Unitronics M91 Logic issue

Anyone familiar with Unitronics 'U90' programming? I have been struggling with what I thought would be a fairly simple logic project, but it keeps kicking my butt. I'm thinking that what I'm trying to do isn't possible with such a simplified programming environment. (Or, I'm completely over-thinking the whole thing!)

I'll post the project if someone cares to take this on... Thx.



~Mike

I'm glad to say its been a long time since I had to work on Unitronics
and I don't have the U90 installed on this PC but if you want to throw a question this way I'll have a crack!

Hi

I am not big fan of Unitronics.But M90 line is the simplest PLC they have.Maybe you need something more powerful.

Well... the problem isn't so much the U90 software or the M91 device itself, (although both aren't very powerful) but rather the logic that I'm trying to do. Here's the problem:

I'm using a rotary encoder to measure the amount of steel that comes out of a 'roll feed' before going into a punch press. The reason for the measurement is that the coil of steel has 'known defects' in the material, and they want to allow the PLC to force the punch press to only run in 'manual' punch mode while a 'defect' in the material is present. The steel mill provides a list of the known defects with each coil, which could be as many as 10. (Usually only 3 or 4) The operator of the press will 'enter' the start and end points of those defects into the PLC when a new coil is loaded.

I got the measurement part working, and the 'data entry' part working, but the trouble comes in when I try to mark the 'end' of the final defect and allow the PLC to signal the press that it can run in Automatic mode. I think it's because I'm comparing a variable to a 'Zero' which might be at the end of defect 4 or 5 or 6 or... so on. The software can 'jump' to a label and 'loop' back if necessary, but not based on the 'value' of a variable; only text labels are allowed.

The most recent version of the many that I've tried is attached... you'll need the U90 software (free) to open it.

Hey Steelblue,

I'm comparing a variable to a 'Zero' which might be at the end of defect 4 or 5 or 6 or... so on

Click to expand...

Not sure what you mean by this?

Where in relation to the punch where are you measuring with the encoder?

what I would (Have Done) have thought would work is:

If Num_Defects = 1
If Encoder_Value >= Start_Defect1 < End_Defect1 Then
Auto_Punch=0
Else Auto_Punch=1
Else If Num_Defects = 2
If Encoder_Value >= Start_Defect1 < End_Defect1 Then
Auto_Punch=0
Else Auto_Punch=1
Else If Encoder_Value >= Start_Defect2 < End_Defect2 Then
Auto_Punch=0
Else Auto_Punch=1
End

And repeat for as many defects that were entered?

Frosty said:

Where in relation to the punch where are you measuring with the encoder?

Click to expand...

The measurement isn't really related to the actual 'punch', but instead it's to determine the locations of the defects in the steel. The coil of steel could potentially be several thousand feet long, and the defects could be anywhere along that distance.


Thanks for the response... It's worth a try! (I did mention that I'm probably over-thinking this whole thing)

~Mike

I got this figured out finally... the guys at Unitronics gave me some help and some good ideas to 'trim' the ladder down to a better running project.

It was just a matter of getting the 'compare' functions in the right order and sequence.

Thanks

steelblue48310 said:

I got this figured out finally... the guys at Unitronics gave me some help and some good ideas to 'trim' the ladder down to a better running project.

It was just a matter of getting the 'compare' functions in the right order and sequence.

Thanks

Click to expand...

Belated Greetings! I'd love to see the code for your final results. I happen to use Unitronics whenever I can (I usually do not get to choose...). Not only because I support Israel, but I have to admit, the software is free and the tech support for me has been superb. Even if it goes after hours, the calls are forwarded to Israel and they speak English.

I had a Cut to Length application and I used a V350-TR20. I would use them more for small stuff if they'd make just a PLC without the HMI. I seldom need an HMI for new development. I'm retired and just do consulting on existing, usually Legacy, systems.

I'd be real interested in seeing what you did with the M91 / U90.