I have just re-commissioned an electroplating/anodising machine I built almost 20 years ago.
Incorporated in this equipment is a REX temperature controller manufactured by an American/Japanese firm RKC.*
Its correct description is Single loop MCU-based Direct Digital Controller.
At some stage at least 12 years ago, I had an accidental corrosive liquid spill which I cleaned-up as best as I could immediately after it happened.
For plating or anodising with different kinds of electrolytes including electrolytically stripping gold or nickel etc from metal objects, different current feeds, temperatures, ph and so are required and the REX controller's job is to pulse ac current to a heating element to a pre-set value on the controller and thereafter maintain the set value (SV).
Anyway, after the accident, I deemed the wiring, the controller and the heater unsafe as it tripped the mains so over the last few years, I only used the machine's air pump when plating or anodising metals.
During the past few days, I had a chance to renew some wiring. I made new brass fittings for the dc current feed and a couple of other improvements to the point where I thought the equipment would be safe to operate with all its functions again.
First, I got the heating element to work again after all these years and then I immersed the thermocouple into a liter of water which again tripped the mains but there was enough time to see the controller's LCD displays were still functioning and still set on the appropriate temperature for heating nickel plating electrolyte which is 67degrees C.
I realised years ago that the thermocouple had to be protected against the nasty corrosive chemicals I work with so I pushed a tight-fitting plastic sleeve over the thermocouple and sealed the end with a soldering iron.
Yesterday, I cut off the sleeve and saw 5 tiny pinholes eaten into the thermocouple but could not determine if these holes were right through the t/couple's jacket but decided to try something else.
I carefully cleaned the thermocouple, warmed it with a hairdryer to expel possible moisture ingression if any and then coated it with Araldite.
Well today I tried the equipment at various temperatures and everything works just fine, no more mains tripping.
The controller has a 6-page programming manual and also incorporates 'auto learning' of the properties of whatever heating element is connected to it.
So, over a near 20 year period of being disconnected, it 'remembered' all its original setting and programming.
I think this is quite amazing and wonder how this was possible - I haven't looked inside the device but there must be capacitors storing current inside which protected and retained its settings made all these years ago.
mafioso
*) No affiliation whatsoever
Incorporated in this equipment is a REX temperature controller manufactured by an American/Japanese firm RKC.*
Its correct description is Single loop MCU-based Direct Digital Controller.
At some stage at least 12 years ago, I had an accidental corrosive liquid spill which I cleaned-up as best as I could immediately after it happened.
For plating or anodising with different kinds of electrolytes including electrolytically stripping gold or nickel etc from metal objects, different current feeds, temperatures, ph and so are required and the REX controller's job is to pulse ac current to a heating element to a pre-set value on the controller and thereafter maintain the set value (SV).
Anyway, after the accident, I deemed the wiring, the controller and the heater unsafe as it tripped the mains so over the last few years, I only used the machine's air pump when plating or anodising metals.
During the past few days, I had a chance to renew some wiring. I made new brass fittings for the dc current feed and a couple of other improvements to the point where I thought the equipment would be safe to operate with all its functions again.
First, I got the heating element to work again after all these years and then I immersed the thermocouple into a liter of water which again tripped the mains but there was enough time to see the controller's LCD displays were still functioning and still set on the appropriate temperature for heating nickel plating electrolyte which is 67degrees C.
I realised years ago that the thermocouple had to be protected against the nasty corrosive chemicals I work with so I pushed a tight-fitting plastic sleeve over the thermocouple and sealed the end with a soldering iron.
Yesterday, I cut off the sleeve and saw 5 tiny pinholes eaten into the thermocouple but could not determine if these holes were right through the t/couple's jacket but decided to try something else.
I carefully cleaned the thermocouple, warmed it with a hairdryer to expel possible moisture ingression if any and then coated it with Araldite.
Well today I tried the equipment at various temperatures and everything works just fine, no more mains tripping.
The controller has a 6-page programming manual and also incorporates 'auto learning' of the properties of whatever heating element is connected to it.
So, over a near 20 year period of being disconnected, it 'remembered' all its original setting and programming.
I think this is quite amazing and wonder how this was possible - I haven't looked inside the device but there must be capacitors storing current inside which protected and retained its settings made all these years ago.
mafioso
*) No affiliation whatsoever
