Test the connection to the PLC

Check whether the communication with the control device (PLC) can be established.

Before you can test the connection, you must enable the COM interface on the COM Interface page (e.g. to test RS232, enable COM1 RS232) and configure a redirect to a TCP port (see "Related topics").

You can only test MEWTOCOL and MEWTOCOL7 connections (Modbus connections cannot be tested).

Open the Port page and go to the Test connection to PLC section.
Select the desired button.
If the button is disabled, make sure the COM interface is enabled and a port has been opened.
- Test RS232: Test the connection between COM1 RS232 of the FP-I4C unit and the control device (PLC).
- Test RS485: Test the connection between COM2 RS232/RS485 of the FP-I4C unit and the control device (PLC).
  
  Depending on the Mode setting on the COM Interface page, COM2 can be an RS232 or RS485 interface.
- Test USB: Test the connection between COM3 USB of the FP-I4C unit and the control device (PLC).
  
  The FP-I4C unit has two USB slots, but you can connect only one PLC to the USB interface. We recommend to use the bottom slot, because the top slot provides a current of 500mA that may be useful for other devices.
- Test Ethernet: Test the connection between the FP-I4C unit and the interface settings made on the COM Interface page for COM4 Ethernet.

Possible results when testing a connection:

Successful– If the connection test was successful, the connected PLC type and the response time in milliseconds is displayed.
Timeout – If this error occurs, check the following:
- Is the cable to the PLC plugged in?
- Is the wiring correct?
- Is the power supply of the PLC on?
- Are the same communication parameters set for the PLC and for the FP-I4C unit?
Failed - connect ECONNREFUSED – If this error occurs, check the following:
- Has the maximum number of clients been exceeded?
- Is the COM interface used more than once? (You must use different COM interfaces for configuration and for HMWIN Studio.)
- Did you test the connection immediately after saving your settings? Wait for about 10s before you make the connection test.