Use logic to set SRM Clock

[CTSoft 0]

Send_Message_to_SRM.doc Hi to all, Presently, I'm working on Controllogix Redundant System. The chassis is 4 slot chassis, on slot 0: 1756-L61, slot 1: 1756-CNBR slot 2~3 : 1757-SRM. I want the SRM clock synchronize with the controllogix processor date and time. But I'm not able to make it work. Anyone can advise, where i make the mistake? Attached screen shot for reference.Thanks. Best Regards, CT

[Contr_Conn 4]

What redundancy version you have? In V16 attribute number changed due to new clock format. It is now attribute 11 (0B-hex) See TN 54971 Edited 2 Dec 2008 by Contr_Conn

[CTSoft 0]

Contr_conn, Thanks for your help. The date in the SRM is updated now , but for the current time it's 8 hours different. Look like this is due to the time zone GMT +0800. Is there anyway to work around it?

[Contr_Conn 4]

I am not sure what value you are writing to it - your V16 controller uses GMT, and SRM attribute 11 is with local offset. You can try attribute 6 (UTC time), but I never tested it and can't say if it works

[Contr_Conn 4]

Ok, here is what I got so far: Attribute 6 is not implemented in SRM. When you read CST from controller (GSV) it comes as GMT value When you write it to SRM (attribute 11) SRM will be set as GMT So both devices will be using same CST Problem is that SRM does not have Time Zone offset implemented If you read time from controller properties online it will display time as Local Time, applying time zone offset found in PLC. If you read SRM properties it will display GMT (no time zone offset in SRM). Also it looks like SRM configuration tool does not apply workstation Time zone to display correct time. It looks like you can add time zone offset before sending message to attribute 11, but luck of 64 bit math makes these calculations complicated. I will try to get more information about this later on. Edited 3 Dec 2008 by Contr_Conn

[CTSoft 0]

Thanks for the information, It seen to be worked now. Refer to attached screen shot on offline (forgot capture when online), I set the date and time by using change date and time button, instead of using date,time and zone workstation button. workstation button to set the date and time.

[paulengr 44]

Can't you just use getlocaltime (or the equivalent) on the CLX and set SRM time based on this? Then the CLX does the conversion for you.

[Contr_Conn 4]

CLX does not have "get local time" as 64 bit value, it has only GMT as 64 bit valueLocalTime available in PLC as DINT[7], but not implemented in SRM. To build 64bit local time from GMT you will need 64bit multiplication that is not available in CLX yet. Technically you need this only if you want to set time programmatically. RSlinx GUI sets it to workstation time correctly.

[CTSoft 0]

Thanks for the hint and information, gentlemens. I have some issues that I need your advise again. How can i use program logic to initiate the switchover when primary processor is switched to program mode? I had read through the user manual 1756-UM523F, it only guided me how to configure a message to initiate switchover. Any suggestions?

[Contr_Conn 4]

To finish our SRM Clock conversation - see TN 57158 - this is exactly what you want to do. If you switch primary to program mode then secondary will go to program mode also - this is done by design. Secondary always follow the primary. You will have to initate switchover first and after that you can put secondary (former primary) to the program mode. Edited 10 Dec 2008 by Contr_Conn

[CTSoft 0]

Is there anyway we can detect the transition happen when primary processor going to switch from RUN to Program mode?