Hi to all.
Since my electric oven thermal-switch is broken I'm thinking to replace it with this PID temperature controller.
I looked for one that could regulate temp and time but couldn't find it.
Please help me to choose the right type of sensor.
Which is better big one or small one?
which is the best position to place the sensor, number 1, 2 or 3 (see picture)?

 

What are you using the oven for? From your diagram it appears to have a fan for circulating the air?

 

The type/size and position of the thermocouple probably won’t make that much difference to the temperature control of the oven. More important is the mounting arrangement required, the smaller appears to incorporate an M6 thread which might make for an easy mount into a suitably threaded hole, or a hole and fixing nut. The larger/longer type thermocouples are normally held in place using spring jubilee type clips.

 

What are you using the oven for? From your diagram it appears to have a fan for circulating the air?

My mom use it to cook bread and cake. Yes it have one fan for air circulation.

@Hymie
I just want to choose the best sensor no matter how it's mounted. Are you sure that the sensor geometry is not changing the performance?

 

My mom use it to cook bread and cake. Yes it have one fan for air circulation.

@Hymie
I just want to choose the best sensor no matter how it's mounted. Are you sure that the sensor geometry is not changing the performance?

In that case, I doubt it matters much. As long as there is good air circulation, I would position the sensor away from the heating element. Personally towards the middle of the stove near the top.

 

The temperature controller you linked to, a REX-C100 includes a Type K thermocouple as the sensor. You choose a thermocouple sensor depending on your specific application. Your link also includes a 40 Amp SSR. The controller should work with any Type K thermocouple. Type K thermocouples come in a variety of sizes, shapes and mounting configurations. When choosing you decide based on what you want considering things like response time. Grounded or Ungrounded? Sheath material? I suggest you read up on Thermocouples with a focus on Type K and things like thermocouple response times and sheath types if you want a sheath type. Keep in mind the sensor (thermocouple) leads must be the same as the thermocouple alloy.

Personally of what you listed I would use the one you refer to as "the big one".

Ron

 

I guess, the previous regler was a simple mechanical on-off switch combined with timer. What is the reason to use a PID regler where a simple switch worked well ? I saw a big 50kW ovens, with fan inside, and a on-off regler was used, too. In addition, you need to tune that PID regler, it's not an easy procedure. Regler autotune function is not usefull, in most cases.
And also use a separate timer for the oven

 

What is the reason to use a PID regler where a simple switch worked well ?

The normal on-off switch will cost half of pid regulator but I think pid regulator Will be more precise and durable.

 

The PID regler mentioned in your first post has the SSR output. It means, you should buy a Solid State Relay to drive the oven heater.
If a general purpose mechanical on-off thermostat is combined with a SSD relay, it will be very durable. Of course, you need a small 24VDC power supply to drive the SSR.
In other hand , take in mind that SSR is quite sensitive to voltage spikes and overloads. Should be mounted on a heatsink located in a cool place. I have some practics with SSR in an industrial heaters, it's good in a comfortable environment only. After a year of use, were replaced to mechanical contactors.
As about precision- usually it's not a crucial parameter in an ordinary oven