65C02 Halt and Resume

[Photoman]

Dr Jefyll wrote:

Photoman wrote:

Not going to be easy to break in anywhere other than the motor wires.

Yes, I was afraid of that. But the good news is, I was mistakenly assuming the motor was powered by the AC Mains -- 115V or whatever. Hence my remark about opto-couplers. Low voltage DC will be a lot easier to deal with -- we can easily concoct our own protection and locate it further downstream.

I see there's a reversing relay ( K3 ), which means we need to accommodate either polarity. Here's what I would suggest:

Screen Shot 2021-09-20 at 2.37.46 PM JL.png

At a guess, I'd say 2 watt zeners should be comfortably adequate, given the transient nature of the surge. The zener voltage needs to be well above the 15 or 30 volts seen in normal operation, so you could choose zeners rated at 40 or 50 volts, say. I wouldn't exactly call these freewheeling diodes, although they do serve to dissipate the energy.

Looking at the rest of the circuit, it seems as if IC7 is sensing and limiting motor current, as reflected by the voltage drop across R33. Further upstream, IC6 accepts a signal from pin 3 on the connector. Am I right in saying that's a 5V logic signal? Here a possible explanation. I suspect the current limit is there to protect your film and the gears in case of a jam-up. Limited current means limited torque. But the motor won't start reliably when the current limit is enforced; the motor needs extra current to get going from a stop. The logic signal gives it a temporary increase in the limit.

Edit: Hm, if indeed the current limit needs to be suspended for starting, then you may encounter difficulty when using the new manual switch. Opening the switch will surely stop the motor, but closing it again perhaps won't be enough for the motor to restart.

Thanks for the pics! -- I enjoyed those. Glad the flipflop circuit worked out.
-- Jeff

Hi Jeff,

Funny thing, every motor and pump belongs to a car! The jobo factory was down the road from a car plant so they just used parts that were cheap and plentiful.
Why reinvent the wheel when you don't have too. The rotation motor is a windshield wiper motor for an old BMW.
The lift motor is a passenger window lifter and the water bath pump is a coolant pump.
It does make second sourcing a little easier...sometimes. The motors are getting rarer these days in the US. The pump is easy to get even on amazon.

My luck would have it that in the pounds of diodes I have, the largest zener is a 27v 1 watt which wont work. Tons of rectifier, Schottky, signal and power...sadly only a handful of zeners.
I also have a lot of TVS diodes 1.5KE300A (300v ish breakdown) and some 1v5KE51CA (43v ish breakdown and bidirectional).
Would either of those TVS Diodes work in place of 2 watt zener?

Im not sure the current limiter or torque limiter works as intended. I can try to stall the motor but the only thing ill accomplish is breaking the nylon transfer gears.
They act as shear pins, whether by design or happy accident, they’ll break before the motor stalls, or tear up my hand.

If I do load the motor down with a much heavier drum filled with 1L of chemistry, it does bog down but it keeps going at the required speed.
The logic from pin 3 is 5v.

Thanks again!

[Dr Jefyll]

Quote:

Funny thing, every motor and pump belongs to a car!

Yes, I should've remembered that before assuming the drive motor ran on 115VAC!

Quote:

and some 1v5KE51CA (43v ish breakdown and bidirectional). Would either of those TVS Diodes work in place of 2 watt zener?

A 43 ish bidirectional TVS sounds good to me.

Quote:

Im not sure the current limiter or torque limiter works as intended.

Perhaps it's not working, or perhaps my hasty inferences regarding that circuit are incorrect. It might be helpful if you have any documentation that comments on the function of the 20K potentiometer, P1. Meanwhile, if the transfer gears aka shear pins seem satisfactory as torque limiters, then maybe you can just rely on that!

-- Jeff

[Photoman]

Dr Jefyll wrote:

Quote:

Funny thing, every motor and pump belongs to a car!

Yes, I should've remembered that before assuming the drive motor ran on 115VAC!

Quote:

and some 1v5KE51CA (43v ish breakdown and bidirectional). Would either of those TVS Diodes work in place of 2 watt zener?

A 43 ish bidirectional TVS sounds good to me.

Quote:

Im not sure the current limiter or torque limiter works as intended.

Perhaps it's not working, or perhaps my hasty inferences regarding that circuit are incorrect. It might be helpful if you have any documentation that comments on the function of the 20K potentiometer, P1. Meanwhile, if the transfer gears aka shear pins seem satisfactory as torque limiters, then maybe you can just rely on that!
-- Jeff

Hi Jeff,
Cool! I will make another perf board with some stak-ons (have a lot of board mount ones) and the TVS diodes.
Ill let you know how it ends up.

I have attached the only mention of the P1 pot in an old service manual for the older model.
The boards are close cousins. Some differences but it looks like the motor control section is identical.
The manual is definitely a poor translation from German to English. And the entire section that relates to the transformer board doesn’t exist.
This manual refers to the ATL 2 and 3 which are late 80s machines. There is no mention of it in the service manual that goes with my 2300.
I think you're right that it relates to the stall current but on my machine the way it acts is different.
When it starts, it does a half turn probably to find home, then a 3 or 4 full rotations. All of the ATL 2x00 ive seen act the same way.
I don't remember how the ATL 2 and 3s started up, long time ago.


I have a wonderful FujiMoto CP-51 paper processor made in Japan with AC motors and pumps (100v AC). Considering how leaky it can be, it’s a little terrifying that they chose AC instead of DC.
Though I see why, they needed a lot of consistent torque at a relatively low speed, also had to have an adjustable speed for various paper and chemistry types.
I think the most important part was space considerations. No room for a giant transformer and rectifiers. It is after all a tabletop processor (as in it takes up an entire tabletop).
There is an emergency drain in the bottom of the processor, though it really looks like an afterthought.
They also mounted the motors and connection blocks to the top of the case in the hope it wouldn't get wet.
Best laid plans as they say, when a hose leaks its always on the pressure side and can form a nice jet. Without fail its always aimed at something you don't want to get wet.
And do I have stories on this one. Had to do some major surgery on it, the PiD temp controllers died and I had to make a new one. It isn't pretty but it works!

[Dr Jefyll]

Photoman wrote:

I will make another perf board with some stak-ons (have a lot of board mount ones) and the TVS diodes.

Diodes? As your TVS diode is bidirectional it will serve to replace both of the zeners in the diagram I posted. So, you just need a single 43V TVS diode. (You could put 2 or more identical TVS's in parallel to increase the amount of energy that can safely be dissipated. I don't feel that's necessary. But if the idea appeals to you, go ahead!

Quote:

The manual is definitely a poor translation from German to English.

Hm, do you have access to the original German manual? There's a technically literate German speaker on this forum... Perhaps he could be coaxed to render an expert opinion on the matter in question!

-- Jeff

[Photoman]

Dr Jefyll wrote:

Photoman wrote:

I will make another perf board with some stak-ons (have a lot of board mount ones) and the TVS diodes.

Diodes? As your TVS diode is bidirectional it will serve to replace both of the zeners in the diagram I posted. So, you just need a single 43V TVS diode. (You could put 2 or more identical TVS's in parallel to increase the amount of energy that can safely be dissipated. I don't feel that's necessary. But if the idea appeals to you, go ahead!

Quote:

The manual is definitely a poor translation from German to English.

Hm, do you have access to the original German manual? There's a technically literate German speaker on this forum... Perhaps he could be coaxed to render an expert opinion on the matter in question!
-- Jeff

Hi Jeff,

It works! The switch stops and starts the motor no problem.
I did find out that the whatever state the heater was in (Relay on or off), stays when the processor is paused.
I don't think it will be a big issue, the water pump still runs so it shouldn’t go into thermal overload and the pause time wont be too long.

That’s the only manual I have ever seen. Im sure one exists in Germany but they only ever sent me the English translations.
Its not horrible and could be much worse.

Thanks again for all of your help!

[GARTHWILSON]

Have you looked into the details of TVSs? My understanding is that they suffer a little damage every time they absorb a transient to protect something else, and they can only do is so many times before they need replacement, unlike zener diodes which have no limit to life as long as they're not overheated.

[Photoman]

GARTHWILSON wrote:

Have you looked into the details of TVSs? My understanding is that they suffer a little damage every time they absorb a transient to protect something else, and they can only do is so many times before they need replacement, unlike zener diodes which have no limit to life as long as they're not overheated.

Thanks for pointing that out. It probably wont ever reach its lifespan in my use case.
But I do have the zeners ready for my next digikey order.

[Dr Jefyll]

I could be mistaken, but I thought it was MOVs that suffer a little damage every time they absorb a transient. Or maybe MOVs and TVSs both do.

-- Jeff

[fachat]

This looks like an interesting discussion... but I don't see it fitting the subject anymore, or is it? Maybe rename or extend the subject? Just so that I don't again click on it