Hello guys,

I noticed that their is a clock inside a CPU (SLC500/04). When I set up a rack RSLogix 500 makes you choose the CPU first and then we can either let the software update the rack's content or import each card from a list. There I noticed that their is a tab for the clock.

The plant I work in is not that big but there are numerous clocks and neither has identical time and as I have to work throughout the entire plant it ends up being troublesome to time jobs. Also employees have reason all the time because they take more break time...

I have a PICO with a clock 1746 L12BWB and I'm using it to turn on and off lights for the beginning of a shift and the end.

Can I use, SLC5/04 with a DC output cards to light up segments of a four digits to make a LED clock?

I wonder which command to use to read the clock like TOD or FRD.

Thank you.

You just use MOV instructions to move the value in the S2:xx register for Day, Hour, Minute, etc into a holding register, or examine it directly with instructions like EQU, GRT, LES, etc.

I don't know if I'd use an SLC as the master clock for a facility unless I could set it frequently. They are about as accurate as any other simple clock like a digital watch; they can drift a few seconds per month. Sometimes they drift more when they're running especially hot.

There is an RSLogix 5000 Clock Update Tool that runs as a Windows utility and sends the computer workstation time at scheduled intervals to Logix and PLC/SLC controllers on a network. If the workstation it's running on is also synchronized to a good quality time reference (like the NIST clock on the Internet) then you can get and keep very accurate time in your controllers.

I was recently in a big machine shop that had a 50" flat-screen television mounted outside the part scheduling room with nothing displayed on it but an analog clock face. I'm sure it does something else, but in the three days I was there I never saw anything but the clock.

TOD converts a number into BCD. Useful if you have a BCD LED interface. However, by the time you buy all those output cards, check out Red Lion's G30x display series and the "BFD" display. This gives you the capability of doing much more than a clock, the programming software is free, and it's easier to program and has fewer bugs and hardware failures than a Panelview Plus. The cost will probably be less than all those output cards for LED's and the LED displays. Another option is a marquee display (check out ezautomation ezmarquee) which can easily interface directly to the PLC but is a little more complicated to program.

A word of warning. Many of these panel devices have internal clocks and don't need a PLC for the time. Whenever possible, I try to set it up where ALL machines always have clocks somewhere on their screens. The purpose is two-fold. First off, operators are used to it and like having a clock. Second, the clock on the panel directly reads the clock on the PLC (NOT the internal clock on the panel if it has one), displaying down to the second. If there is a communication problem between the panel and the PLC, or the panel "locks up", the clock stops. So it's a built-in troubleshooting tool.