7SR18 Applications Guide
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1.2 Binary Inputs
Each Binary Input (BI) can be programmed to operate one or more of the relay functions, LEDs, output relays etc.
These could be used to bring into the Relay such digital signals as Inhibits for protection elements, trip circuit
supervision status etc.
1.2.1 Alarm and Tripping Inputs
A common use of binary inputs is to provide indication of alarm or fault conditions e.g. transformer Buchholz Gas
or Buchholz Surge conditions. The Binary Inputs are mapped to LED(s), waveform storage trigger and binary
outputs. Note that transformer outputs which require high speed tripping, such as a Buchholz Surge, should be
wired to a binary input to provide LED indication and also have a parallel connection wired to directly trip the
circuit via a blocking diode, see Figure 1.2.1-1
Figure 1.2.1-1 Example of Transformer Alarm and Trip Wiring
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