Clutch/Brake Control

Help, Please,

We have to bid a project to replace old magnetic controls with PLC based controls on a punch press. It is a Single Stroke / Continuous / Inch type control--brake monitor, motion detector, etc. I have experience years ago with the old type magnetic controls with dual palm buttons, anti-tiedown anti-repeat stuff.

But I seem to remember a redundancy reguirement if using PLC's in such an application.

Can anybody point me in the right direction to get the required safety information we need to design such a system??

thx

We use a combination of the optical touch buttons and safety relays that Banner sells for our Punch Presses. The PLC is mainly used for cycle conformation, data tracking, and alarming. I know OSHA has specific guidelines on this but I can't seem to find my info at the moment.

You might also want to take a look at these sites.

http://www.osha.gov/SLTC/etools/machineguarding/presses.html
http://www.osha.gov/SLTC/etools/mac...twohandcont.html#Two-hand Control Regulations

I suggest you to think well of all the safety issues before you submit any bid for this project.
Do not attempt to do anti-tiedown with PLC unless it safety PLC.
You might need safety relays, saftety curtain.ect
It expensive stuff.

Just to let you know,

Pilz and Seimens both do safety PLCs that should fit your requirements. In fact, I think the Pilz PLC was designed with presses and punches in mind.

Both have built in redundancy, and if wired and programmed according to their instructions, should need no interposing safety relays.

Doug

you have not clearly mentioned about your application. one simple design is that by using electromagnetic clutch & brake it is possible to control the motion. and these clutch & brake can be activated by the plcs. and the signals can be given from suitable sensors & actuators to the plcs.

Thanks for all the feedback, guys. That's enough good information to give start to my research phase of this thing. I'll most probably seek more advice as I get into it further. I'll let you know what we decide to do. thx again.

A-B make (or at least used to make) a module specifically for this application - the 1771-PM.
I don't know any details except that they had to be used in pairs.
I think they also produce(d) a SLC version of the module/system.

Here is a link to Wintriss. My background is in punch presses and we like this brand best. We used to write our own program for our presses but OSHA and others have requirements greater than we cared to attempt so we started purchasing the controls. OOps, my link is no good. Please search for Wintriss.

This link is probably what you are looking for.

http://www.helminstrument.com/

I use the resolver module not the press/brake. So do your homework first.

The following link should get you to the Wintriss site.
http://content.honeywell.com/imc/wintriss/products/smartpac.stm

Well,

Install is growing ever so closer.

We decided to go with the "Press Room Electronics" Short stack version of their Press Commander controller. It's a redundant cpu and i/o type clutch/brake controller and exceeds OSHA 1910.217 and ANSI B11.1-2001. All it does is control the press modes (inch, single, cont, off) and the clutch brake.

We're also including a MLX 1500 and quickpanel touch screen for mminor stuff and alarm annunciation. There are redundant safety interface relays for the e-stop circuits and all guard safety switches.

I have one big question, though. I've looked through the NFPA 79 document but can't find a clear answer.

Can I start the main drive motor for the press through the touchscreen?? This motor turns the fully guarded flywheel but initiates no press die fixture motion. NFPA 79 says I can control the starter via a PLC output and even gives example diagrams for that, but mentions nothing of the operator controls--except for the PLC inputs for start/stop are on the same diagram as the outputs. I am planning to start the vacuum motor and ejector motor via touchscreen and all motors are hardwired off in case of an e-stop.

It seems to me that if I can use a PLC output to control the starter, it would make no difference if a button was wired to a PLC input or via an rs232 port.

Does anybody know?? can anybody point me to some info about this issue??

The reason is that the customer (and I) wants the pane less cluttered than the 22 operator switches on the present non-compliant controller. I've got it down to 12, including the e-stop, dual cycle start pb's and the necessary hardwired operators to keep the clutch/brake controller compliant. I would hate to add two more for the main motor.

Help, please