Ping Command in CompactLogix/ControlLogix PLC - PLCS.net

mahone · November 13th, 2017, 02:05 AM

hi all,

how to implement Ping command in CompactLogix PLC so that i can
check the com link between the plc and a computer it's connected to?

thanks

willxfmr · November 13th, 2017, 05:49 AM

I may well be mistaken, but I believe the ping command will have to come from the PC to the PLC, not the other way around.

Bubba.

jstolaruk · November 13th, 2017, 08:30 AM

Look into the many options available in the GSV command, you may find something.

mk42 · November 13th, 2017, 09:42 AM

I'm not aware of any PLC that has a Ping command native.

My understanding is that you can send TCP or UDP packets with the MSG command. These allow you to implement most protocols, but you would pretty much need to be able to send raw Ethernet (layer 2) packets to be able to do Ping or other ICMP commands.

harryting · November 13th, 2017, 11:33 AM

Most PLC doesn't do ping. What you can do is a watchdog or heartbeat.

Depending on where you want the alarm to be fired off you would have the other side send a changing sequence and check for for that variation. If it stops, fire off the alarm.

Ken Roach · November 13th, 2017, 11:43 AM

You almost certainly don't want a PING command. PING doesn't tell you anything about the status or type of device on the network.

You probably want a watchdog function. I usually do this by having the HMI computer write the /Seconds value from the PC clock to the PLC. As long as the tag it is writing to is changing, I know that the PC is connected and that the HMI program is executing.

Another method I have used with PanelView and computers running RSLinx is to send a MSG instruction with the CIP object to read part of the Identity Object. When you get a reply to such a message, you know that the computer is connected and that RSLinx is running.

GeneralJim · July 19th, 2020, 02:41 AM

Quote:

Originally Posted by Ken Roach

You almost certainly don't want a PING command. PING doesn't tell you anything about the status or type of device on the network.

You probably want a watchdog function. I usually do this by having the HMI computer write the /Seconds value from the PC clock to the PLC. As long as the tag it is writing to is changing, I know that the PC is connected and that the HMI program is executing.

Another method I have used with PanelView and computers running RSLinx is to send a MSG instruction with the CIP object to read part of the Identity Object. When you get a reply to such a message, you know that the computer is connected and that RSLinx is running.

I want to check if FTLinx is running on a PC. @Ken Is this possible using the method mentioned. If so, can you give some more details on reading the identity object please?

Dayvieboy · July 19th, 2020, 03:07 AM

We build watch dog heart beats into most of our SCADA systems.
Every 250 ms we increment a tag in the PLC from the SCADA system.
.
This gives you dynamic live data about the system connection, unlike a ping that is only a low level check.
.
We do this in:
Wonderware, Ignition, Citect, RsView, Win CC, LabView

Dayvieboy · July 19th, 2020, 03:07 AM

We build watch dog heart beats into most of our SCADA systems.
Every 250 ms we increment a tag in the PLC from the SCADA system.
.
This gives you dynamic live data about the system connection, unlike a ping that is only a low level check.
.
We do this in:
Wonderware, Ignition, Citect, RsView, Win CC, LabView

mike_dr · July 19th, 2020, 12:32 PM

you need to check in the pc with ftlinx. its impossible to do it in plc

cardosocea · July 19th, 2020, 12:48 PM

Quote:

Originally Posted by GeneralJim

I want to check if FTLinx is running on a PC.

Ping will merely tell you that the IP address you pinged is connected to the network. It may even be another PLC, IO, HMI, Server, you name it... but it won't be Linx.

GeneralJim · July 19th, 2020, 01:19 PM

Quote:

Originally Posted by cardosocea

Ping will merely tell you that the IP address you pinged is connected to the network. It may even be another PLC, IO, HMI, Server, you name it... but it won't be Linx.

I am aware of this. The only reason I replied in this thread was because I wanted more information on Ken’s post regarding the identity object.

mad4x4 · July 20th, 2020, 01:12 PM

You should be able to read a packet of data and write a packet of data to and from the device using GSV commands but not the simplest and may take a bit of time with wire shark, best way is to re/write a Tag to/from Scada and verify as a watchdog.

Mmaybe a better question to ask is why do you need to know the machine is alive or dead? Does the PLC need to know the PC is present?

Dayvieboy · January 19th, 2023, 10:55 PM

Mmaybe a better question to ask is why do you need to know the machine is alive or dead? Does the PLC need to know the PC is present?[/QUOTE]

Sometimes the PC collects data from other sources the PLC uses for interlocks, if the PC stops communicating we shut down some devices.

TheWaterboy · January 20th, 2023, 02:42 PM

I would imagine it might be possible to construct one with open sockets wouldn't it? Not that I would know how, but I thought Open Sockets opened all possibilities...

November 13th, 2017, 02:05 AM	#1
mahone Member Join Date: Apr 2014 Location: Singapore Posts: 62	Ping Command in CompactLogix/ControlLogix PLC hi all, how to implement Ping command in CompactLogix PLC so that i can check the com link between the plc and a computer it's connected to? thanks

November 13th, 2017, 05:49 AM	#2
willxfmr Lifetime Supporting Member Join Date: Nov 2013 Location: Wisconsin Posts: 460	I may well be mistaken, but I believe the ping command will have to come from the PC to the PLC, not the other way around. Bubba. __________________ “Now will come the nay-sayers with all the reasons why you shouldn't do this. Some of them are teachers, and some of us are doers. Besides, you have got to let the smoke out of this equipment every now and then, or it starts to clog up the chimney.” ~Lancie1

November 13th, 2017, 08:30 AM	#3
jstolaruk Lifetime Supporting Member Join Date: Dec 2004 Location: Detroit, SE Michigan Posts: 3,796	Look into the many options available in the GSV command, you may find something. __________________ I don't always test my code but when I do, I do it in production.

January 20th, 2023, 02:42 PM	#15
TheWaterboy Lifetime Supporting Member + Moderator Join Date: May 2006 Location: State of Denial Posts: 1,538	I would imagine it might be possible to construct one with open sockets wouldn't it? Not that I would know how, but I thought Open Sockets opened all possibilities... __________________ . . .Nostalgia used to be so much better . . .

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November 13th, 2017, 09:42 AM	#4
mk42 Lifetime Supporting Member Join Date: Jun 2013 Location: MI Posts: 2,900	I'm not aware of any PLC that has a Ping command native. My understanding is that you can send TCP or UDP packets with the MSG command. These allow you to implement most protocols, but you would pretty much need to be able to send raw Ethernet (layer 2) packets to be able to do Ping or other ICMP commands.

November 13th, 2017, 11:33 AM	#5
harryting Lifetime Supporting Member Join Date: May 2002 Location: Puget Sound Posts: 2,530	Most PLC doesn't do ping. What you can do is a watchdog or heartbeat. Depending on where you want the alarm to be fired off you would have the other side send a changing sequence and check for for that variation. If it stops, fire off the alarm.

November 13th, 2017, 11:43 AM	#6
Ken Roach Lifetime Supporting Member + Moderator Join Date: Apr 2002 Location: Seattle, WA Posts: 16,856	You almost certainly don't want a PING command. PING doesn't tell you anything about the status or type of device on the network. You probably want a watchdog function. I usually do this by having the HMI computer write the /Seconds value from the PC clock to the PLC. As long as the tag it is writing to is changing, I know that the PC is connected and that the HMI program is executing. Another method I have used with PanelView and computers running RSLinx is to send a MSG instruction with the CIP object to read part of the Identity Object. When you get a reply to such a message, you know that the computer is connected and that RSLinx is running.

July 19th, 2020, 03:07 AM	#8
Dayvieboy Lifetime Supporting Member Join Date: Jun 2013 Location: San Francisco Bay Area Posts: 114	We build watch dog heart beats into most of our SCADA systems. Every 250 ms we increment a tag in the PLC from the SCADA system. . This gives you dynamic live data about the system connection, unlike a ping that is only a low level check. . We do this in: Wonderware, Ignition, Citect, RsView, Win CC, LabView

July 19th, 2020, 12:32 PM	#10
mike_dr Member Join Date: Oct 2011 Location: Mla Posts: 215	you need to check in the pc with ftlinx. its impossible to do it in plc

July 20th, 2020, 01:12 PM	#13
mad4x4 Member Join Date: Mar 2009 Location: ST CYrus Posts: 288	You should be able to read a packet of data and write a packet of data to and from the device using GSV commands but not the simplest and may take a bit of time with wire shark, best way is to re/write a Tag to/from Scada and verify as a watchdog. Mmaybe a better question to ask is why do you need to know the machine is alive or dead? Does the PLC need to know the PC is present?

January 19th, 2023, 10:55 PM	#14
Dayvieboy Lifetime Supporting Member Join Date: Jun 2013 Location: San Francisco Bay Area Posts: 114	Mmaybe a better question to ask is why do you need to know the machine is alive or dead? Does the PLC need to know the PC is present?[/QUOTE] Sometimes the PC collects data from other sources the PLC uses for interlocks, if the PC stops communicating we shut down some devices.

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