Hello all,
I am having a max 31855 connected with a k type thermocouple. The reading shows an error of 5 degrees with a fair fluctuation. any suggestions to overcome?
I have attached a picture. Plz do see that
srimech25:
Hello all,I am having a max 31855 connected with a k type thermocouple. The reading shows an error of 5 degrees with a fair fluctuation. any suggestions to overcome?
I have attached a picture. Plz do see that
The DataSheet for the MAX31855K gives the Thermal Characteristics with an error bounds of +- 2C.
A type-K thermocouple only produces 41.276uV/C
I see from your picture, only minimal power filtering, conditioning. No shielding, parallel probes with no shielding. Un Insulated (thermal) connections. If the junctions between the thermocouple wires and the MAX31855 are at a different or varying temperature that will generate errors.
What is your application?
I would add a RCL network on the VDD line, Box the MAX31855k's, insulate(thermal) the box. Over-sample and Average the readings. Create a calibration table for each sensor/MAX31855.
Also, I would add some signal Conditioning:
Chuck.
What is your application?
Chuck.
[/quote]
Wireless transient measurement
srimech25:
What is your application?Wireless transient measurement
So, you are measuring Wireless signals with a thermocouple. Good Luck. I guess the probe wires could act like a simple loop antenna.
Chuck.
No sir,
I have a rotating cylinder to which these temperature sensors are connected. I want to measure temperature when the cylinder is rotating for which i chose wireless method
srimech25:
No sir,I have a rotating cylinder to which these temperature sensors are connected. I want to measure temperature when the cylinder is rotating for which i chose wireless method
So the temperature sensors are mounted on a rotating cylinder.
I would consider the magnetic and electrical environment.
If your sensors are rotated thru a magnetic field, that motion will induce a current into the probes. Since the thermocouples generate very small voltages, the environment the sensor is placed in has to be considered.
Depending on the velocity of your probes, even the Earth's weak magnetic field could induce currents into your probe wires.
Reduce the cable length to a minimum, encase the sensors, and their leads in conductive foil, (simple aluminum foil works). Ground the foil.
You might even need to encase the converters and the Arduino in an electrically shielded box.
Chuck.
Thanks a lot for the valuable inputs sir. I am sure i will incorporate the safety measures
srimech25:
Thanks a lot for the valuable inputs sir. I am sure i will incorporate the safety measures
I hope it help.
Have Fun!
Chuck.
Can u suggest me material to shield the thermocouples and the ICs
srimech25:
Can u suggest me material to shield the thermocouples and the ICs
Just use common Aluminum foil
It should work just fine, as long as it is not in an acidic environment.
Chuck.
Thank you sir
Can u suggest me where i buy the battery for arduino fio?