSingleRegisterRequest, type, writeMultipleCoils, writeMultipleRegisters, writeSingleCoil, writeSingleRegister

Inherited Functions: duplicate, isA, referenceCount, release, type

Types Aliases

Ptr

using Ptr = Poco::AutoPtr < IModbusMaster >;

Constructors

IModbusMaster

IModbusMaster();

Creates a IModbusMaster.

Destructor

~IModbusMaster virtual

virtual ~IModbusMaster();

Destroys the IModbusMaster.

Member Functions

address virtual

virtual std::string address() const = 0;

Returns the Modbus master address as a string.

hasTransactionIDs virtual

virtual bool hasTransactionIDs() const = 0;

Returns true if the port supports transaction IDs, otherwise false. Currently, only Modbus/TCP supports transaction IDs.

isA virtual

bool isA(
    const std::type_info & otherType
) const;

Returns true if the class is a subclass of the class given by otherType.

See also: Poco::OSP::Service::isA()

maskWriteRegister virtual

virtual void maskWriteRegister(
    Poco::UInt8 slaveAddress,
    Poco::UInt16 referenceAddress,
    Poco::UInt16 andMask,
    Poco::UInt16 orMask
) = 0;

Sends a Mask Write register request to the device and waits for the response.

Throws a Poco::TimeoutException if the device does not respond within the specified timeout. Throws a ModbusException if the device responds with an exception message.

maxSimultaneousTransactions virtual

virtual std::size_t maxSimultaneousTransactions() const = 0;

Returns the maximum allowed number of in-flight requests.

pendingTransactions virtual

virtual std::size_t pendingTransactions() const = 0;

Returns the current number of in-flight requests.

readCoils virtual

virtual std::vector < bool > readCoils(
    Poco::UInt8 slaveAddress,
    Poco::UInt16 startingAddress,
    Poco::UInt16 nOfCoils
) = 0;

Sends a Read Coils request to the device and waits for the response.

Note: due to the wire format of the Modbus protocol, the returned vector will always have a size that is a multiple of 8, and may thus contain up to 7 more values than specified in nOfCoils.

Throws a Poco::TimeoutException if the device does not respond within the specified timeout. Throws a ModbusException if the device responds with an exception message.

readDiscreteInputs virtual

virtual std::vector < bool > readDiscreteInputs(
    Poco::UInt8 slaveAddress,
    Poco::UInt16 startingAddress,
    Poco::UInt16 nOfInputs
) = 0;

Sends a Read Discrete Inputs request to the device and waits for the response.

Note: due to the wire format of the Modbus protocol, the returned vector will always have a size that is a multiple of 8, and may thus contain up to 7 more values than specified in nOfInputs.

Throws a Poco::TimeoutException if the device does not respond within the specified timeout. Throws a ModbusException if the device responds with an exception message.

readExceptionStatus virtual

virtual Poco::UInt8 readExceptionStatus(
    Poco::UInt8 slaveAddress
) = 0;

Sends a Read Exception Status request to the device and waits for the response.

Throws a Poco::TimeoutException if the device does not respond within the specified timeout. Throws a ModbusException if the device responds with an exception message.

readFIFOQueue virtual

virtual std::vector < Poco::UInt16 > readFIFOQueue(
    Poco::UInt8 slaveAddress,
    Poco::UInt16 fifoPointerAddress
) = 0;

Sends a Read FIFO Queue request to the device and waits for the response.

Throws a Poco::TimeoutException if the device does not respond within the specified timeout. Throws a ModbusException if the device responds with an exception message.

readHoldingRegisters virtual

virtual std::vector < Poco::UInt16 > readHoldingRegisters(
    Poco::UInt8 slaveAddress,
    Poco::UInt16 startingAddress,
    Poco::UInt16 nOfRegisters
) = 0;

Sends a Read Holding Registers request to the device and waits for the response.

Throws a Poco::TimeoutException if the device does not respond within the specified timeout. Throws a ModbusException if the device responds with an exception message.

readInputRegisters virtual

virtual std::vector < Poco::UInt16 > readInputRegisters(
    Poco::UInt8 slaveAddress,
    Poco::UInt16 startingAddress,
    Poco::UInt16 nOfRegisters
) = 0;

Sends a Read Input Registers request to the device and waits for the response.

Throws a Poco::TimeoutException if the device does not respond within the specified timeout. Throws a ModbusException if the device responds with an exception message.

readWriteMultipleRegisters virtual

virtual std::vector < Poco::UInt16 > readWriteMultipleRegisters(
    Poco::UInt8 slaveAddress,
    Poco::UInt16 writeStartingAddress,
    const std::vector < Poco::UInt16 > & writeValues,
    Poco::UInt16 readStartingAddress,
    Poco::UInt8 nOfReadRegisters
) = 0;

Sends a Read/Write Multiple registers request to the device and waits for the response.

Throws a Poco::TimeoutException if the device does not respond within the specified timeout. Throws a ModbusException if the device responds with an exception message.

remoting__enableEvents virtual

virtual std::string remoting__enableEvents(
    Poco::RemotingNG::Listener::Ptr pListener,
    bool enable = bool (true)
) = 0;

Enable or disable delivery of remote events.

The given Listener instance must implement the Poco::RemotingNG::EventListener interface, otherwise this method will fail with a RemotingException.

This method is only used with Proxy objects; calling this method on a RemoteObject will do nothing.

remoting__typeId static

static const Poco::RemotingNG::Identifiable::TypeId & remoting__typeId();

Returns the TypeId of the class.

reset virtual

virtual void reset() = 0;

Resets the connection to the bus or device.

sendMaskWriteRegisterRequest virtual

virtual Poco::UInt16 sendMaskWriteRegisterRequest(
    const IoT::Modbus::MaskWriteRegisterRequest & request
) = 0;

Sends a Mask Write Register request.

A response from the device will be reported via the maskWriteRegisterResponseReceived event.

Returns the transaction ID for the request.

sendReadCoilsRequest virtual

virtual Poco::UInt16 sendReadCoilsRequest(
    const IoT::Modbus::ReadCoilsRequest & request
) = 0;

Sends a Read Coils request.

A response from the device will be reported via the readCoilsResponseReceived event.

Returns the transaction ID for the request.

sendReadDiscreteInputsRequest virtual

virtual Poco::UInt16 sendReadDiscreteInputsRequest(
    const IoT::Modbus::ReadDiscreteInputsRequest & request
) = 0;

Sends a Read Discrete Inputs request.

A response from the device will be reported via the readDiscreteInputsResponseReceived event.

Returns the transaction ID for the request.

sendReadExceptionStatusRequest virtual

virtual Poco::UInt16 sendReadExceptionStatusRequest(
    const IoT::Modbus::ReadExceptionStatusRequest & request
) = 0;

Sends a Read Exception Status request.

A response from the device will be reported via the readExceptionStatusResponseReceived event.

Returns the transaction ID for the request.

sendReadFIFOQueueRequest virtual

virtual Poco::UInt16 sendReadFIFOQueueRequest(
    const IoT::Modbus::ReadFIFOQueueRequest & request
) = 0;

Sends a Read FIFO Queue request.

A response from the device will be reported via the readFIFOQueueResponseReceived event.

Returns the transaction ID for the request.

sendReadHoldingRegistersRequest virtual

virtual Poco::UInt16 sendReadHoldingRegistersRequest(
    const IoT::Modbus::ReadHoldingRegistersRequest & request
) = 0;

Sends a Read Holding Registers request.

A response from the device will be reported via the readHoldingRegistersResponseReceived event.

Returns the transaction ID for the request.

sendReadInputRegistersRequest virtual

virtual Poco::UInt16 sendReadInputRegistersRequest(
    const IoT::Modbus::ReadInputRegistersRequest & request
) = 0;

Sends a Read Input Registers request.

A response from the device will be reported via the readInputRegistersResponseReceived event.

Returns the transaction ID for the request.

sendReadWriteMultipleRegistersRequest virtual

virtual Poco::UInt16 sendReadWriteMultipleRegistersRequest(
    const IoT::Modbus::ReadWriteMultipleRegistersRequest & request
) = 0;

Sends a Read Write Multiple Registers request.

A response from the device will be reported via the readWriteMultipleRegistersResponseReceived event.

Returns the transaction ID for the request.

sendRequest virtual

virtual Poco::UInt16 sendRequest(
    const IoT::Modbus::GenericMessage & message
) = 0;

Sends a generic Modbus message.

The caller is responsible for correct formatting of the messages's data field.

This can be used to send Modbus requests not directly supported by the ModbusMaster interface.

A response from the device will be reported via the responseReceived event or a more specific event if the response message type is supported.

Returns the transaction ID for the request.

sendWriteMultipleCoilsRequest virtual

virtual Poco::UInt16 sendWriteMultipleCoilsRequest(
    const IoT::Modbus::WriteMultipleCoilsRequest & request
) = 0;

Sends a Write Multiple Coils request.

A response from the device will be reported via the writeMultipleCoilsResponseReceived event.

Returns the transaction ID for the request.

sendWriteMultipleRegistersRequest virtual

virtual Poco::UInt16 sendWriteMultipleRegistersRequest(
    const IoT::Modbus::WriteMultipleRegistersRequest & request
) = 0;

Sends a Write Multiple Registers request.

A response from the device will be reported via the writeMultipleRegistersResponseReceived event.

Returns the transaction ID for the request.

sendWriteSingleCoilRequest virtual

virtual Poco::UInt16 sendWriteSingleCoilRequest(
    const IoT::Modbus::WriteSingleCoilRequest & request
) = 0;

Sends a Write Single Coil request.

A response from the device will be reported via the writeSingleCoilResponseReceived event.

Returns the transaction ID for the request.

sendWriteSingleRegisterRequest virtual

virtual Poco::UInt16 sendWriteSingleRegisterRequest(
    const IoT::Modbus::WriteSingleRegisterRequest & request
) = 0;

Sends a Write Single Register request.

A response from the device will be reported via the writeSingleRegisterResponseReceived event.

Returns the transaction ID for the request.

type virtual

const std::type_info & type() const;

Returns the type information for the object's class.

See also: Poco::OSP::Service::type()

writeMultipleCoils virtual

virtual void writeMultipleCoils(
    Poco::UInt8 slaveAddress,
    Poco::UInt16 startingAddress,
    const std::vector < bool > & values
) = 0;

Sends a Write Multiple Coils request to the device and waits for the response.

Throws a Poco::TimeoutException if the device does not respond within the specified timeout. Throws a ModbusException if the device responds with an exception message.

writeMultipleRegisters virtual

virtual void writeMultipleRegisters(
    Poco::UInt8 slaveAddress,
    Poco::UInt16 startingAddress,
    const std::vector < Poco::UInt16 > & values
) = 0;

Sends a Write Multiple Registers request to the device and waits for the response.

Throws a Poco::TimeoutException if the device does not respond within the specified timeout. Throws a ModbusException if the device responds with an exception message.

writeSingleCoil virtual

virtual void writeSingleCoil(
    Poco::UInt8 slaveAddress,
    Poco::UInt16 outputAddress,
    bool value
) = 0;

Sends a Write Single Coils request to the device and waits for the response.

Throws a Poco::TimeoutException if the device does not respond within the specified timeout. Throws a ModbusException if the device responds with an exception message.

writeSingleRegister virtual

virtual void writeSingleRegister(
    Poco::UInt8 slaveAddress,
    Poco::UInt16 registerAddress,
    Poco::UInt16 value
) = 0;

Sends a Write Single Register request to the device and waits for the response.

Throws a Poco::TimeoutException if the device does not respond within the specified timeout. Throws a ModbusException if the device responds with an exception message.

Variables

badFrameReceived

Poco::BasicEvent < void > badFrameReceived;

connectionStateChanged

Poco::BasicEvent < const IoT::Modbus::ConnectionState > connectionStateChanged;

error

Poco::BasicEvent < const std::string > error;

exceptionReceived

Poco::BasicEvent < const IoT::Modbus::ModbusExceptionMessage > exceptionReceived;

maskWriteRegisterResponseReceived

Poco::BasicEvent < const IoT::Modbus::MaskWriteRegisterResponse > maskWriteRegisterResponseReceived;

readCoilsResponseReceived

Poco::BasicEvent < const IoT::Modbus::ReadCoilsResponse > readCoilsResponseReceived;

readDiscreteInputsResponseReceived

Poco::BasicEvent < const IoT::Modbus::ReadDiscreteInputsResponse > readDiscreteInputsResponseReceived;

readExceptionStatusResponseReceived

Poco::BasicEvent < const IoT::Modbus::ReadExceptionStatusResponse > readExceptionStatusResponseReceived;

readFIFOQueueResponseReceived

Poco::BasicEvent < const IoT::Modbus::ReadFIFOQueueResponse > readFIFOQueueResponseReceived;

readHoldingRegistersResponseReceived

Poco::BasicEvent < const IoT::Modbus::ReadHoldingRegistersResponse > readHoldingRegistersResponseReceived;

readInputRegistersResponseReceived

Poco::BasicEvent < const IoT::Modbus::ReadInputRegistersResponse > readInputRegistersResponseReceived;

readWriteMultipleRegistersResponseReceived

Poco::BasicEvent < const IoT::Modbus::ReadWriteMultipleRegistersResponse > readWriteMultipleRegistersResponseReceived;

requestFailed

Poco::BasicEvent < const IoT::Modbus::RequestFailure > requestFailed;

responseReceived

Poco::BasicEvent < const IoT::Modbus::GenericMessage > responseReceived;

timeout

Poco::BasicEvent < const Poco::UInt16 > timeout;

writeMultipleCoilsResponseReceived

Poco::BasicEvent < const IoT::Modbus::WriteMultipleCoilsResponse > writeMultipleCoilsResponseReceived;

writeMultipleRegistersResponseReceived

Poco::BasicEvent < const IoT::Modbus::WriteMultipleRegistersResponse > writeMultipleRegistersResponseReceived;

writeSingleCoilResponseReceived

Poco::BasicEvent < const IoT::Modbus::WriteSingleCoilResponse > writeSingleCoilResponseReceived;

writeSingleRegisterResponseReceived

Poco::BasicEvent < const IoT::Modbus::WriteSingleRegisterResponse > writeSingleRegisterResponseReceived;

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