TESTO 6681 Instruction Manual page 33

M12 plug-in connection (5-pin) connector (2)
Pin Assignment.
1 - Ch 2
2 + Ch 2
3 + Ch 3
4 - Ch 3
5 PE
1.3.3.5 Creating the PE/earthing terminal
As the testo 6681 has a metal housing, we recommend that the instrument
be earthed. This can be done using the earthing terminal within the
instrument (1) or the earthing terminal outside of the instrument (2).
Only use the external earthing terminal in dry interiors.
testo 6681 Ethernet
- 1.3 Commissioning 33