How to use plc clock in programming

[Ataw 1]

Hi. I am very very new to plc. Whatever i know is through google and youtube only (so very limited knowledge). I need help about how to use plc clock or real time in a plc. I am using cpm2a with cx-programmer. I need to unlatch a door at a certain time everyday. The door needs to b unlatched for 30 min at a specific time 5 days a week (mon to fri). Is it possible?

[Michael Walsh 268]

The real time clock in a CPM2A is contained in these addresses:

 Your code might look like this:

First determine if the time range is correct (This example check from 5:00 to 5:30 pm):

Then determine if the day is correct (this example does Monday through Friday):

[b.k.n. 3]

You might want to check out the MOVD instruction in case you want the format different. For example if you would like the hour to be first and then the minute be last in the word. Or if you would like to just have the minute only or hour only displayed in a word. The example i have would transfer just the hour into DM0.

Edited 10 Jun 2016 by b.k.n.

[BobB 58]

Use ANDW as a mask - ANDW #00FF or #FF00  AR19 D0 - easiest way to separate hours/minutes/days/month/seconds.

[b.k.n. 3]

Thanks i agree easier way thanks. Now i have one question am I correct that if i mask it with #FF00 and for example if AR19 = #1925 the results in DM0 would be #1900. I would tend to think most people would like those results over in the right two digits and not the left two. I guess you could divide DM0 by 100 and get them moved over to the right two digits. Let me know if I'm wrong and thanks again for that ANDW idea.

[Michael Walsh 268]

b.k.n.,

You are correct in your statement that a BCD divide by #100 after the ANDW instruction would also do it. 

This is CJ2M Code so that I could simulate, but would be very similar in the CPM2A PLC:

Ataw,

Also, I wanted to point out in my original example that the upper 3 bits of A21 are in fact used, but it seems that they are output bits, so unless you assign a coil to them, they should all be off.

[Ataw 1]

21 hours ago, Michael Walsh said:

The real time clock in a CPM2A is contained in these addresses:

 Your code might look like this:

First determine if the time range is correct (This example check from 5:00 to 5:30 pm):

Then determine if the day is correct (this example does Monday through Friday):

Thank you Michael Walsh I will try to do this at work today then lets see how far I can go. 

[Ataw 1]

14 hours ago, b.k.n. said:

You might want to check out the MOVD instruction in case you want the format different. For example if you would like the hour to be first and then the minute be last in the word. Or if you would like to just have the minute only or hour only displayed in a word. The example i have would transfer just the hour into DM0.

Thanks b.k.n .

[pfort 20]

4 hours ago, b.k.n. said:

Thanks i agree easier way thanks. Now i have one question am I correct that if i mask it with #FF00 and for example if AR19 = #1925 the results in DM0 would be #1900. I would tend to think most people would like those results over in the right two digits and not the left two. I guess you could divide DM0 by 100 and get them moved over to the right two digits. Let me know if I'm wrong and thanks again for that ANDW idea.

That is why I prefer the ANDW instruction. 

1 instruction instead of 2.

[BobB 58]

They go into the right 2 digits for hours anyway. I generally only have to extract hours. If you are extracting the left 2 digits Michael's solution is the way to go. ANDW just makes life easy.

One of my favourite instructions along with BCNT and APR - so useful and nor available in most PLCs.

[Ataw 1]

On 6/9/2016 at 2:35 PM, Michael Walsh said:

The real time clock in a CPM2A is contained in these addresses:

 Your code might look like this:

First determine if the time range is correct (This example check from 5:00 to 5:30 pm):

Then determine if the day is correct (this example does Monday through Friday):

thank you Michael Walsh and everybodr ru

[Ataw 1]

thank you Michael Walsh and everybody else. very busy at work so only yesterday got a chance to look into this project. it works perfect according to our needs. this place is certainly a great help for guys like me who dont have any back ground qualification for plcs and are just getting started. I will certainly keep coming back to learn from you guys. once again i thank you all.