Manual control mode on JLD 614?

[etrmedia]

Sorry if this was posted somewhere else... I searched, but could not find:

The instruction manual for the JLD 614 states the unit can be set to manual control. I do not see this option explained elsewhere in the manual, and cannot find it in any of the menus I've seen in the unit itself. How do I access this function?

[Tech_Marco]

What exactly do you want the controller to do?
When you said "manual control", pleae be more specific?

If you're asking how to turn On or Off of a heating element, then you don't need a temperature controller at all but a power switch. By using this controler, you can use the Up & Dn key, you can set whatever temperature you want to go, eitehr a heater or a cooler.

Marco

[etrmedia]

Thanks for the quick reply. I'm looking for a percentage output mode, with an upper temperature limit. Specifically, I'm looking to boil water, and have been told by a number of people that doing this in auto mode will cause problems.

[Tech_Marco]

Not sure why would it cause a trouble when using auto control system to boil water. Is it because it's keep boiling when temperature reach to 99~100'C and not stop? You application still unclear to me. You want to boil water but for how long of the boiling, a moment than stop , or keep boiling all time. Also, I'm not sure about the 'percentage' output. What do you mean of that?

Marco

[etrmedia]

I need to keep water boiling for about 90 minutes. I have read that since a boil is basically self-regulating, the heat loss during boil will interfere with the PID process, and the best way around that is to ramp up quickly to a boil, and then set an output percentage in manual mode (I believe this refers to a timed output percentage, where setting the controller to 60% would keep the SSR triggered for 60% of the time). I would love to be proven wrong on this, and will definitely try boiling in PID mode either way, just to get a data point.

Do you have any specific experience maintaing a boil in PID mode? I'd really like to hear if anyone has successfully done this.

Thanks again!

(By the way, this is for an electric home brewery)

[etrmedia]

...bump?

[richiem]

You can use the PID controller to keep water boiling by just making sure that the set value is somewhat higher than 100 deg. C, say 5 or 10 degrees -- but unfortunately, if the temp sensor is in the water, this means that the heat source will stay on all the time. So some experimentation is needed.

Using a ramp/soak type controller will let you apply plenty of heat to get the water boiling, then lower the heat a bit to keep it boiling. I'm guessing that this will require that you attach the temp sensor to the vessel and not put it into the water -- the vessel, especially near the contact point with the heat source, will be hotter than the water, which lets you vary the control temp to get what you want. The ramp/soak controller will let you then run the boil for the necessary time. You'll have to fiddle a lot with the initial set temp and the soak temp to get it to work, but then that's fun, yes?

[etrmedia]

... I suppose it is fun, yes.

So just to be clear, even though the JLD 614 page says it supports manual mode, it really doesn't? Would something like the JLD 634 be a better option for me? (which would be unfortunate since I already bought the 614)

By the way, thanks for the help so far with everything!

[richiem]

If by "manual mode" you mean can you manually adjust the SV on the fly, yes you can. But you can do that with a simple thermostat control. Presumably, you want some kind of unattended automatic operation. Your problem is the nature of boiling water itself -- it gets to the boiling point and then stays at essentially the same temperature, with any extra heat input above the boiling point being passed on through as steam -- this can be overcome by sealing the container, as in a pressure cooker, so that the water temp will actually increase above 212 F and give you the opportunity to measure -- and control -- the exact temperature of the water.

My question is this -- how critical is it to your process that the liquid actually boil? would a constant temp of 208 F work just as well as 212? If so, then the controller you have will work great.

[etrmedia]

What I'm looking for is a % output control. The JLD 634 offers this in a menu, and this is indicated by the illumination of the AT/M light on the front of the unit. The pictures on this website show the JLD 614 with this same label on the front of the unit, and the user manual for the unit says "Manual control is capable", but goes no further in its description.

Specifically, I'm using this for the boil section of my home brewery. I'm at about 5000 feet in elevation. To properly perform the brewing process, I need to maintain an aggressive (but not explosive) boil for between 60 and 90 minutes. The top of the boil kettle must be open.

[richiem]

While I don't fully grok what the manual is trying to tell me, I think you should use the JLD634 for your application -- I'm pretty sure it will do everything you are looking for.

I don't see any reference to manual operation of the 612/614 except for the trivial case of setting a SV and having the controller run the heater to that temp and then hold it.

Sorry I an't offer more help

[etrmedia]

Now, for a question of vanity:

Do all JLD 614 units have a red top/green bottom display and all JLD 634 units have a blue top/red bottom display? I'm using three of these units in one panel and would prefer some color coordination...

Thanks for everyone's time!