Ethernet Communications to Compact Logix

Hi All,

i am trying to get a backup of several machines at the plant over ethernet. each machine has several ethernet devices and a individual ethernet switch. the machines are not connected together.

i looked at the plc program and found the ip address and set my laptop to the main numbers but with a different last number. submask of 255.255.255.0.

trouble is, my rslinx pro does not see the plc.
i also cannot get onto the plc with logix 5000 via ethernet.

I CAN connect via serial port and download the program and did confirm the ip address. its the same as the one i had.
i just used my ethernet cable 5 minutes before and have had it tested and have confirmed its ok.

I am trying to learn the logix 5000 software and have been able to connect to other plc's in the past.

All comments welcome!
thanks in advance,
james

Open a command prompt and try to ping the plc IP address or the address of some of the other devices to make sure you have a connection.

Are you connecting to a switch? The switch may have MAC address filtering meaning the switch will not pass traffic from your laptop if the MAC ID number of your network card is not in the list in the switch.

What linx driver are you using? The ethernet IP driver or the ethernet devices driver. The ethernet devices driver you must type in the addresses of the device you want to comm with.

If linx does not see the plc then logix will never connect as it connects through linx. Concentrate on getting ping working because it is the lowet level comms you have in your aresenal.

If you can't ping the plc then noting else is going to work.

If you have windows firewall or antivirus on that laptop turn it off as it can impede traffic. The windows firewall is known for this.

You can setup exceptions once it is working but turn them off until you get things running.

Also what OS are you running?

Thanks for the suggestion of ping.

I'm running Windows XP pro SP2.
running latest version of linx.

regards,
james

What type RSLinx driver are you using?
An EtherNet/IP driver configured for a PC network card having the same first three "numbers" of the IP Address of the bridge managing the subnet the PC is patched into will return (when browsing)the icons of all the subnet's active/connected devices.
An EtherNet driver used within the same scenario as the one previously described, will return only the addresses entered at the driver's configuration time.
I would first make sure you are using an EtherNet/IP type driver when trying to connect to the subnet.

did you confirm you PLC's subnet mask to be 255.255.255.0

i am using ether net not the ip driver.
I retyped in the addresses of the ethernet device with no success.
I then changes the ip address of my laptop from x.x.x.235 with submask of 255.255.255.0 to x.x.x.186 and it worked.

only two ethernet devices on this machine.
why would changing the address from 235 to 186 matter?

regards,
james

Could have been a device that would not appear in RSlinx with the same address.

With that subnet anything from 1 to 254 that is not taken should be fair game. An ip conflict should have thrown an error, try pinging 235 now to see if you get a response.