AB Ladder Logic Issue

This architecture looks like ERP→Panelview→operator→tank system, with the chance for operator error in copying the ERP request. Can you do it more directly as ERP→tank system, with the Panelview displaying the choice but the operator at most pressing a start button to begin the transfer (or whatever happens)? Just a thought.

The operator will enter an order number... At that time the panel view will be populated with a product # the operator will then pick where he/she will get the material from ( tank 12) and where it is going to (scale 3). I am building into the plc the interlocks to keep him/her from drawing from the wrong place and sending to the wrong place.

thank you for your ideas.. no idea is a bad idea.

John Lyons

You say you have 18 vessels to choice from! Is the product that is stored in each of the 18 vessels always the same materials? Data entry upon receiving an order is place into some type of format I assume, to the main frame. I have in the past used code from order entry to build recipes for processes in the PLC. In doing so have reduced errs to order file only. But, allot of this depends on your systems capability. Bar coding orders works well and can be read into PLC as well. Talk to your MIS personnel (if you have them on site) and see what formats can be produced. Might save everyone some time and effort.

Not knowing all of the details makes it hard to give a really good suggestion here. But maybe this helps you in the thought process. Good Luck.

Thank you

Assign a numerical value to each of your materials in the vessels.

Restrict the operators choices on the panelview per product code to the vessels containing the correct material.

Provide operator feedback when an incorrect choice is made.

All the vessels have a dedicated # for the products in them and had a strict sign off procedure to change. Example... vessel 1 has item 1234567... ERP system sends item 1234567 to the panel view and I display it. The operator has to pick the vessel. If he picks vessel 1 he is ok, if not I clear screen and he has to start all over again. He also has to pick what weight scale the material will be going to. That has to interlocked also... or by the way, there is always a by the way, 2 vessels may have the same product with the same code in it... sorry

I was just trying to minimize my code... is there a way that I can compare the ERP value to all the values in the vessels, then look at what the operator picked and say yes or no?

John Lyons

What programming language does your ERP system use?

Is you "panelview" an AllenBradley Panelview?

Does you system use a PLC - if so, what manufacturer (AB, GE, Siemens)?

The ERP system send data to a excel spreadsheet. I pull the data from the spreadsheet and send it to my A & B Plc and Panel view.

Since you already have the codes for each tank stored in your PLC as integers, you should be able to use an EQU instruction to compare the value stored as a product code for the tank to the value entered by the operator on the Panelview. All that you should have to do is insert an EQU instruction as condition for energizing each of your 18 valves or whatever outputs are used to let materials flow into your tanks.

Your next problem will be figuring out how to ensure that the operator enters the correct product code on the Panelview before selecting which tank to use.

I agree... I want to minimize my plc programming.. I have 18 vessels and 12 possible scales to select... that is a big matrix and allot of code.. that is why I was wondering if I could search and compare....