Our system is currently using a 1500 cpu and an IM ET200SP. they communicate via ethernet cable with approximate length of 80m.

Communication between works perfectly fine but everytime that a powerfailure occur and after getting back to normal power state, the PLC can no longer detect the IM. I have to disconnect and reconnect the ethernet connector a few times to get it back online.

On PLC side, the ethernet LED diagnistics flickers green-yellow-LED Off. I can't find the definition of this particular LED sequence in the 1500 Manual.

Hello keyots

Typically there are 2 LEDs on every LAN Interface.  The Functions of the LEDs are on almost every LAN Interface the same. (I Do not know if the LAN LEDs on the PLCs have special functions )

On some Systems the LINK LED can also be yellow if the native Speed (for example 1GBit/s) is not possible and when there is a link to a slower device like 10MBit/s

Bye Murof

The ethernet LED on the 1500 is different. It has only one LED per port. It lights yellow when it has stable connection with IM.

Anyway, i'm sure the LED sequence indicates that my PLC can't connect to IM. Could you give me idea what could cause the inconsistent connection?

Hello Keyots

I´m sorry here you can see the Meaning of the specialised LEDs of S71500

Bye Murof

keyots,

On both your 1500 and ET200SP go to the ports Advanced options and check that the transmission rate is set to automatic.

You can play with setting it to a specific speed, but make sure that they are set identical on both sides.

we have resolve the network error by placing an Ethernet switch with the IM. It seems that there is a signal loss using the particular ethernet cable we have when connecting any device to an IM.

Thanks to all who sent their ideas. appreciate it alot.