Are pins advanced or returned?

[jonesy29847]

I have worked for a tier one supplier for over 14 years. Our convention with respect to locating pin nomenclature has always been the pin is advanced when it is ready to receive a part and retracted at some point in the cycle to facilitate part unloading. We are in the process of building another plant and the company that is doing the controls engineering has swapped our convention using the following logic.

1. The home (returned) position is always the opposite of the work position.

2. The work position for a pin is retracted, therefore the home position is extended.

The issue that I have is the HMI now indicates the pin is returned when it is ready to receive a part and therefore extended. I have had to change the HMI nomenclature from advanced to returned in one of our plants to suit our convention and the assembly supervisior.

I can also argue that a pin is somewhat different than a slide or clamp in that its work and home position are the same.

What are the conventions you have worked with, I would like to hear from OEMs and endusers.

Thanks

 

[lrob]

I have only been doing machine control for about five years. I have ten years of control experience. When I write a program I like the nomenclature to match the physical state of the part. In your case, if the pin is protruding out, I consider this extended. I like this because any operator or troubleshooting can be done from physical state. If the HMI says extended, then the pin would be out, this keeps it simple.

 

[jonesy29847]

Thanks Irob, are you an OEM or end user?

 

[lrob]

I am both. I am an Electronics Tech at plastic extrusion plant. However I was helping a small system integrator for four years trying to grow his company, until I had to return to plant maintenance. I still do part time programming for a custom machine builder. This machine builder uses alot of moving parts ie. cylinders, clamps, sprint markers, stepper drives. So I know both sides of the situation. As I said before as a tech I like the physical position of the part to match the HMI. If a cylinder is extended I want that to be the way the display nomenclature is. From a design and programming standpoint I lean toward what makes the operator and technicians job easier.

 

[eriond]

It sounds like it is time to start dictating nomenclature criteria to the integrator. The customer (the guy paying the bill) is always right.

 

[jonesy29847]

eriond, I couldn't agree with you more are you an OEM or end user? If you are an end user what is your convention, if you are an integrator what do your customers do?

 

[eriond]

cscott@haierus.com

 

[eriond]

I am an end user to integrators and an integrator for customers inside my facility. In my projects, I will ask the customer how they would describe the possible positions of a device, for use on a display. After all, it is only a label on the HMI. Normally, HMI's are used by operators so the labels on it should be the ones that make sense to them. The bit/word descriptions, in the PLC program, is another matter altogether! When using an integrator, I normally spec out HMI's and displays that I have knowledge of. If the labels they have assigned are confusing to my customers, I'll change them.

 

[Tom001]

I couldn't agree more, I was recently working on a program on a small clip-fitting machine, and also found that the guard locking shotbolts were referred to in the I/O list as out (but this was the locked position) and in (which was the unlocked position), confused hell out of me as I only wanted to add a solenoid locking guard switch to the machine as we did'nt have the correct spare part to replace the broken one.