Need Example of Block Transfer Program

Quote by Ron
"for anyone who’s interested in the issues involved in this thread, I’ve just confirmed all of the statements above with the real-world hardware in my lab ... maybe this will be helpful to someone someday ..."

can you post the *.RSS from your lab for our future reference.
Thanks
Mickey

Greetings Ken,



do you already have an answer for that “swap-the-module” puzzle? ... I don’t have a 1746-NI8 available to experiment with so anything that I’d post would be sheer speculation ... but it’s certainly an interesting question ... I’ll do some “book” research on the task the next time I get some free time - unless you post something in the meantime ...



Greetings to Mickey,



I’ve attached the .RSS file that you requested ... but I’m sure that you’re going to be disappointed ... there’s nothing in the ladder except for the two block transfer rungs that I’ve already posted ... remember that all I was trying to do was offer a “getting started” example to move the project in this thread off of the “top-dead-center” position ...



but your request does bring up a scary part of working with some of these “Remote I/O” issues and other things like them ... specifically, a LOT (most?) of the settings that make the system work are NOT included in the .RSS file ... I’ve had several cases over the years where a customer has assumed (gosh I hate that word) that simply downloading the program to a processor would automatically cure every conceivable ill that the system might encounter ... of course that’s just not so ... if the DIP switch settings get scrambled somehow/someway/someday then a program download is just a drop in the bucket ... along the same lines, the jumpers inside the 1771-IFE analog modules on a PLC-5 system are notorious for causing trouble like this ... many technicians don’t even know that the jumpers are inside there ...



jumper positions and DIP switch settings are items that should be carefully recorded and safely stored away just in case they’re ever needed ... a few minutes of pencil work can sometimes save hours of frustrating effort ... another idea is to record the settings in a spare rung comment at the top of the ladder file ... hopefully that would keep the information handy ...



but anyway ... here’s the program - just because you asked ...

do you already have an answer for that “swap-the-module” puzzle? ..

Click to expand...

I know the answer, because I've had to do it, but I don't have a ready made ladder to post.

I can provide the answer if you like, I can just post the answer in text, or if I have time I can provide a sample ladder.


Ken

All points well received. Thanks

Mickey

Sorry Ron, I got the dip switch settings from a drawing. These panels are not wired in yet. So, I will be able to change the dip switch settings myself. I thought that the drawing was right when I posted it. Also, you asked how long I've have been working with PLC's. I just started and I have no experience (my boss knows this). I have been reading manual after manual, but I’m a bit overwhelmed with all the new information and I was just asking for some help from you guys. Sorry, to waste your time and putting so many posts online. I’m not just trying to get the answers without reading or trying myself. How did you guys learn when you first started? Also, we don’t have any equipment in the office to test our programs etc. I do plan on taking a course but, none are offered till next fall. Hopefully, I make it here till then. Thanks for your patience. ~Amy

Greetings to all,



I’ve just spoken with Amy by phone ... and she is indeed a very nice person ... we’re exploring ways to help her with the PLC learning curve ... she sounds as if she’s more than willing to put in the effort necessary to learn this stuff - but right now she has a LOT on her plate ... the project in this thread is just a tip of the iceberg ...



hopefully this will turn out to be another PLCs.net success story ...

Thanks for everyone's time and help. Ron has been a great help already.
~Amy

Amy,

I started working for the company I work for now about 15 years ago. I had no knowledge of PLCs or even computers for that matter. My experience was mostly with relays and general electrical wiring. We then proceeded to get a job that would require an AB PLC5 and some type of HMI. In a few short weeks I had to buy a computer, learn how to use it, learn how to program a PLC5, and learn an HMI package. I did basically what you are doing, ie reading the manuals and asking for help wherever I could get it. I did attend an AB programming class and I used tech support quite a bit. There was no internet or plcs.net back then. This is definitely a great resource. And like you I had to learn Remote I/O and Block Transfers. I know what it is like to be thrown into the fire many times. If you have the time I think it would be helpful to take a programming course. However if you do take a course make sure they cover the stuff that you need help with. I attended an introductory course on "Programming the PLC5" and the main thing I wanted to learn was about block transfers. But, guess what, when I got there I found out that block transfers was only covered in the advanced class.

Be persistent and keep asking questions and you will get your answers eventually.

Randy

another way to slice the pie ...

Greetings Amy,



after the further update on your actual hardware from our phone call, I’ve gone just a little bit further with the DIP switch settings for the 1747-ASB modules ...



suppose that we set the 1747-SN/B scanner up like this:







and suppose that we keep the hardware set up the way you described over the phone ... double-check this figure and make sure that I understood you correctly ...








if the figure is correct, then you could set the DIP switches as shown above ... this would give you convenient access to the empty slots - just in case you ever need them in the future... with this set up, the Block Transfer rungs for the two 1746-NI4 modules would be the same as I attached in a previous post ... and the “N11” addresses of the analog input channels would remain the same as in that previous post ...



this is probably the best way to go, based on what I know (or think that I know) about your project ...



but ...



just suppose that you could move each of the 1746-IA8 modules as shown below ... and suppose that you leave the three extra slots at the ends of each chassis empty ...








with that arrangement and with the DIP switch settings shown, things might get a lot easier for you ... specifically, you could make use of the scheme mentioned on page 3-11 of this manual ...








this means that you wouldn’t need any block transfer rungs at all ... specifically, the analog addresses for the 1746-NI4 in slot “L” would simply land right on the processor’s input table like this:



Channel 0 = I:9.16

Channel 1 = I:9.17

Channel 2 = I:9.18

Channel 3 = I:9.19



and the analog addresses for the 1746-NI4 in slot “S” would land on the input table like this:



Channel 0 = I:9.24

Channel 1 = I:9.25

Channel 2 = I:9.26

Channel 3 = I:9.27



this would be a lot easier for other technicians to work with too ...



the downside of this “no block transfer” arrangement would be that any future use of the “extra” slots at the end of each remote chassis would require some major modifications (addressing changes, etc.) to your program ... on the other hand, if you don’t think that you’ll ever need those slots, you might consider swapping the two 7-slot chassis that you have for smaller 4-slot types ... you could use the larger ones on a future project ... just something to think about ...

and incidentally, the addresses of the 1746-IA8 module in slot “N” would be I:9.20/0 through 1:9.20/7 ... and the addresses of the 1746-IA8 module in slot “U” would be I:9.28/0 through 1:9.28/7 ...

anyway ... keep us posted on how things are working out ...

PS edit ... I just read your e-mail information but I haven't had time to go over it ... it would be a good idea to post everything about your system on the open forum ... there are many people here who can help ... just check with your boss first about any proprietary issues ...

my 2 cents worth

I don't know any of the details of this project, but you have to assume someone, somewhere, specified those 7-slot chassis for a reason. So, if it was me, I would go ahead and implement the block transfer method with single slot addressing, it will save a lot of work in the future if you ever do need to use those empty slots.

It sounds like this is a new installation, and there will probably be more time for de-bugging now, than in the future when someone needs to make a "minor" modification and add a few I/O modules.


Keep up the good work Ron.


Regards,
Ken

Greetings Amy,

the scaling numbers you're looking for are:

from page 4-6 of this manual ...

Thanks again Ron, I appreciate all your time and patience. ~amy