Over the last couple of weeks (just before and after New Year's), I worked with TT on a neat little project.
One test bay in Coolidge lab was being split into two. Two 100-amp feeds were needed along with a start/e-stop system outside each door, and an e-stop inside. We were given a couple of used NEMA enclosures and a 24VDC power supply. They'd also needed power outside the bays for 2 computers, a wireless router for each system (to connect to the bay), among other things.
The almost-finished cabinet, "left" bay.
A simple little design I'd added to the new radiation-protected test bay. It uses mains power for a duplex receptacle (mounted on the left side, behind the door from PANEL 1 (Marked Panel N for some reason) off a 15 amp breaker. Not ideal, but I'm not running the job. They wanted the power to the external red warning lights to be "ON" whenever it is possible to shoot x-rays, also only have the ability to do this with the door physically closed.
Enter BANNER.
This device runs off +24v and can use up to 4 fiber channels. Simply run 2 lengths of fiber to a 4"x4" box, mount the fiber ends in a transmit and receive end in the box, then mount another box on the door, with
the fiber "jumper" in the box. With the door closed, the BANNER device emits a beam from E1, to the
transmit coupler, through the "jumper" in the door box, back through the receive coupler, then back to the
BANNER device at R1.
With this, I added the output control (pin 17) to control a relay (pictured lower right). This controls both the red door warning light and another "fail-if-opened" circuit from the PDU.
Still not as fail-safe as I'd like it, but that's how the others are done.
A little mishap today; since I was bitched at by a journeyman for actually taking the time to draw out a
blueprint for a complex project I had engineered recently (and gotten a company EXPERTISE award for), I didn't want to waste ANY company time by doing something so "trivial". You know, so if anything goes wrong, or the FDA would like to document our process, they wouldnt have to GUESS. So, it's been two weeks since I've seen this project (the BANNER controls just came in today), so I'd forgotten exactly how I'd wired it, and confused the 110v out to the light with the 110v in to the receptacle. "Oh, this needs a jumper in the terminal block". I'd put one in and accidentally shorted something. Hmm? Was it wired wrong? Nope, I'd just grazed the jumper on the neutral terminal block; they mount on the top and screw down, facing you. They are rather close. I'd 'flipped' the jumper bar end to the other side to keep it a few mm away from the neutral, but must have grazed it anyways.
Still waiting for said journeyman to deliver a set of insulated screwdrivers. A set of terminal block drivers were delivered second-hand instead last year. Funny, they don't say INSULATED anywhere on them.
When the Apprenticeship Committee asked "You need any tools?" I asked for insulated screwdrivers.
"You arent supposed to be working on live stuff!"
"Everything we do is live, or next to something live"
"But still, you shouldn't"
"I'm asking for them to be used as my PRIMARY tools, because you never KNOW if something is live or could BECOME live"
They must not like it when I use logic and assertiveness, as four years later, I still dont have any tat I did not buy.
Here's another one;
We are to not trust our "pocket voltage detectors", but instead use our voltmeters. I always use both of them.
I'd asked;
"Because of FDA compliance, we need calibrated voltmeters, can we get the Apprentices voltmeters on the cal(ibration) list?"
"You arent supposed to use them on production things, use your journeyman's meter"
"What about if I'm supposed to check for voltage, and my meter doesn't work. That could be fatal. How will I know if it's 'hot' at all?"
"Use your pocket ticker."
This is the Union/Apprenticeship Committee saying this, not the company. You'd think it was being paid for by the Apprenticeship Committee members, the way they fight us on the most logical things.
I'm ranting again. That's another topic.
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