7SR210 & 7SR220 Applications Guide
Page 6 of 48 ©2018 Siemens Protection Devices Limited
1.2 Binary Inputs
Each Binary Input (BI) can be programmed to operate one or more of the relay functions, LEDs or output relays.
These could be used to bring such digital signals as Inhibits for protection elements, the trip circuit supervision
status, autoreclose control signals etc. into the Relay.
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 fig. 1.2-1:
Figure 1.2-1 Example of Transformer Alarm and Trip Wiring
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