Implement Lookup table in RSLOGIX5000

Hi all,

I would like to generate a lookup table (Time vs Speed) or (Position vs Speed) in rslogix5000, and looking for some idea on how to implement that in ladder logic? which instruction can help me do that job?

Appreciate any feedback in advance.

Thanks

Take a look at the FGEN instruction.

the FSC instruction. File Search and Compare

Thanks,

Is there any document that explain how to implement that? any example?

In the sample program folder there is a Look_Up_Barcode example.

You can also Search the forum. look at bottom of the page you'll see a search box. Search Chart or FSC you should get plenty of hits.

also the Instruction help file in RS5000 has a good explanation.

Your situation sounds like you want to find a number (time) figure out what position is that number is in the array. Then use the position number found as an Indirect address for your speed array. Once you capture your position just use the (RES) instruction on the FSC ( just like you would on a timer or counter ) to get ready for the next lookup.

Hi, Thanks a lot it was really helpful. I got it work.

another question, my Array contain 10000 elements speed and 10000 position, do I have to enter each value manually ? is there an easier way to do it?

Thanks,

I had a similar application a little while ago, where I had to enter recipe data for 300 recipes. Each recipe had 6 parameters. If you have a copy of excel and an RSLinx Professional license, it can be done very quickly and easily using DDE Poke.

Check out this thread that I posted on the topic, which includes a link to a good article about DDE Poke, and the code that I used to make it all work.

If you have a full version of RSLinx then you could use DDEPoke and Excel. But unless you numbers are sequenced then Excel will not be any quicker. You still have to type them all. Search forum for explanation and examples.

You can save program as .L5K file, open in notepad, find the Array and start typing values separated by commas. The Array name will have 10000 comma separated zeros that you will have to replace to maintain array size.

If you have a PLC available then you can create a rung of logic to enter values into your array using indirect address method.

Add MyValue Chartincrement MyValue

MOV MyValue MyArray[myindex] 1

Add Myindex 1 Myindex

use one shots to trigger.

edit:got phone call in middle of posting. didn't see ASF posted DDE option

In the past I have used the FGEN for a non-linear relationship, that said it was around 100 lines and not 1000 so storing/typing the data into the PLC wasn't an issue.

Is your Time v Speed or Position v Speed not linear?

If it is, you can just scale the values.

Hi AFS,

Thanks a lot, that is exactly what I am looking for, however I have an issue here I copied your code to my excel sheet Macro VBA,and configured a new DDE topic called EXCEL, and and went online with my controller, and tried to transfer the data from EXCEL to control logix it shows me an error, my sub/function (opernRSlinx() is not found.

is there any document that explain how to do that? what did I miss?

Thanks for your response in advance

RSLinx help file has VBA information. Just look for DDE

oh, Thanks, but what I realy want to learn is VBA, I have an issue that my program couldnt see the openRSLinx() function.

Thanks

noorloai said:

Hi all,

I would like to generate a lookup table (Time vs Speed) or (Position vs Speed)

Click to expand...

This doesn't make sense. Speed vs time or Position vs Time makes sense.

in rslogix5000, and looking for some idea on how to implement that in ladder logic? which instruction can help me do that job?

Click to expand...

Why not use a cam table?

[/QUOTE]

Agreed; what OP is describing sounds exactly like a motion control cam table.

Ten thousand elements? That's a pretty long cam. I'm willing to bet that quite a few of the points in it could be substituted by interpolated points.

We have had applications where we had data for every 6 inches around a race track of 2 to 2.5 miles around. We had to have 4 cams, 1 for each tire. It was for a race car suspension testing machine for Nascar race cars. Just about every racing team has one of these machines.

Now back to the thread. What really is sad is that the OPs always want to know how to solve what they think is the problem. They rarely state what they are really trying to do so we can see the picture. Too many OPs think they are the first ones to come across their problem when it has been done many times before. On top of that many OPs don't understand their problem.

It may also be possible to fit a polynomial to the data.

If it is math for motion control I have probably done it before but how can one help when there is no good information and the problem is stated incorrectly?

Honestly guys, there are a lot of threads I ignore now because I don't have the time to ask questions only to get answers that don't make sense.