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Re: PID Thermo controller

Posted: Sat Jun 01, 2013 6:18 am
by loetz
Thierry wrote:
This functionallity should be named "f..k your boss" but here it's just damed "Digital Filtering", "dF" in Short. Just put that value to 0.
I can attest that this works! Thanks for the help Thierry! I suggest that everyone else checks to make sure that they have the dF set to 0 instead of 1. This option is in the second settings menu. It will stop the PID from lying to you about the actual PV temperature.

Now to get it to stop overshooting the SV...

Thanks again Thierry!

Re: PID Thermo controller

Posted: Sat Jul 20, 2013 9:36 am
by varocketry
I read the Apr 23rd post by mnphyscist and would appreciate some KNOWLEDGEABLE PERSON's counsel on the proper FUSE to buy. I've been trying to research to know exactly what I need.

I have the RKC C100 PID discussed in this thread and a 40amp SSR to control a 5500w 240vac heater element.

This diagram from the site is roughly what I'm trying to build, it shows a fuse on one of the 240vac leads to the SSR from the contactor.

Image ... iagram.JPG <larger image>

What type of fuse should this be?


Re: PID Thermo controller

Posted: Sun Aug 04, 2013 8:20 am
by RocketMan
varocketry, the general rule of thumb for fuses in a heating application is to choose a value equal to the nominal heater current, plus 25% for initial power-on surge.
For example, if the heater normally draws 10 amps of current, choose a 12.5 amp fuse to protect the circuit, or the nearest higher standard value if a 12.5 amp unit does not exist in the style of fuse selected.
Be sure to select a fuse holder that is rated above the amount of current, including the surge current, and the voltage of the circuit. In this case I would choose a 600VAC rated fuse holder. That is a good standard value for fuse holders. A 250VAC rated fuse holder is too close to the nominal voltage of the circuit.
The current rating of the fuse holder depends on what the heater is rated, plus initial surge. Use a fuse holder rated for higher current than those two combined values.
One other thing to consider is the location of the fuse. Were it me, I would locate the fuse ahead of the contactor in order to protect the entire circuit. Locating the fuse downstream of the contactor is not good practice, as it cannot protect the contactor and related wiring in the event something fails to a short or ground.

Judging by your user name, you fly rockets. Low power, mid- or high power, or all of the above?


Re: PID Thermo controller

Posted: Sat Jan 11, 2014 1:03 am
by mikec
I have used several of these with success C100 C700 and C900, I have never needed to use the alarm function before, but now I need it to function, after trying all the options I still cannot get it to function. I wish to set a target temp and have the alarm activate when it reaches it. Can anyone help in laymans terms?


Re: PID Thermo controller

Posted: Wed Feb 05, 2014 5:16 am
by molove
mikec wrote: I wish to set a target temp and have the alarm activate when it reaches it. Can anyone help in laymans terms?

I have a C100 and there are a few different alarm modes, the default for mine is "Deviation high alarm" which means the number set by AL1 is for the number of ºC above the SV value that PV must reach before the alarm will activate ie Alarm will activate when PV=SV+AL1 eg if you set AL1 to 0 the alarm will activate at the temperature set by SV.

You can change the alarm mode in the Initial Setup menu (Cod=0000) by navigating to SL4. If you wish to be able to set a temperature above which the alarm will activate in AL1 you need to set the alarm mode in SL4 to be "Process high alarm" which on my C100 is SL4 = 0011

You may also wish to alter the AH1 value in the Initial Setup menu. This is the Alarm hysteresis ie the difference in temperature that the alarm activates and deactivates.
AL1 = 0050
AH1 = 0002

when PV reaches 50ºC the alarm will activate and stay activated until PV drops to 48ºC (ie AL1-AH1)

Hope that helped


Re: PID Thermo controller

Posted: Wed Feb 05, 2014 6:06 am
by molove
Anyone any idea about this?

I have a REX C100 which I am using as a temperature controller, mainly to be able to use a slow cooker for sous vide. I am using a K type thermocouple and the C100 is limited to ºC, so at the moment, the accuracy of the temperatures I can set or measure is limited to 1ºC.

I have tried to use the autotune feature of the C100 but the changes in temperature happen too slowly for autotune to work, and it stops trying to autotune when PV reaches SV, and sets P (proportional band) to 0. The manuals I have read state temp needs to change by 1ºC or more in a minute for autotune to work.

As I understand it, if I were to use a PT100 thermocouple, I would be able to measure and set temperatures with an accuracy 1/10th of a ºC.
Does anyone know if using a PT100 would make any difference to the rate of temperature change needed for the autotune function work? ie instead of needing a change of 1ºC/min, would it only need 0.1ºC/minute?

Has anyone had any success using the autotune feature whilst controlling a slow cooker?

Or, does anyone have any tips for how I would go about tuning manually?



Re: PID Thermo controller

Posted: Tue Feb 11, 2014 5:42 am
by Brucifer
Greetings, I have found a place for information. Thanks, Yes, I did not write down any factory setting. I bought an EB copy of a REX C100F (PID,45watt SSD, K thermal). It says plain as day 220vac on the case. That is euro elect, right? No problem another project gone amuck. Add it to the list. research dummy research.

OK I would like to learn some elect.

1.I would prefer to replace the transformer in the case to supply the needed VAC from 120 vac-us (60hertz). Is that trans. available?

2.I have found a Halogen trans that will make me 12vac. Do I break the 12vac down to 10vac with a resistor?

Isn't the internet neat!! HAVENICEDAY

Re: PID Thermo controller

Posted: Sun Oct 12, 2014 3:50 am
by yello
I bought a Rex C100, since the price was below $6.00 I presume it's a copy. Mine is with output for SSR, connected to an SSR. I played a bit with it out of the box and have some problems. Sensor is the common K type.

SV = 185°C
Heater: 2 PTC heater (220V/20W/270°C)

Problem is that the SV totally overshots. When I connect power then I can see the SSR will go on and off. ON for a second, then OFF for a few Seconds. The PTC heater act very fast. But here is the issue: even after I hit PV 185°C the SSR still gets power with the same pattern and eventually the temperature goes up over 200°C (I have seen 230°C!).

What I totally don't get is why the SSR still gets power from time to time if the temperature is already above 185°C?

Since this is damaging my test object I don't want to make too many tests at this point. I went though the many manuals only. They explain the key strokes, but not really what to use when.

I hope somebody here can show me the light.

Re: PID Thermo controller

Posted: Sun Oct 19, 2014 7:19 am
by RocketMan

Look over your documentation for the "Auto-tune" function. Use "Auto-tune" to automatically set the controller's PID tuning parameters and it should control your system temperatures much closer to setpoint (SV).
"Auto-tune" may be called something else in your documentation. If it exists in your controller, you should be able to figure out their name for it and make use of it. Using the auto-tune function is much easier than trying to tune the PIDs in one of these controllers manually. I used to manually tune temperature controllers in semiconductor growth furnaces years ago before auto-tune became a common feature. Manual tuning can be a real pain in the posterior.

Re: PID Thermo controller

Posted: Mon Dec 15, 2014 5:20 pm
by maxx123
Hello have a c100 with internal relay removed ,connected to a ssr been trying to program , simple configuation heat up to 75 c low 65c . it seemed to over heat to 175 c dangerous

unit china o to 400C K

all i need is proper programing # so i do not cause any dangerous results

very concerned odd temp controller , seems one can get calibration for video but for this c100 unstable