I can communicate to the plc but can't ping it

I am able to establish communication through rslinx but I can't ping the PLC or any field devices why is that?

Welcome, well you haven't really provided enough information.

What PLC?

One possibility is there is a router/firewall in the mix that is blocking ICMP ping but allowing the port for AB comms through.

At the end of the day, I wouldn't care. If you have comms, you have comms. Unless you are running SCADA to periodically ping your device for connection status, then program it and move on.

I am trying to use pylogix to read tag values but I always get a None reply according to other forums it's because I can't ping the device, so that is why I am trying to ping.

I can communicate to all of the plcs remotely through rslinx but can't ping to any of them unless I connect directly to the switches inside the cabinets and change my subnet.

One possibility is there is a router/firewall in the mix that is blocking ICMP ping but allowing the port for AB comms through.

Click to expand...

/Switch

Check your default gateways and subnet masks if you are traversing subnets.

FEGF said:

I am trying to use pylogix to read tag values but I always get a None reply according to other forums it's because I can't ping the device, so that is why I am trying to ping.

Click to expand...

What does it say when you print the status of the response? Also, what PLC model is it?

Browsing through the backplane from one subnet to another?

AttributeError: 'Response' object has no attribute 'Return'

sorry typo I get "Path destination unknown"

What is your network architecture like? Can you share a network diagram?

Path destination unknown is the PLC telling you the tag doesn't exist. So pylogix is connecting to your PLC. You either have a typo in the tag name, it is program scoped and you are not using the program scope syntax, or its external access is set to None.

Can you post your code?

got it to work man I got a typo in the tag name

FEGF said:

got it to work man I got a typo in the tag name

Click to expand...

Nice. You came to the right place, so if you need any pointers, let me/us know.

Pylogix and Micro 820 PLC communication

dmroeder said:

Nice. You came to the right place, so if you need any pointers, let me/us know.

Click to expand...

Hi all,

First of all thanks to dmroeder for sharing links to PYLOGIX for everyone to use. It's a handy tool to have as an automation engineer.

I'm using a Micro 820 PLC and a PanelView 800 HMI on a site to control a small skid. I've set up the HMI to log 3 x Analog values and 1 x Digital value on a USB drive plugged into the PanelView 800 HMI but the records always have some corrupted data in a few rows and logs data normally again.

I've turned to PYLOGIX as a solution and I tried a demo using a Micro820 PLC in our office. I've changed the IP address of the PLC and I've set the Ethernet port slot number of the Micro820, in the Pylogix code, as 2 and added a Digital Tag to start with. However the GUI, of Pylogix, always shows "NOT CONNECTED" on the Left hand bottom of Pylogix's GUI. I can ping the PLC from my computer as always. There're no switches etc. in between. I even tried reading tags by clicking the GET TAGS button on the GUI but it displays "No Tags retrieved".
I tried changing the slot number to 4, for the Micro820, and disabled other network drivers on my computer but no luck yet.
I also tried adding the following lines in Pylogix:

from pylogix import PLC

tags = ['tag']
with PLC () as comm:
comm.IPAddress = 'IPADDRESS'
ret = comm.Read('TAG')
print(ret.Value)

I haven't managed to get it to work yet. Any suggestions would be really helpful. Sorry for the lengthy post.
Thanks..

Anthony PLC said:

Code:

  from pylogix import PLC

tags = ['tag']
with PLC () as  comm:
    comm.IPAddress = 'IPADDRESS'

    comm.Micro800 = True          ### Add this

    ret = comm.Read('TAG')
    print(ret.Value)

Click to expand...

Pylogix connections to Micro8xx need the .Micro800 member assigned a value of True; see the Add this line above, that may fix it.