help needed in TON counter preset value

Hi pal,
Need some enlightentment about the timer counter's preset value.
The preset value changes to the default value whenever i am in the online mode. Appreciate if anyone could share some pointer to resolve on this minor glitch.

Thanks!

Timer

You have some other call moving a 7 into your preset. If not in your program, then across the network, possibly another SLC or maybe a PanelView or a SCADA system.

Till you find out the problem, you could move your MOV block rung right before your counter rung. This would insure the 1 being moved to the preset.

I had this happen to me on an ML1000. every Monday morning the department that this machine was in wanted the timer changed because they said it went back to the "default" value. Nobody had access to the laptop to change it to anything other than the preset it was supposed to be and I even hid the handheld programmer in the event that someone wa getting it on the weekends and messing with it. There was no HMI on this machine and it was not networked in any way. I eventually added a rung to MOV the preset I wanted on the first scan and I never again had a problem.

is there any reason why you can't zip your .RSS program file and post it?

Re: Timer

Mark Buskell said:

You have some other call moving a 7 into your preset. If not in your program, then across the network, possibly another SLC or maybe a PanelView or a SCADA system.

Till you find out the problem, you could move your MOV block rung right before your counter rung. This would insure the 1 being moved to the preset.

Click to expand...

Hi Mark,
Thanks for a good pointer. Apparently, my system is being"networked" with few RIOs. No SCADA system and and other SLC associated with it. Will go and verify again if there are hidden link which i am not aware of.

At the mean time, I am thinking to shift the "MOV" command way before the counter as what you high lighted also. However I am in doube what would be the consequences to the whole program. If there is no cross reference link able to be found under that particular MOV command, does it means i am safe to move it else where as i like?

Thanks for your kind feedback again.

CS

Ron Beaufort said:

is there any reason why you can't zip your .RSS program file and post it?

Click to expand...

Hi Ron,
Am thankful for your kind reminder.
Perhaps I am not so familiar with the steps to transform the logic display into what you had suggested.

Any steps to guide me along?

Many thanks!

CS

first use something like Winzip to zip the file up ...

then take a look

here

post again if you need more help ...

Assuming that you have searched for any other MOV or math instructions involving T4:171.PRE, and that the other reccomendations mentioned above don't pan out...

There is also a possibility that the rung that includes the MOV is in a LAD file or a section that is not being scanned by the processor.

Is that rung in the same LAD file as TON?

Is there a JSR for that file (or is it in LAD2)?

If the file is being scanned, is there any JMP<>LBL or MCR instructions in that file?



It would be helpful if you post the .RSS file.

Hi there,
My timer was at the subroutine file 11 whilst my mov command was located at the subroutine file 16. For each of the first rung scan, there are the SBR command.

Hope that able to give you some more info in resolving my problem.

Thanks.

csloh said:

For each of the first rung scan, there are the SBR command.

Click to expand...

That's fine, but it still doesn't mean that file #16 is actually being scanned. Look for a JSR 16, see if it is conditional, etc.

The JSR's are typically in LAD 2 (but they don't have to be), so start there first.



Another way to test if the file is being scanned,

Place an unconditional rung with an OTL addressed as an unused bit. Download it and see if the bit is on. If it is not the LAD file is not being scanned.

I suggest that a ladder logic to adjust the timer's preset time value is to be included. This maybe interfaced with a workstation pushbutton as an increase button and another push button as a decrease push button - or equivalent switches.

The logic must include: That timer should only be enabled after the preset value has been achieved. When the timer is enabled, the program execution should jump to a label in order to disable the increase/decrease push buttons rung. This should ensure that while the timer is timing, the preset value can not be changed.

fcs

I'd do a search fro T4:171/pre and see where all it is being manipulated. Could be any of a number of math statements, no telling what.

Another source could be some sort of DDE link. If you have Data Highway, or Ethernet up and running, and PC's looking at the PLC's for production reports or whatever, the spreadsheet/dbase could cause this. I had a spreadsheet loaded with my "default timer presets" that I would run after the HMI's had been tweaked to death. By resetting the timers to the defaults, I would often solve lots of troubles. All that is required for the DDE to work is a copy of Linxs and the connection. Excel works great. RSView can do the same thing, but you would suspect RSView right off, Excel, on the other hand would be hard to detect.

Just a guess. First chceck for MCR's JSR's and JMP's to make sure that your MOV statement is active. Then check for other MOV's likely after yours, or some sort of math statement that is changing it back to 1.