Questions to ask before buying a PID

[bbogue1]

Questions to ask before buying a PID
Does it come with instructions for this PID?
Not only on boot up but in the menus Does it display two rows of four zeros (0000/0000) as needed?
Will it allow changing the LCK setting,
Will it allow the P setting to be set to 0000,
Will it allow access to and changes to the COD and the COD1 menus?
When changes are made is the setting saved permanently?
Do the instructions explain how to display 1/10 and 1/100 of a degree?
Do the instructions explain how to adjust the number of degrees variance (over or under temperature) the
PID will allow?
Is this PID designed to work with an SSR?

[Mike W1]

Lots of luck on the above! The most commonly mentioned that I've seen are Auber, Mypin and Rex. I've had all 3 and the only one with instructions a newby could follow was the Auber. The Mypin has a decent manual available written by a former soul on this forum that isn't too bad. The other instructions available (at least what ever I could find) on the web are pretty much worthless to us less knowledgeable beings. Have a bit of experience with all 3 of them at least for our purposes on here. Those little PID units actually will do more than we have requirements for IF one thoroughly understands them.

The big thing I see is not everyone knows to look for a SSR output on the PID. Anything can probably be modified to work but why bother when the right stuff is out there. The Rex comes to mind as a problem child. There's knockoffs of them called Beirme (or something close to that) when what you need is the RKC made in Japan and not China. Even a huge per cent of the RKC's on ebay are Relay output and not SSR. Gotta read the specs folks.

I've had all 3 brands and they are all somewhat similar to set up but there are differences in how it's accomplished. I don't see any need to read to 1/10 or 1/100 of a degree for our needs. Likewise the Rex only reading in Celsius has not proved to be ANY handicap to me as making a little chart up comparing C to F took care of that.

In any of the 3 all that was realistically pertinent was to set the desired temperature and turn on the autotune feature and let the PID do it's job and set the P, I and D values. It helps to be able to scroll thru the parameters but there aren't normally very many of those that have to be changed. And in any but the Auber you'd better know exactly what you're trying to accomplish or the instructions are pretty lacking. Those Chinese/English translations leave much to be desired plus you can't ask support for help as it apparently doesn't exist EXCEPT with the Auber folks.

After awhile one becomes as familiar with a unit as we are likely to become. In the end though all 3 mentioned will do a good job for us IF we buy the right model. One thing I have decided is there's probably some quality differences between the TC's I got from Auber and the cheap ones I got on ebay. At least so far I've not had to replace a Auber TC but then they costs 6-8 times as much as on ebay. FWIW

[JonB_in_Glencoe]

As many times as PID models has come up in conversation here, I seem to be the lonely one, who chose the JLD-612.

I chose it specifically for the detailed manual, while it's not simplified for a non-techy type, it isn't a Chinese-English Mish-mash. Another great thing about this manual, is that last section "7. Device Application Example " the example they use is basically our usage for a High temperature furnace control.
Lastly, it's available from a large reputable US source for a pretty good price.

Manual PDF
http://fhupiora.fhupiora.home.pl/JLD612Manual.pdf

[dikman]

Mike pretty well sums it up - if you try asking all those questions of a seller I reckon you'll have a long wait for an answer (assuming they even know the answers). I have one, the name escapes me at the moment, that I bought off ebay. It's dearer than the Rex and is actually a very good unit. The instructions weren't bad, but like most require some working out and reading on the 'net to understand what they're talking about. Fortunately, as Mike also said, most of what they can do is irrelevant for our needs. As are most of those questions.

One thing, however, is that I still see some sold as packages with SSR and probe, but they're actually relay output PIDs! It's no big deal to modify them, as long as you know what you're doing.

[Mike W1]

As dikman said a lot of those packages have Relay Output. My looks on ebay indicated most of those packages were Relay. Personally I wasn't interested in modifying a inexpensive unit and I have a "bit" of electronics experience (probably have forgotten most of it) working on $100K tape recorders in my army days and a splicer with a Telco hooking up a lot of expensive gear. After working on some of that quality stuff I found it quite difficult to solder on a cheap circuit board for one thing. Could only imagine how much fun it'd be to in a $12 item.

Actually pulled a pdf of the JDL-612 way back. At this point I'd say the manual's useable but obviously still a translated document that leaves something to be desired. However it's far better than the Mypin and Rex manuals.

[dikman]

C'mon, Mike, you know you an do it . Open the case, desolder the relay and solder in two wire links. I have the utmost faith in your abilities.

[Mike W1]

I probably could but after some advice posted on here I managed to buy the proper models for all 4 units I built.