Read and write I/O

This article shows how to read and write the inputs and outputs of a Yaskawa Motoman controller from a PC, in C# or Python. It gives a complete program that sets a network input, waits for a general output, then clears the input.

Prerequisites

• The SDK is connected to the controller: see Connect to your robot.
• The job or the ladder of the controller uses the network inputs that the PC writes.

Three calls

The PC writes only the network inputs. To act on the cell, the job or the ladder of the controller reads them and switches its outputs.

Example

using UnderAutomation.Yaskawa;
using UnderAutomation.Yaskawa.HighSpeedEServer;
using UnderAutomation.Yaskawa.Common;

public class HowToReadWriteIo
{
    static void Main()
    {
        
        var robot = new YaskawaRobot();
        robot.Connect("192.168.0.1");

        // 1. Signal #27013: bit 3 of group 1 of the network inputs
        const ushort group = 1;
        const int bit = 3;

        // 2. Set the bit, keep the other bits of the group
        byte current = robot.HighSpeedEServer.ReadIO(IOType.NetworkInput, group, 2).Value[0];
        byte next = (byte)(current | (1 << bit));
        robot.HighSpeedEServer.WriteIoNetworkInput(group, new byte[] { next, 0 });

        // 3. Wait for the general output #10010 (bit 0 of group 1), at most 10 seconds
        DateTime timeout = DateTime.Now.AddSeconds(10);
        while ((robot.HighSpeedEServer.ReadIO(IOType.GeneralOutput, 1, 2).Value[0] & 1) == 0)
        {
            if (DateTime.Now > timeout) throw new TimeoutException("#10010 stayed off");
            Thread.Sleep(50);
        }

        // 4. Clear the network input
        robot.HighSpeedEServer.WriteIoNetworkInput(group, new byte[] { (byte)(next & ~(1 << bit)), 0 });

        robot.Disconnect();
        
    }
}

The program:

1. takes the signal #27013: bit 3 of the group 1 of the network inputs;
2. reads the group, sets the bit and writes the group back, so that the other bits keep their state;
3. reads the general output #10010 every 50 ms until it is on, with a timeout of 10 s;
4. clears the bit.

Signal numbers

A signal number has 5 digits: the group, then the bit. The group of a type starts at a fixed number: 1 for the general inputs, 1001 for the general outputs, 2701 for the network inputs. The table of every type is in Inputs and outputs.

Troubleshooting

• The write is refused: the PC can write only the network inputs. Use a network input and let the ladder copy it to an output.
• The write needs an even number of values: write two groups. Read them first so that the second group keeps its state.
• The bit does not change on the pendant: check that you test the right bit. The bit 0 is the signal ending with 0.

What to read next

• Inputs and outputs: the I/O types and the reference.
• Monitor the state of the robot.