The transmitter output stance from what is known as “live zero”. This system has specific advantages
- The systems automatically alarms when the signal system becomes inoperative.
- The output areas is linear ( Ratio of 1 : 5).
DEAD ZERO SIGNAL:
The advantage is that it does not have to be biased to true zero. A “Live zero” gives the computer additional information, so that it can takes appropriate alarm action in case of a measurement failure, because it can discriminate between a transmitter operating, but transmitting a zero measurement and a failure, in the signal system.