pressure plus built-in temp sensor

[07-EDM-STI]

I've been searching for pressure and temp sensor that has a relatively high operating temperator, I found this site

http://www.kasensors.co.uk/pressure-sen ... search.htm

http://www.kasensors.co.uk/ASMT-Press-t ... sducer.pdf


I'm thinking of connecting the sensor to an E888, however the E888 manual says that it has 2 CJC inputs but the sensor I found has a built in NTC thermistor. I emailed already the site asking if they have 1/8 NPT sensor that can be used with E888.

I really don't know what is the difference of CJC and NTC temp sensors, I searched and found these

http://digital.ni.com/public.nsf/allkb/ ... 8E0024475B

http://en.wikipedia.org/wiki/Thermistor

anyone knows if these can work? I'm hoping it will with some calibration. thankes

[jhidley]

NTC stands for Negative Temperature Coefficient. It means that the resistance of the device decreases as the temperature of it goes up. A data logger will use this to measure temperature by applying a voltage through fixed resistance in series with this sensor. This forms a crude current source. Then the logger measures the voltage at the node between the resistor and the sensor. You will need to do some math to program the logger with the correct voltage versus temp transfer function. You can do all of this with the analog inputs on the E888.

The CJC inputs are for a type of thermocouple. A thermocouple is a device that actually generates voltage by the heating of two different metals. The sensors you linked can't be used with this input. It would be very cheap and easy for you to buy a type k thermocouple and plug it into the type k thermocouple inputs.

You can actually ignore all of the above as you don't need to know it. The sensor you linked already has the current source applied to the NTC element and an amplifier on it. All you need to do is supply +5V to the sensor and connect the pressure and temperature outputs of the sensor to two different analog inputs on the E888. Then of course program the transfer functions in the logger for the senors.

[07-EDM-STI]

thanks for the info, i'm glad E888 have 8 AV inputs, with this sensor I'll use 2

[OmarK]

Just to add...

Cold Junction compensations are performed using external sensors or the E888 internal temperature sensor, according to the following rules:
• If only one of the two external cold junction compensation sensors (CJC1 or CJC2) is present then that sensor is used for compensations on all thermocouple inputs.
• If both of the two external cold junction compensation sensors are present then sensor CJC1 is used for compensations on TC1 to TC4, and sensor CJC2 is used for compensations on TC5 to TC8.
• If neither of the two external cold junction compensation sensors are present then the internal temperature sensor is used for compensations on all thermocouple inputs.

Cold Junction Compensation Inputs (CJC1 and CJC2)
The cold junction compensation inputs are used to measure thermistor (2 wire temperature sensor) temperatures for thermocouple input compensation. If the thermocouple inputs are not in use, or when using the E816, these inputs may be used as general purpose temperature inputs. CJC1/2 inputs have internal 1K pull-ups, and are calibrated to use Bosch 0 280 130 023/026 sensors to read from -30ºC to 150ºC.

[07-EDM-STI]

thanks Omar

I got a reply for my email inquiry about the sensor. The thread is M10x1, unfortunately I need 1/8 NPT thread. The sensor seems very good since it has very high operating temperature but it won't fit to my application

[Martin]

Do you want a pressure sensor with a built in temp sensor?

What pressure range do you want and what temperature range do you want to measure?

[07-EDM-STI]

yes I'm looking for a 1/8 NPT pressure sensor and temp sensor

pressure range of 0 - 120 psi, temp up to 150 C. The operating temp is critical hopefully I can find 150 C operating temp.

[Martin]

150degC is a problem


I use some with -40 to 125Degc, 1/8th NPT

You cannot fit a pressure sensor in that kind of temps, look at different sensors and their specs and you will see they wont live at 150 DegC. Maybe you can find such a sensor, but i havent seen one?


Only option would be a remote press sensor and a dedicated temp sensor that will read the range you need.

[07-EDM-STI]

125 C is about the max temp I see in my defi gauge when my car had problems with the aux fan getting stuck up. Now I see 115 C oil temp. 125 C would be good enough for me, I just have to make sure to keep my oil as cool as possible like thermal wrapping my headers, etc.

[Martin]

where are you situated? send me a pm with your details and email address.