Fuji controller mishap & question

[Mike Firth]

I bought a Fuji PXR controller when my old Love unit died.
Wired it carefully, mounted it and tested it for reasonableness.
Only change - upper limit from 400C default to 800C
First run - fuse some plate glass. Use the controller to simply hold the final temp 790C (1450F).
Hmmm! 718C indicated. It's taking quite a while to get to temp. Lets take a look.
WHOA WHITE HEAT PULL PLUGS
Glass is molten with bubbles. Are the molds ruined.
Plug the the thermocouple into a meter - 890C!!!!!!!!!!!!!!
Vent the kiln to drop temp. Compare second temp on controlelr and meter 175C difference.
Begin comtemplating cause of disaster.
After a night of thought, wondered if among all those parameters I wasn't using, there was one for the Type of the Thermocouple, just like the one I noticed for F/C even though it has C printed on the controller face. I had ordered K-type.
Hunt, hunt, hunt. YUP - Here is a setting for K, J, T, etc.
Set to J. Change it to K. Do a test run. Okay.

So here is my question - when I start using some of the features, like ramping up or down to control heating and annealing, does anyone know from experience of parameters that can cause a disaster (or problems) if they are not set - like an upper limit on program temp that is separate from regular set point temp or some other hidden switch on the third menu that affects the second menu?

[Brian Gingras]

" So here is my question - when I start using some of the features, like ramping up or down to control heating and annealing, does anyone know from experience of parameters that can cause a disaster (or problems) if they are not set - like an upper limit on program temp that is separate from regular set point temp or some other hidden switch on the third menu that affects the second menu?"

Well in hind site, check every parameter...go through the whole thing understand every setting, verify that they are correct, then use the controller.

Ok, it wasn't the most specific answer, but why not completely understand the tools before you start to use them?

[Drew Fritts]

Mike,

You found the most critical one, unfortunately. The other thing to be aware of is, if you have all your parameters set and your ramp and soak program entered and THEN go and change the max temperature setting, it will modify your programmed ramp and soak temperatures proportionately.

I'd recommend adjusting the output cycle time (assuming you have the relay/SSR driver and not the built-in relay). If you're using a non-solid state relay or contactor, it needs to be 30 seconds or more. The longer you set it for, the less wear on your output device, but the longer it will take to recover temperature, too. If you're driving a solid state relay it can be as low as 1 second, but it doesn't need to be for annealing or fusing purposes.

Another thing to be aware of is that if you activate all of the programming steps, you don't necessarily have to use them all. If you leave the ramp and soak steps set to zero, that step will be skipped. This comes in very handy, for example, when you want to ramp up and hold for an undetermined amount of time. When it hits the "END" state in the program, the controller will hold at the last temperature it actually executed. So, if your first step was the ramp up to annealing temperature, and all the rest of the steps have zero ramp and soak times, it will sit at your annealing temperature until you tell it to do something else. I can give you more details on how to use this feature if you want. Just Email me.

On the third menu you can turn on and off certain features using the hex dsp parameter masks, such as alarms (which I don't use so I turn them off). If you turn a feature off on the third menu, you won't see the prompt for it on the first or second menu.

Lastly, when you're running a program, let it get up to temperature and then turn on the auto-tune feature. The light will blink for a little while and then it will go off. This process sets all of your proportional control numbers automatically. Note: This only needs to be done once to set up the controller, but can be done again if you drastically change the type of program you're running.

If you need help figuring out the dsp settings or have other questions you can contact me directly: drew()frittsartglass()com.

Drew <+><

[Garner Britt]

Mike,

yes, the t-couple setting is the one that nearly burned me too. Fortunately, I noticed at room temp.

Like has been said, try to understand as much of the parameters as possible then mask them off so you don't have to see them or have the opportunity to get lost in some sub menu and make some accidental change.

These things do so much in such a small package it can be overwhelming

On another note, I just bought an Omega CN7500 (8 programs x 8steps ea, $100 new from Omega) It has a link function to link two programs to make 16 steps. On my first firing, I wondered why they damn thing was ramping up again after dropping, turns out the link function default is not off but the first program, Seems crazy to me that default is not off....

garner

[Matt Bezark]

and some controllers (like my watlow 8cls) will automatically go back to the "hold" state or first step in a ramp cycle when the program is finished unless you tell them to do something other than that.

i solved that by always adding a 999 hour segment at whatever temp the final ramp stage hits, such as 0 for cool down or final up temp if i'm ramping up my electric furnace.

matt.

[Mike Firth]

Thanks for the answers. I've been off the board for over a month and just got back. I've been wading through all the settings trying to figure out what they do even if I am pretty sure I will never use them.
My wife reads the entire manual for programs and computers and knitting and then knows stuff that nobody else knows. I read just enough to get started and plunge right it.

[Hugh Jenkins]

The Mode setting for the end of the program can be a little confusing. It can be set to go "off" in which case the "setpoint" control takes over, or to repeat the program, in which case you are in and endless loop, or go to "standby" which is what you really want, since both Program and setpoint are inactive. It will wait for you to tell it the next step. I think it is Mode 4 that you want for this but check the setting table to be sure.