Discussion...On controlling a Robot via PLC

taward31 said:

Hey Everyone,

I have a project that involves controlling a Abb Robot there is also a siemens plc and HMI and a Omron Vision controller,

The project has been done previously by the company I work for.

The only difference is that this time I am integrating vision to speed up the process.

The old code literally only uses the PLC for recipe selection via the HMI and Fault status and resolution etc. Basically the robot sequence is programmed entirely in the Robot controller

What I would like is people's opinion on what way you would approach this project,

My thoughts would be to control the robot via the PLC being a master.
I.e Calling small sub-routines via a PLC sequence and waiting for them to be completed before moving on.

Is there any major advantages/Disadvantages in either method

Thanks in advance

look forward to hearing you guys opinion

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Liam Moran said:

I set up robot cells all the time, and I make the PLC the master always.
My main objective is to keep the operators away from the teach pendant, and give them a user friendly interface on the HMI with whatever they need to run the cell. The robot controller controls only the movements, all the decision making I do in the PLC.
If you are going to use vision, then you possibly need conveyor tracking too which is an expensive option from ABB.
What model of robot are you using?

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jstolaruk said:

ABB has a software package option called IFWC Frameworks that some of my customers use with Siemen's PLCs (actually any PLC that can be a support a fieldbus). The idea is that the robot is used the same way a simple servo is used; strictly for moving from one point to another, albeit the robot has multiple servos allowing complex pathes. All logic decisions are made in the PLC and thus decides when the robot makes the next move.

Example: From a HOME position, the PLC decides when the robot should move to a POUNCE position, tells the robot to move to the POUNCE position and the robot stops and waits for the next command from the PLC. The PLC makes the logic decision to move to the WORK position and tells the robot when its okay to move. Etc, etc,etc.

The idea is that the PLC is much better suited to make the logic decisions that a cell needs for handling materials and easier to edit. The robot basically gets turned into a glorified servo controller, with its only responsibility is to move from one point to the next. Even the control of any End-of-arm-tools is controlled by the PLC. Robot projects that I do with Ford, GM, and FCA all use the same idea and Ford will most often specify to use Frameworks, GM has their robot template that is very similar, and FCA is okay with rolling your own but requires the same architecture.

Hope this helps.

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