RSLogix 500 program problem (ML1400 and PV+600)

[rQx]

Hi!

I made an addition to an existing program.

There are already configured communication between the PLC (ML1400) and the HMI (PV+ 600) regarding the system time.

My mission was to create a function that will ultimately result in a value change that I wanted to log. This would happen 12:00 every day. As I do in siemens I created compare blocks that compared the time and when the hour, minute and second was correct it would latch a tag. This would be active for one second (since I compared to seconds aswell). I noticed at the site that this didn't work, I reprogrammed it to hours and minutes and used a ONS. I still had a slight delay in the program though.

I have now digged in to it and I thought that maybe there was a communication delay between my hardware. I went in to FTView Studio and looked at global connections, here it says that the Time and Date output interval 10sec. Does this mean what I think it does? And why isn't it updated more frequently? Would it hurt to update it like every 0.5 second?

 

[Ken Roach]

You can update the Date and Time output as fast as you wish; it will just take a little more bandwidth.

But I've never been able to get accuracy any better than 2 seconds with the Global Connections feature. It just wasn't built to do things in the 1-second range. I haven't done any experimentation with it on v6 or v7 firmware terminals.

 

[rQx]

Alright, this bandwidth can't be to big thought so I guess I can lower the update interval. Thanks alot Ken, really appreciate it!