Solution:

To find out why your driver is transmitting but not receiving messages 1. Examine the cable. 2. Verify that communication parameters for the hardware match the parameters configured in the driver. NOTE: You can usually check the communication ports and the cable by using the programming software with the same cable on the machine. If this works, usually the cable is okay. 3. If the driver is a TCP/IP-based driver, you should attempt to ping the IP address. This action verifies that your computer can communicate with the device. 4. Examine your process hardware. See if any diagnostic lights on the device indicate what the problem is. At this point, we strongly recommend reducing the configuration to one channel, one device, and one datablock. This makes it easier to focus on the problem. To reduce the configuration to one channel, one device, and one datablock 1. Disable all but one channel. 2. On the one enabled channel, disable all but one device. 3. On the one enabled device, disable all but one datablock. 4. Verify that the device's station address is correct. Usually, the wrong station address returns an error message; however, some hardware devices do not reply at all if you enter the wrong station address.