Created Date: December 16,2009

Created by: Tinker

Well, in the "address picker " all the RTC registers are marked read only. That seems like a flaw to me, no clock in a lowcost PLC is going to be totaly accurate and it is forseeable that it will have to be reset at some time. Maybe they were thinking that since the software is free people will just use the programing software to set the clock, but I'm guessing that your custodian won't be too thrilled with that option. Anyway, since the C-mores are not free, wouln't AD want to give you as many reasons as posible for buying them?

As far as daylight savings time, you could just add 1 or 0 hour as needed after you read the RTC hour register, without changing the RTC itself.

I suppose one could also add or subtract an offset to adjust the time for clock drift too, but that seems like a hard way to set the clock.

Created Date: December 16,2009

Created by: jonesjeremya

Maybe i'm looking at this the wrong way, but can't you just make a clock in the ladder using time bits to increment a register? Say, in military format with a reset on the register(s) at midnight? In that way you can adjust the time from the HMI and the daylight savings can be toggled when needed at the appropriate times in the year. I don't know how accurate the time would be over an extended length of time?

Can it be done through the ladder?

How accurate would it be over time?

Sorry, I have not done applications that are based on time, so I do not know first hand, but my idea seems conceivable, to me.

Jeremy

Created Date: December 19,2009

Created by: DetroitSound

Thanks for all the interest. I do like the idea of using two counters for the clock; I 've long been a fan of using counters for long duration timers.

You 've mentioned that before and it was something I never even thought of - a timer is a timer; a counter is a counter and never the twain shall meet,right? Wrong. But it has proven to be a great way of doing it. I thank you.

Created Date: December 19,2009

Created by: Rich19551

You 've mentioned that before and it was something I never even thought of - a timer is a timer; a counter is a counter and never the twain shall meet,right? Wrong. But it has proven to be a great way of doing it. I thank you.

With all the talk about clocks I thought I would try something different. I haven't tried it but it should work. Don't know it would work with Click (I would have to read up on it).

PLC 05

// Rung 1

// Address 0

STR SP1

STR C0

TMRA T0 K600

// Rung 2

// Address 5

STR T0

PD C0

// Rung 3

// Address 7

STR C0

INC V2000

// Rung 4

// Address 10

STRE V2000 K60

INC V2002

LD K0

OUT V2000

// Rung 5

// Address 16

STRE V2002 K24

LD K0

OUT V2002

// Rung 6

// Address 20

END