Multiple start buttons

[rdrast]

Keith, that was sort of my point. Still a single Start button, but the similar functions of Jog/Thread can be anywhere.

We do have a few lines around here that do have multiple "Line Start" buttons, but that is the exception rather then the norm.

The reason that most lines here do not have multiple start buttons is just that on an actual start up, there are way too many things that the operators need control over, Line speeds, Pressures, Levels, etc.

All of our lines return to a zero speed setpoint on Stop, so being able to 'Start' them from anywhere would require many more duplicate controls/HMI's. Thread/Jog take care of that problem by having a slow, fixed, pre-programmed speed and conditions when engaged.

 

[kamenges]

I'm in the web handling game. In general, unwind / process / rewind. Quite often there is no auto transfer. We typically will have a start button (either through an HMI or a hard button) on each end since those are the operator-intensive locations. It allows the operator to start the machine after a roll change regardless of which side is changed.

This is where the dichotomy comes in. Our machines are usually small enough that the operator has a full view of the whole machine from anywhere around the machine. So the operator would be able to see if he is putting someone in danger by pushing a start button. However, this same physical layout would contra-indicate multiple start buttons since the operator wouldn't need to go far from any given point to reach a single start button. Go figure.

Having said that we have never had anyone tell us that multiple start buttons the way we use them on our machines are an issue of any kind.

Keith

 

[TheStarr]

How about an interlock key for the panels. Multiple panels, but only one "enable" key that the operator takes with them when they leave the primary station.

If you don't have the key, you can't move anything.

We use a similar setup as a safety system around our larger robots.

 

[Lancie1]

1) Each control station shall have a separate manually actuated start control device.

4) All start control devices shall be actuated concurrently.

I think it means, that if there are start control devices on a control panel for a particular machine or function (such as 2 or or more start buttons, then arrangements must be such that all of the "start control devices" get actuated at the same time. For example, if for safety reasons, a start control has two buttons that need two hands to press.


This does not mean that you cannot have another control station somewhere else with another start button, or multiple buttons, that get pressed when other control station start buttons at other locations do not get pressed.

This whole rule applies to multiple control stations, but the individual sentences only apply to ONE control station. For example, this sentence:

On machines requiring the use of more than one control station to initiate a start, ....

The very sentence itself admits that there are machines that require the use of more than one control station. Given that, what would be the point of "more than one control station to initiate a start" if you cannot have more than one start button? So don't mis-construe the rule, it does not prohibit many independent start buttons at multiple locations. Read it as if it said this:

All start control devices on any specific control station shall be actuated concurrently.
.