Calculate a BMC for Thermocouple and RTD function with a Fluke 5500A

[grivasl]

Hi i´m new in this forum

i have a fluke 5500A (multifunction calibrator)and i need to calculate a BMC for Thermo couple a RTD function, the problem is that when i sent to calibrate the equipment i get a certificate with only Uncertainties on voltage sorce and resistance source, because we use trhis source to simulate temperatura, i need to sent again to claibrate the equipment in this functions or how can i use this uncertainties to calclulate BMC on TC and RTD

Thx in advance

[BradM]

Well, hello! Welcome to the Cove!

I have posted a link to another thread on BMC. I hope it can provide you some assistance.

http://elsmar.com/Forums/showthread....&highlight=BMC

Are you compensating the cold junction for thermcouples when calibrating instruments? What accuracy are the temperature instruments you are calibrating?

How good is the lab that calibrated your Fluke ? I would think they would have that information available. Have you tried contacting them?

Do they show a verification of the thermocouple function/cold junction compensator?

What does the original documentation that came with your calibrator say?

Here is the link to the Fluke specifications. Don't know if it is any assistance.

http://us.fluke.com/usen/products/sp...(FlukeProducts)

NOTE: These are 1 year specifications, so they will degrade after a while.

[grivasl]

thanks Brad

i,m calculating the BMC to put in the scope, the problem is that, idont have uncertainties for the thermocuople and RTD range because when we sent the equipment to calibrate we only calibrate the voltage source and the resistance saource, because this source we use it to simulate.

my question is if my equipment with the calibration shows that is working prperly can i use the manual specifications o ineed to send my equipment again and ask to calibrate in all the range of thermocouples an RTD, so i can get uncertainties in all the range of simulated temperature

thanks in advance

[BradM]

Thanks for the reply. I am still a bit confused.

Do you use the Fluke 5500 to simulate thermocouple? Do you hook the thermocouple up directly, or do you utilize some type of cold junction compensation?

The output of the Fluke 5500 should have been verified for TC accuracy, with some level of uncertainty calculated in their measurements.

As far as using the mfg. spec's for the 5500, that would be a start. Also, you would need to accomodate for the age of your equipment, erro with connections, error with type wire used, etc.

Is this any help?

[jfgunn]

I can only speak from the standpoint of a 5520A instead of a 5500A. The Accuracy specifications from Fluke for the 5520A include the measurment of uncertainty from the clibration of the unit. This assumes you have the unit calibrated by Fluke.

If you have the unit calibrated by fluke, just take the Accuracy specification for TC simulation and treat it as a rectangular distribution. Add in some factor for thermocouple error and for resultion of the unit you are testing and call it done.

I have applied this to Voltage, Resistance, Current, etc for my 5520A. The one auditor who questioned it was OK once he got an explanation directly from Fluke.

If you sent the unit out for calibration to someone else or if the 5500 specs do not make the same claims as the 5520, then none of this applies.