AIAOTest.java

/***
 * Copyright 2002-2010 jamod development team
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ***/

package net.wimpi.modbus.cmd;

import java.net.InetAddress;

import net.wimpi.modbus.Modbus;
import net.wimpi.modbus.io.ModbusTCPTransaction;
import net.wimpi.modbus.io.ModbusTransaction;
import net.wimpi.modbus.msg.ModbusRequest;
import net.wimpi.modbus.msg.ReadInputRegistersRequest;
import net.wimpi.modbus.msg.ReadInputRegistersResponse;
import net.wimpi.modbus.msg.WriteSingleRegisterRequest;
import net.wimpi.modbus.net.TCPMasterConnection;
import net.wimpi.modbus.procimg.SimpleRegister;

/**
 * Class that implements a simple commandline
 * tool which demonstrates how a analog input
 * can be bound with a analog output.
 * <p/>
 * Note that if you write to a remote I/O with
 * a Modbus protocol stack, it will most likely
 * expect that the communication is <i>kept alive</i>
 * after the first write message.<br>
 * This can be achieved either by sending any kind of
 * message, or by repeating the write message within a
 * given period of time.<br>
 * If the time period is exceeded, then the device might
 * react by turning pos all signals of the I/O modules.
 * After this timeout, the device might require a
 * reset message.
 *
 * @author Dieter Wimberger
 * @version @version@ (@date@)
 */
public class AIAOTest {

    public static void main(String[] args) {

        InetAddress addr = null;
        TCPMasterConnection con = null;
        ModbusRequest ai_req = null;
        WriteSingleRegisterRequest ao_req = null;

        ModbusTransaction ai_trans = null;
        ModbusTransaction ao_trans = null;

        int ai_ref = 0;
        int ao_ref = 0;
        int port = Modbus.DEFAULT_PORT;

        try {

            // 1. Setup the parameters
            if (args.length < 3) {
                printUsage();
                System.exit(1);
            } else {
                try {
                    String astr = args[0];
                    int idx = astr.indexOf(':');
                    if (idx > 0) {
                        port = Integer.parseInt(astr.substring(idx + 1));
                        astr = astr.substring(0, idx);
                    }
                    addr = InetAddress.getByName(astr);
                    ai_ref = Integer.parseInt(args[1]);
                    ao_ref = Integer.parseInt(args[2]);

                } catch (Exception ex) {
                    ex.printStackTrace();
                    printUsage();
                    System.exit(1);
                }
            }

            // 2. Open the connection
            con = new TCPMasterConnection(addr);
            con.setPort(port);
            con.connect();
            if (Modbus.debug) {
                System.out.println("Connected to " + addr.toString() + ":" + con.getPort());
            }

            // 3. Prepare the requests
            ai_req = new ReadInputRegistersRequest(ai_ref, 1);
            ao_req = new WriteSingleRegisterRequest();
            ao_req.setReference(ao_ref);

            ai_req.setUnitID(0);
            ao_req.setUnitID(0);

            // 4. Prepare the transactions
            ai_trans = new ModbusTCPTransaction(con);
            ai_trans.setRequest(ai_req);
            ao_trans = new ModbusTCPTransaction(con);
            ao_trans.setRequest(ao_req);

            // 5. Prepare holders to update only on change
            SimpleRegister new_out = new SimpleRegister(0);
            ao_req.setRegister(new_out);
            int last_out = Integer.MIN_VALUE;

            // 5. Execute the transaction repeatedly
            do {
                ai_trans.execute();
                int new_in = ((ReadInputRegistersResponse) ai_trans.getResponse()).getRegister(0).getValue();

                // write only if differ
                if (new_in != last_out) {
                    new_out.setValue(new_in); // update register
                    ao_trans.execute();
                    last_out = new_in;
                    if (Modbus.debug) {
                        System.out.println("Updated Register with value from Input Register.");
                    }
                }
            } while (true);

        } catch (Exception ex) {
            ex.printStackTrace();
        } finally {
            // 6. Close the connection
            con.close();
        }
    }// main

    private static void printUsage() {
        System.out.println(
                "java net.wimpi.modbus.cmd.AIAOTest <address{:<port>} [String]> <register a_in [int16]> <register a_out [int16]>");
    }// printUsage

}// class AIAOTest