Subject: RE: PMP> cover -v- interlock

From: Bob Pentecost <[email-masked]>
Date: Mon, 10 Mar 1997 10:40:26 -0700

I like the portion of Don's message that says an interlock is open when "a 
condition that prevents or has stopped printing due to some mechanical 
irregularity." This seems to encompass many conditions (Gail's, Don's and 
Angelo's) without the requirement that the interlock is to "prevent injury 
to a human."

Bob Pentecost
HP

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From:  Don Wright[SMTP:[email-masked]]
Sent:  Saturday, March 08, 1997 4:58 PM
To:  Bob Pentecost
Cc:  'PWG-pmp'
Subject:  RE: PMP> cover -v- interlock

Actually, I have never heard an interlock described
in the way Gail described it.  In every case I am
aware of, an interlock (in this context) is used to:

1) stop the daisy wheel printer when the top cover
     is opened.
2) prevent you from moving the gear shift from
     park unless the brake is depressed.
3) etc.

When 1759 was developed, we discussed sensors
and switches in the context of an interlock so that
when the cartridge was missing from a laser printer,
an INTERLOCK would prevent the printer from being
used.  In this case there is no cover open yet the
desire is to signal a condition that prevents or
has stopped printing due to some mechanical
irregularity.

Don

To: pmp%pwg.org @ interlock.lexmark.com ("'PWG-pmp'") @ SMTP
cc:  (bcc: Don Wright)
From: bpenteco%boi.hp.com @ interlock.lexmark.com (Bob Pentecost) @ SMTP
Date: 03/07/97 04:49:47 PM
Subject: RE: PMP> cover -v- interlock

I prefer Gail's definition for interlock. Don's definition implies that
something dangerous to a person or the printer can happen and I don't think 
that's always the case.

Bob Pentecost
HP

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From:  Don Wright[SMTP:[email-masked]]
Sent:  Friday, March 07, 1997 2:49 PM
To:  Gail Songer
Cc:  pmp%pwg.org
Subject:  Re: PMP> cover -v- interlock

Gail songer said:
>A "door" is something that protects the mechanical insides of a device.

This one sounds good to me.

>An "interlock" connects two components of a device or two devices.  An
example
>of an interlock is mechanical latch on an optional sorter that connects
the
>base printer with the sorter.

I would define an interlock as:

A switch or sensor used to stop operation of the device due to the
opening of a door, cover or other component of the device in order
to prevent injury to a human or improper operation of the device.

Don

---

From: "Gail Songer" <[email-masked]>
Date: Wed, 12 Mar 1997 17:31:36 -0800

You know, this discussion really does not surprise me.  I had orignally polled
a bunch of the people here so that I could deside if I was just missing
something or if there really a potential for miss-understanding. Out of some 5
or 6 people that I asked, I got 5-6 answers.

Given that few people can agree on an interpretation of cover and interlock, it
would seem that we should have a definition for them. There does seem to be
some underlying understanding of "door" since most vendors only include sensors
to the outter shell of a printer in the cover table, and they are considered
"doors".

Perhaps we can narrow this down to "things" that are not covered elsewhere.
Hummm, Naw, this doesn't work because many "doors" can be visualized as being
associated with, a media path, or a tray or something.

Should be bring this up again the next time we meet?  I have companies waiting
for a good definition.

Gail

-- 

Gail Songer                                       Electronics For Imaging
[email-masked]                           2855 Campus Drive
(415) 286-7235                                    San Mateo, CA 94403