INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Temperature controller and temperature sensor compatibility

Temperature controller and temperature sensor compatibility

(OP)
Hi,
I would like to use the PID Temperature Controller (link 1 below) along with the specific fluid temerature sensor (link 2 below).
(link 1) http://www.ebay.com/itm/D1S-VR-220-220V-Digital-PI...
(link 2) https://img.banggood.com/thumb/water/oaupload/bang...

I have both items and would like to use them together for the liquid temperature control.
However, can I do it? I understand that the controller probes changes in the current which flows through the sensor due to electrical resistance change caused by its temperature change. If so, is the specific temperature controller designed for the specific temperature probe type?

P.S. The sensor presented under the second link is from this controller:
(lnik 3) http://www.ebay.in/itm/DIGITAL-TEMPREATURE-CONTROL...

P.P.S. The controller in link 1 was bought with K type sensor (this sensor is not probably immersion one):
https://picclick.com/Digital-PID-Temperature-contr...

P.P.S. As the alternative I consider inserting the K type termocouple tip (shown in link 3) into the copper blind pipe and submerging this copper pipe in the liquid. Effectively the sensor would probe the copper T.

Thanks.

Regards

RE: Temperature controller and temperature sensor compatibility

The Freezer controller uses an oddball NTC sensor. I would avoid it at all costs.

The Sestos is a typical PID loop controller, using a choice of a number of readily available industrial sensors:
"2. Support multi sensor input (K,S,Wre,T,E,J,B,N,CU50,PT100)"

The K type thermocouple will work with the Sestos. It does not have North American color coding. If you hook it up backwards, applying heat will drive the indicated temperature in the wrong direction, downwards. Just reverse the connections.

Depending on what you're sticking the thermocouple into, there are several standard mounting approaches.

There are compression fittings (Brass or stainless) that are bored for standard thermocouple sheath diameters. They'll work for low pressure, like a water bath.

For higher pressures, there are thermowells, that weld/thread/flange fit into the pressure vessel and the thermocouple slides into a bore sized for the thermocouple.

Letting the thermocouple 'rest' against the bottom of the open copper pipe will provide terrible sensing due to lack of conductive heat from the copper to the rounded sheath tip.

There are hundreds of thermocouple vendors willing to make one in a custom length (if you need one that's longer or shorter) for you at very reasonable prices. You haven't mentioned temperature range or accuracy, but I syspect a type T would serve you better, if for no other reason than its inaccuracy is half that of K or J.



RE: Temperature controller and temperature sensor compatibility

(OP)
@danw2
Thank you for your detailed answer.
The accuracy would be +/-1degC.
Range is 88-90degC.
In terms of inserting the TCK into the blind copper tube I was thinking of using little bit of glycerine to make a good contact.
I thought to use the stuff that I have in first place which could do the work. Of course it can be also acquired in the shop.
Thank you for your reply.

RE: Temperature controller and temperature sensor compatibility

I would use a PT100 sensor. They are cheap, accurate, and in many applications they are the preferred sensor type.
NTC sensors are OK but can give accuracy issues, particularly if the length of cable between sensor and controller is long.
Thermocouples are great for higher-temperature applications, but since you are only going to 90 deg C they are not really needed.
IMO, the biggest issue with thermocouples is that they need expensive thermocouple wire for the connecting cable, so if there is much length involved it can get a bit unwieldy.

RE: Temperature controller and temperature sensor compatibility

The spec'd accuracy with a K type T/C at 0.2% FS for a -50 to 1300°C range is ±2.7°C.
The spec'd accuracy with a Pt100 at 0.2% FS for a -200 to 600°C range is ±1.6°C.

On that basis alone, I, too, would opt for a 3 wire Pt100 for this application. The Sestos unit appears to take 3 wire Pt100's. Not all 1/16DIN temp controllers do, many take 2 wire only which adds an offset error from lead wire resistance.

Using some kind of liquid/oil as a heat transfer medium in the copper tube is an excellent idea.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close