Sensors

[ThierryBM]

What is the most precise temperature sensor:
To measure a temperature between -100 °C and 500°C.
Location area: heater duct.
Type of flow: air hot and cold.
Speed of the air: between 10 and 35 m/s.
Humidity: around 40%.

The loop is to control a fan speed with a set of 10 temperature sensors.

What is the best interface of connunication?
Do I need a PLC to written my equation loop?
What is the best deadzone to program between to ouput signal from the PLC or fan speed control?

I have many other questions I will split it.
Tks for your answer.

[theW]

Hi,

It seems that you're designing a system to measure temperature and adjust the speed of a fan based on this temperature. I troll this group for serial questions, so I will admit that I'm not an expert on this sort of application, but I think that NI can provide you with a hardware/software combination that would do what you wanted.

Check into our DAQ (Data Acquisition) boards for pulling the data into your computer; of course, this depends greatly on what sort of sensor you end up deciding purchasing. DAQ cards generally read a voltage from sensors, and I would imagine that some sensors may have a serial or other interface that could enable you to connect it directly to your computer, but the tradeoffs of this approach are mainly in the frequency with which
you update your temperature (scan rate). The DAQ card can also output specific voltages or digital signals to control your fan speed, depending on the interface of the fan.

A PC running LabVIEW would definitely be useful in processing the data and appropriately adjusting the fan speed based on an equation that you provide. LabVIEW is a graphical language that allows you to set this sort of thing up rather easily.

I hope this helps, let me know if you have further questions. Additionally, search or browse the www.ni.com website with the keywords DAQ and LabVIEW and you'll find a wealth of information.

Scott
National Instruments
Applications

[Henrik_Volkers]

Sensors: look for RTD sensors, the Pt100 should fit.
Depending on your needed accuracy an individual calibration of these sensors might be recommended.
You than can get a Pt100 in your range calibrated to 50mK. However 10 of them are worth a car. And you need a meter in the same category.....
Next point to look at is the dynamic of your air temperature and your control loop. high prcision pt100 are not as fast as termocouples TC.

Please post more specs