Control logix Plc Time Sync

Hi All,

How can I configure the PLC to be a "Synchronized Time Slave" ?

When I enable Time sync, it sets the PLC as the master by default. Didn't find any other option in the menu.
Or am I missing some information here?

Thanks for the help.

Shrey said:

Hi All,

How can I configure the PLC to be a "Synchronized Time Slave" ?

When I enable Time sync, it sets the PLC as the master by default. Didn't find any other option in the menu.
Or am I missing some information here?

Thanks for the help.

Click to expand...

What do you want to sync it with? Is there another PLC in the network? Are you trying to set up a network based time sync?

Need to know those things to get up to speed here.

Click Adv - lower its priority

PreLC said:

What do you want to sync it with? Is there another PLC in the network? Are you trying to set up a network based time sync?

Need to know those things to get up to speed here.

Click to expand...

I have configured a NTP Server on one of the computers on the network. I wish to point the plc to that computer for the timing.

use socket to read time from the NTP server,

Shrey said:

I have configured a NTP Server on one of the computers on the network. I wish to point the plc to that computer for the timing.

Click to expand...

Surprise! You can't.

Contrologix can "see" other PTP sources but are absolutely blind to NTP so it's not going to sync to the PC... unless..

you run the clock-sync tool from Rockwell to set the time on the PLC. Which doesn't involve NTP at all.

or

You can buy a 1756-TIME card that can translate NTP to PTP and send it to the PLC on the backplane.

!! However, once you have one PLC on the network that is sync somehow to a PC. That PLC can act as PTP master to other PLC on the network.

Like I said, you can with socket.

What is a socket and how to use it? Actually, I am new to the world of plcs.

I will tell you exactly what I want to do.

We are using the controllogix plc and Wonderware System Platform 2017 SCADA. I am displaying the plc time on SCADA. And also if there is any lag between the PLC time (Displayed on SCADA) and the SCADA computer time, SCADA mimic page will have a button to sync the time.
SCADA computer is part of a network that has got NTP Server. The client has provided IP address of that computer. So I wish to point the plc to that NTP server hosting computer or the SCADA computer.

I used the clock sync tool from Rockwell. But I believe that will work only if the studio 5000 is open on the computer (That will not be the case all the time).

So I there a way that I can point the PLC to any other source? (Without putting a dedicated module with the plc)

Thank you very much for explaining your purpose.

ControlLogix is a little unusual among industrial controllers because it uses precision time synchronization for motion control and safety purposes, as well as deriving its ordinary time and date from that clock.

This makes it a little difficult to adjust the "Wall Clock" time frequently without disrupting the precision time features, and is one of the reasons Rockwell has long resisted adding an NTP Client to the ordinary Ethernet modules.

If your application is just trying to keep the SCADA system and the ControlLogix within a couple seconds of one another, then you can use the ordinary Logix 5000 Clock Update Tool. It doesn't need Studio 5000 to be running, nor a licensed version of RSLinx Classic (just Lite) and is appropriate for installation on a computer that also gets its time via NTP from a time server like the ordinary NIST time servers that run off the US Navy's atomic clocks.

You can get the current version of the Logix 5000 Clock Update Tool from Rockwell, in Knowledgebase Document #44321 (Access Level: Everyone).

If you're up for the latest and greatest method, there's a newer Logix 5000 Clock Sync Service you can try. It was released in conjunction with Studio 5000 v24, and there is an overview document on the RA Knowledgebase, Document #641235 (Access Level: Everyone).

Ken Roach said:

You can get the current version of the Logix 5000 Clock Update Tool from Rockwell, in Knowledgebase Document #44321 (Access Level: Everyone).

If you're up for the latest and greatest method, there's a newer Logix 5000 Clock Sync Service you can try. It was released in conjunction with Studio 5000 v24, and there is an overview document on the RA Knowledgebase, Document #641235 (Access Level: Everyone).

Click to expand...

I will add that another difference between these methods is that the Clock Update Tool needs to run in a logged-in user session on a networked PC, whereas the Clock Sync Service can run on a networked server with no persistent login.

I'd suggest to go with Ken's suggestion, since socket require a bit of know-how.
Clock sync is installed as a service, but Clock Update tool can be made to run as a service.

Thanks guys for the help!

I installed the new Clock update tool on my SCADA computer, configured the tool as shown in the image below and made the SCADA computer to point to a particular NTP Server.

To test the setup, I changed the time on the plc (Studio 5000 running on a different VM).

I am assuming that ideally when you configure like this, the plc would take the time from the SCADA computer as we have set on the clock update tool. But the Clock update tool is showing " Not Synchronized". So did I miss something while doing the setup?

Set the priority of the server to be a lower number (higher priority) than that of the PLC. Change it at either end.

Geoff White said:

Set the priority of the server to be a lower number (higher priority) than that of the PLC. Change it at either end.

Click to expand...

Thanks to your advice Geoff, I could go one step further! I put a lower priority on the plc clock (higher number) and configured higher priority on the clock sync tool running on the SCADA computer.

But now in the Advanced Time Sync dialogue box, I can see that the Grandmaster clock keeps on fluctuating between the plc itself and the SCADA computer every sec. I have also configured the correct Tie breaker priority at both places.

What could be the reason for that?

Just to provide you more info- Studio 5000 & the SCADA they are running on the same computer on different VMs. I have set the connection for VMs as bridged so that each VM can get its own IP.

Also, One thing that I observed is- If the plc time is completely different from that actual time and the plc is sync with the SCADA computer (plc being the Slave), Plc doesn't correct its time even when it is displaying SCADA as the grandmaster. So whole purpose of configuring the master-slave combo gets defeated.
On the other hand, while using a logix5000 clock update tool plc does correct its time as per the schedule.

One thing to check is that the PLC and the VMs are all using the same timezone. CST is based on UTC.