micrologix RTC

[MIKE31 0]

HI What is the purpose and use of RTC thanks

[gmferg 1]

Real Time Clock. This is used to trigger logic at a specific time of day or day of the week. For example, shift a daily totalizer and store a new daily total. It could be used to capture time when an event happens.

[BobLfoot 301]

The RTC if synchronized regularly with a Data collection PC's time and then pumped out to a Panelview or other HMI can be used to Time Stamp events.

[MIKE31 0]

Thanks for the reply can you give an example

[andrea 0]

I use it to turn on a feeding system 3 times a day 4:00 10:00 16:00

[MIKE31 0]

HI AGAIN what do you mean if synchronized with pc time , if is the case then is not real time clock thanks

[Clay B. 1]

AN RTC is a module that keeps pretty accurate time (like the alarm clock on your night stand). What you can do with it is bassically up to your imgination. One thing I did just today. I used the minute function (RTO:0.MIN) in a LIM function to change between several bit maps Iwas using on a touch screen. At differnt times of the hour I use different displays on my screens (it keeps the operators looking). I have used it in the past to trigger operations that have to take place at certain times. The advantage it gives you is you do not need to look to another source for time. (IE getting a timed command from another PC) Saves on coding etc....

[Guest trn_psycho]

I use a RTC in every PLC on the plant floor. They are also "synced" with a data collection PC ever hour. I mostly use these to break apart counters so that I can show stats about how each machine is running during that hour. From an operator point of view, it's nice because they can see an hour by hour breakdown of the parts run. Management likes it because they get the parts run, machine uptime, process flow, etc in real time. Maintenance uses it for error tracking and machine troubleshooting. Having it synced with the data collection pc is nice because it puts the PLC's on the same time as the shift working schedules, as well as the network pc's. (Plus I never have to worry about resetting clocks for Daylight savings time.) Also it allows you to correlate events that might happen across multiple machines.

[BobLfoot 301]

All Real Time Clock Modules I've worked with experience some form and amount of drift. Since no two RTC's are identical then no two drifts are identical. In a multi-clock system some form of sync logic makes troubleshooting easier.