direct-reading

adjective

(of an instrument) calibrated so that a given quantity to be measured can be read directly off the scale without the need of a multiplying constant

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Examples from the Web for direct-reading

Historical Examples of direct-reading

For insulation tests on installations, direct-reading instruments are frequently used (see Ohmmeter).
The New Gresham Encyclopedia
Various