How to calibrate Temperature transmitter ?

First of all know your desired range then set the lower limit (LRV) and upper limit (URV) for transmitter min and max output. Carefully read the vendor document / user manual of Transmitter. Select the suitable communicator (eg Emerson 475 field communicator) set the LRV and URV using right PROTOCOL (HART or Foundationfilebus for most of modern / Smart Transmitters).

For verification use the Temperature Calibrators.

A wide range of temperature transmitter calibrator from different manufacturers (FLUKE, OMEGA etc) are available in market, many of these simulate the temperature for selected type of traducers. They generate precise simulated  input for transmitter to be calibrate. Such as Resistant in RTD mode and milivolts for Thermocouples.

First we get transmitter range in specification sheet and take decade box 

ex: range is 0 to 300 degree Celsius

apply 0 to 300 degree through resistance using of decade box

transmitter connect with 24 v dc power supply  and also connect hart in series

apply linear 25%,50%,75%,100% and check temp in transmitter display

transmitter linearity not match properly set zero or span according to error

error is near about zero to set zero and error is near abut span you check span