Synchronization betweenRockwell PLCs.

Hello everyone and thank you for your answers.

I write because in my project I have to solve synchronization problems between Rockwell PLCs.

In my case I have a PLC with a HP-TIME module that acts as a master and other slave PLC (connected via Ethernet) and some power monitor (connected via ControlNet).

I was wondering if there is a way to make a SSV directly from the master to the slave; or, in other hand, if there is a ladder command to set the slave's system varibile WALLCLOCKTIME, from the master.

Thanks

What CPU types are we "talking" about; Model # and Firmware Revision?

peterpan405 said:

Hello everyone and thank you for your answers.

I write because in my project I have to solve synchronization problems between Rockwell PLCs.

In my case I have a PLC with a HP-TIME module that acts as a master and other slave PLC (connected via Ethernet) and some power monitor (connected via ControlNet).

I was wondering if there is a way to make a SSV directly from the master to the slave; or, in other hand, if there is a ladder command to set the slave's system varibile WALLCLOCKTIME, from the master.

Thanks

Click to expand...

Since you mentioned SSV I assume you are using Logix5000 controllers (eg. ControlLogix, CompactLogix, DriveLogix etc.).

Probably your best option is to GSV the date/time from the WallClock in the "Master" controller, into a tag that you can Produce for other controllers to Consume. There is probably no need to actually set the clock in the "slaves", just use the consumed data from the consumed tag as if it had been GSV'd from the slaves wallclock.

Because you have a time server module, you (or somebody else) probably designed your control system to have specific time synchronization features.

The 1756HP-TIME module is specifically built to be the "grandmaster clock" in a ControlLogix system that synchronizes multiple controller clocks. It's more complicated and more accurate than using GSV and SSV and Produced/Consumed Tags.

Start with the documentation for your 1756HP-TIME module and find out if the ControlLogix and the Ethernet modules in your system are appropriate for use with a PTP network.

I'm not an expert using these modules, but I'm sure the PLCTalk Forum community can help you with specific questions.

http://www.hiprom.com/Pages/Products/1756_CLX/1756HP-TIME/web/1756HP-TIME.htm

Thanks Ken - I wasn't aware that the HP_TIME module was a 1756 module, obviously a "special" and would need an appropriate Add-On Profile to be available in the I/O configuration dialogs.

Wow! that module looks like the bees-knees !!