/** Opens a new connection to the slave. */
private void prepareConnection() {
try {
connection = new TCPMasterConnection(address);
connection.setPort(port);
connection.connect();
transaction = new ModbusTCPTransaction(this.connection);
} catch (Exception e) {
log.warning("Opening connection not successful: " + e.getMessage());
}
}
/**
* Read one value of the slave
*
* @param address Address of Memory of value in slave
* @return the read value
*/
public int sendReadRequest(int address) throws Exception {
ReadInputRegistersResponse response = null;
short tmp_value = 0;
try {
ReadInputRegistersRequest request = new ReadInputRegistersRequest(address, 1);
response = (ReadInputRegistersResponse) this.sendRequest(request);
tmp_value = response.getRegister(0).toShort();
if (tmp_value == 0x7FFF) throw new Exception("0x7FFF received - value ignored");
} catch (Exception ex) {
log.warning("Error on reading value: " + ex.getMessage());
throw ex;
}
return tmp_value;
}
/**
* Creates the ModBusWrapper.
*
* @param ip can contain the port information
*/
public ModBusWrapper(String ip) {
int idx = ip.indexOf(':');
// extract port information
if (idx > 0) {
port = Integer.parseInt(ip.substring(idx + 1));
ip = ip.substring(0, idx);
}
try {
address = InetAddress.getByName(ip);
} catch (Exception e) {
log.severe("Failed to create address: " + ip + ";" + e.getMessage());
return;
}
}
/**
* Send a request to JAMod library. Opens and closes the connection each time. Otherwise the TCP
* Stack of the slaves seams to have problems creating a response.
*
* @param request
* @return the response
*/
private ModbusResponse sendRequest(ModbusRequest request) {
if (request == null) return null;
prepareConnection();
ModbusResponse response = null;
transaction.setRequest(request);
try {
transaction.execute();
response = transaction.getResponse();
} catch (Exception e) {
log.warning("Sending request not successful: " + e.getMessage());
}
this.connection.close();
return response;
}
/**
* Write a configuration value to the slave
*
* @param address Address of the configuration value
* @param value Value to be set
* @return true if value received correctly
*/
public boolean sendWriteRequest(int address, int value) {
SimpleRegister reg = new SimpleRegister(value);
try {
WriteSingleRegisterRequest request = new WriteSingleRegisterRequest(address, reg);
WriteSingleRegisterResponse response =
(WriteSingleRegisterResponse) this.sendRequest(request);
if (value != response.getRegisterValue()) {
log.warning("The sent value isn't the same as the received value");
return false;
}
} catch (Exception ex) {
log.warning("Error on writing value: " + ex.getMessage());
return false;
}
return true;
}