Solution
the 9214 has a terminal block added onto the module which increases measurement accuracy and provides additional cold junction compensation.
The accuracy section of the manuals for these devices shows the best illustration of these differences. Beginning on
Page 7 of the 9213 manual and
page 8 of the 9214 manual:
The 9213 also has an avialable model that is conformal coated to protect against moisture. This is not available for the 9214.