Vaisala DMT340 - Manual (Page 133)

Chapter 4 _________________________________________________________________ Operation
VAISALA _______________________________________________________________________ 131
ONLINE STATUS
Live measurement (data available): relay active (C and NO outputs are
closed)
No live data (for example: error state, sensor purge or adjustment mode):
relay released (C and NC outputs are closed)
See Figure 70 on page 131 for illustrative examples of the
FAULT/ONLINE STATUS relay output modes.
1102-040
Figure 70 FAULT/ONLINE STATUS Relay Output Modes
FAULT/ONLINE STATUS relays are usually used in conjunction with
an analog output to obtain validity information for the output value.
NOTE If transmitter loses its power, all status-based relays are released
similarly to the case of an instrument failure.