RsLogix 500 Latch OTL and Unlatch OTU. Instructions to set and reset

[@TimWilborne]

CORRECTION! I spoke wrong at 3:30 about the OTU instruction. I incorrectly say that a TRUE OTU does nothing and a FALSE OTU goes and writes a "0". I should have said that a TRUE OTU goes and writes a "0" and a FALSE OTU does nothing.

[@DDLazlo]

I am enjoying this training series, Tim. You've already removed a bunch of blocks from this old sparky's thinking. I've been guilty of approaching PLC programs with a circuit mindset. Your scanning vids have broken the ice. It's easy! lol (Jk. Most things are once you "get it"). Can't wait to learn more!

[@TimWilborne]

Great to hear Richard!

[@liftedranger]

I think it's important when dealing with latch's and sealed in rungs, is to talk about what happens with power failures.

[@TimWilborne]

Finishing up the edits on it now. Next week!

[@Lil2012angle]

Thank you for the video, I was wondering what is the equivalent in CCW?

[@TimWilborne]

Set and reset, here is a video on it. kzbin.info/www/bejne/d3qnm3iVhq9nopI

[@taherkamal5203]

Excellent videos

[@TimWilborne]

Thank you very much Taher!

[@nicktoren9433]

I love this channel but this video left me asking more questions. Im that guy that doesn't fully understand the OTE/OTL/OTU instructions and how they are processed and controlled. I would like to see examples (right way and wrong way) of how you control step chains when using multiple cylinders (specifically 5/3 valves). I keep finding myself in logic loops that lock up my valves. Thanks for you channel.

[@TimWilborne]

Hi Nick. My note around 4 minutes in the video kind of hits on that. Latch and unlatch instructions are not the best way to program sequences. We've got a video series on sequence in machine steps coming out that won't help you today. Here is an article series that goes through different ways to sequence machine steps. www.theautomationstore.com/rslogix-500-training-programming-machine-sequences-to-do-an-automatic-process/

[@nisrnisr5980]

thanks for this video and i have a question what about retentive memory in rslogix 500 or how can i make memory N7:0 retentive memory

[@TimWilborne]

All memory on the SLC and Micrologix is retentive so if N7:0 has a value of 12345 and you cycle power then it will have 12345 when it powers back up.

[@nisrnisr5980]

@@TimWilborne thank you very much

[@MaNemUmar]

Out of context question but suppose we have a bunch of bits set by the HMI on an allen bradley PLC. What’s an effective, non repetitive way to set a range of addresses, to 0 after a scan cycle or user defined time frame. On Modicon PLCs, they have an IEC_BMDI block which lets you set a range of coils/words to whatever value you want. Just interested as it seems tedious resetting all bits one at a time. Im currently delving into Rslogix again. Have RSlogix micro starter lite alongside , Rslinx and rslogix emulate for simulation purposes

[@TimWilborne]

For a single word of bits you could use the MOV instruction with a source of 0 are for multiple words you could use the COP command with a source of 0.

[@MaNemUmar]

Tim Wilborne Thank you! I figured i could use MOV for clearing contiguous 16 bits (word). I’ll look into the COP instruction 🤔

[@ravindradesai5007]

Tim hello. If I use only the latch system in the ladder and not used unlatch. After switching off and On after 5 min condition of the latch will remain the same or it's automatic unlatch

[@TimWilborne]

As we say in the video, an OTL that is true goes and writes a 1. A false OTL does nothing so unless you have another instruction that writes a 0 to it then it will remain a 1.

[@nrpanneer3]

Hi, what will happen i we use more than 1 latch/unlatch for the same address ? Will it impact the latching/unlatching/malfunctioning ?

[@TimWilborne]

You can use 100 latches and 100 unlatches in the same program and it won't "malfunction". It will simply follow the same methodical program scan to a predicable result. Check out our program scan videos in this playlist plus the video showing that the last rung doesn't win, they'll help you understand how the processor will scan and execute all those OTLs and OTUs. kzbin.info/www/bejne/bIXTYmagfquApNE

[@bitterreality7920]

Hi sir! You made a mistake in explaining unlatch. Unlatch is used as if true comes in then it will say go write a zero instead of do nothing. If false comes in then do nothing. I spend whole day configuring that correct me if im wrong..

[@TimWilborne]

Yep, at 3:30 I say it backwards. Nice catch!