Thank you all for the supportive comments. And thanks for moving my off-topic comments to a new thread. I apologize for inflicting on you an update on my health problems. The move to Florida was more stressful than I had anticipated, but ultimately was in the best interest of my health... well, so far, anyway. I've had to give up a lot of "bad habits" accumulated over the years just to stay alive this long... smoking tobacco, drinking alcohol, consumption of sweets... all to excess of course. Giving up vaping was the easiest: my wife hid the vaping apparatus after my heart surgery!
The problem with living is no one survives it. At one time (early in my youth) I had the notion that technology might indefinitely extend some semblance of life, but that was (and still remains) in the realm of science fiction. It turns out that even if I had done everything right for the past seventy-something years, there is a built-in self-destruct mechanism for every cell in my body:
telomere deterioration. This is probably Nature's Way of avoiding over-population of the planet, while allowing evolution to proceed, but it sounds like a rather poor design to me, even if done with good intent. Maybe the bio-tech weenies will figure out a way to fix it.
Oh, well... my father was more than eighty years old when he asked me how long a person was supposed to live. He had survived two open-heart surgeries by then, was fighting to survive lung cancer, and was legally blind from
macular degeneration in both eyes. His favorite things, tending to his vegetable garden and small backyard fruit-tree orchard and visiting his beloved and nearby Rocky Mountains were now impossible for him. My reply to my father was to "live as long as you want." Some time later, he refused to continue to accept an experimental anti-cancer drug treatment that the VA hospital said was keeping his lung cancer in remission. He died quietly and alone shortly afterwards. A few years later my mom tripped over a toolbox and fell but never regained full consciousness after a "successful" operation. She died, also in her eighty's, in a nursing home in Georgia, more or less in a permanent vegetative state, kept alive by a feeding tube surgically inserted in her stomach. My brother died last year in Sarasota, FL, while living with my daughter and her husband, after a decades-long battle with cancer, not quite reaching the age of seventy. Realistically, with my former reckless life-style, I never expected to survive to reach the 21st Century... yet here I am. I do plan to go out kicking, screaming, and fighting all the way if possible, but who knows? In the meantime, I continue to do what I do and live one day at a time.
That's a handy bit of electronics kit you have implanted!
Yes, it literally saved my life... several times, apparently. Battery inside is NOT externally rechargeable but is supposed to last another eight or nine years. Coin toss whether it or I expire first.
if you would like a better title give me one and I will edit it
Nah, that one is "vague and hard-hitting" enough, a phrase we used to use to describe technical proposals we sent to the Government, seeking taxpayer's money.
The wiring of those panels is fantastic...
Thank you. I wanted it to be maintainable, since I would probably be the one maintaining it. One of the C&K toggle switches mechanically failed several years ago and I did not replace it. The wiring is tight around the switches, so replacing one would not be easy. Since there were those three "extra" switches not connected to vacuum valves, I simply re-purposed one of them to replace the defective switch and then ignored the defective switch.
Each of those white wires is identified with a laser-printed paper label encased in transparent shrink tubing. Years ago, while working as an electronics technician for UDRI, I had the task of making wiring harnesses under a government contract. I was supplied with a spiffy little wire marking machine that repeatedly imprinted entire lengths of wire with a specific wire number. I don't remember exactly how that was accomplished, but the idea stuck in my head that it was a pretty nifty thing to do. So when this project came up thirty years later, I decided to label each end of each wire with something useful to identify its function. Fortunately affordable desk-top laser printers had come into being by then, so it was no trouble to print up batches of labels created in Microsoft Word and cut them out with a razor blade to wrap around the wires.
I got carried away, a little, with the initial design of the switch panel. There are ten DPDT center-off toggle switches used to control solenoid-operated electro-pneumatic high-vacuum valves... seven switches for the valves and three more for things like the heaters on the oil-diffusion pumps and a radiation warning light above the entrance to the accelerator lab. Each switch has three positions. The center OFF and fully up ON positions turn a valve solenoid off or on for manual operation. The third fully down REMOTE position was intended for automatic sequencing of the valves under control of the Allen-Bradley PLC.
However, I am not much of a believer in allowing a computer to have full control of anything without putting a human somewhere in the control loop. So I engineered in the manual mode of valve control, "just in case" it might be needed for troubleshooting or to override the PLC. To that end, the initial (and only) programming of the PLC was a routine to examine the toggle switch positions and then energize or de-energize the appropriate 120V AC output, connected to the top ten terminals on the left side of TB6 (the leftmost barrier terminal strip on the panel in the center of the picture). These ten outputs, on the right side of TB6, are obviously unconnected in the photo since those connections go to the external valve solenoids, or heater contactors and such.
One of the center poles of each toggle switch provides the left-side connections to TB6, with 115 V AC either being supplied through its REMOTE contact, via one of the two 6-output AC output modules in slots five and six, or directly from 115 V AC applied through the ON contact. In both cases, the 115 V AC is fused and switched by a fail-safe interlock relay on the interlock panel partially visible on the right side of the photo.
BTW, for those of you who are counting, Slot 0 is occupied by the SLC 5/03 CPU module. Slot 1 is occupied by a 4-channel thermocouple digitization module, Slots 2 and 3 are occupied by 16-channel DC input modules, and Slot 4 is occupied by a 16-channel DC output module. The DC inputs are provided by other poles on the other half of the toggle switches to allow the PLC software to determine the switch state, i.e., REMOTE, OFF, or ON.
Having pretty much decided how I wanted this beast to behave I went ahead and wired it as shown before tackling the programming. I had never written a PLC logic-ladder program before, but had performed several dozen diode-relay logic designs in the 1960s and 1970s. How hard could it be?
The A-B PLC mounts on a removable panel with its own barrier terminal strips located inside a NEMA enclosure mounted below the interlock relay panel, so it was easy to remove remove both panels without disconnecting any wires connecting to the PLC. The interlock panel was retro-fitted to an existing, much modified, 120 VAC interlock system that I inherited with the particle accelerator, so there were some wires that had to be temporarily removed there. Basically, all the interlocks are normally open switches, wired in series and located all over the accelerator in various places. If an interlock is "satisfied" the switch contacts close, and when all switches are closed the machine is ready to operate. I added contacts from a three-phase "power good" module, seen protruding from the back of the interlock panel, to the interlock chain and modified the interlock relay to be "fail safe" and thus require a manual reset operation to restore operation.
To "seamlessly" transfer from manual to remote operation, I programmed the PLC to determine
and maintain the previous state of the toggle switch when it is moved from either the OFF position or the ON position to the REMOTE position. If the switch was initially ON, then moving it quickly through OFF to REMOTE resulted in the switched output remaining ON. If the switch was initially OFF, then moving it to REMOTE resulted in the switched output remaining OFF. All of this essentially required only the ability to recognize, and remember, when a change-in-state of the switch occurred and then act accordingly. My original intent was to design a state machine in software that would sequence the vacuum control valves in the proper sequence to automatically pump down the accelerator while warming up two oil-diffusion pumps.
By the time the project reached this point, I had demonstrated the "nifty" toggle switch action, but we had run out of time and money for any further "improvements," unless performed gratis by me on my own time. Okay, I thought, so it isn't a fully automagical pump-down vacuum valve sequencer like I planned. It doesn't monitor the oil temperature of the oil-diffusion pumps. It doesn't monitor the water temperature of the chillers used to cool the diffusion pumps and the mass-selection electromagnet. It doesn't automatically open the high-vacuum valves when the diffusion pumps have reached operating pressure. Yada, yada, yada. What it does do is sense whether there has been a power failure of the incoming three-phase lines and, in response to said power failure, close
all the vacuum valves until an operator presses a RESET switch. Mission accomplished. More or less. We had a few power failures over the next ten years, but the machine always shut down and the vacuum valves closed, milliseconds before hot diffusion pump fluid could be injected into the accelerator columns through failure of the fore-line mechanical vacuum pumps. This avoided an expensive and time-consuming procedure to clean the accelerator columns, which was the whole reason for doing the project in the first place. This was my "baptism by fire" after less than two years on the job, circa 1998.
Certainly I was remiss in not changing the Li-Ion battery myself, but I had informed my "replacement" of its imminent demise and suggested he take care of it. I also mentioned it to my supervisor, who ignored it. Since no one else was interested, and I could see the writing on the wall (no business for the accelerator), I ignored it too. Today, with flash memory, it would not be a problem.
Two years after my "retirement" on December 31, 2014, I received word that the particle accelerator wasn't working, and was asked if I could come "look at it?" I didn't respond right away, but since we had to return to Dayton anyway, I decided to stop by and see what the problem was. Sure enough, the A-B PLC program was trashed. There were other problems as well, because it should have been possible to manually sequence the vacuum valves to pump down the accelerator, but I didn't have time to farkle with it. So I suggested they send the control panels to Venice for me to work on them here.
It took awhile after I received "the package" shown in the photograph to get to the point where I could begin programming and testing it again. I found some hand-written diagrams (my personal notes made during its construction) of how it is was wired, but part of the job was to transfer this information to a "pretty print" PDF file so someone else could use the documentation for maintenance and troubleshooting.
I only just recently, with some trepidation (I don't have a lot of replacement fuses on hand), connected 120 V AC power to the interlock panel to power up a 15 V DC power supply there that energizes the switch panel lamps and provides high-level logic signals (through the toggle switches) to the DC Input modules. It was quite satisfying to see the LED bit-status indicators on the input modules responding properly to toggle switch positions! Onward to replacing the corrupted ladder-logic program!
NEWS FLASH!
I learned yesterday that the Tandetron tandem particle accelerator will be disassembled and moved to Anaheim, CA, gratis with no cost to UES, Inc. Maybe the new owners could use my help and advice on how this move can be accomplished, and the re-located particle accelerator brought back to life... there are a lot of nuances involved in handling sulfur hexafluoride and cesium metal, not to mention the beam-line components that require "special handling" and replacement "O"-ring gaskets once the vacuum joints are opened... I don't think the "tank" can be moved without separating it into three sections for transport, but these Nimrods are claiming they can accomplish the move in one week. Yeah, gimme a Sawsall. a sledge hammer. and a muscular crew with low foreheads and I'll have that sucka outa there in pieces in one week! Good luck putting Humpty Dumpty back together again.
IIRC, it took the folks at Oak Ridge National Laboratory more than a month to move their de-comissioned Tandetron to a local college in Huntsville, AL. I guess we'll just have to "wait and see" what happens. I am probably not going to get paid for any of the work I have done, or the expenses incurred so far... <sigh>
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