Siemens 7SR157 Argus, Manual

Page: 19 / 180

Chapter 1 - 7SR157 Description of Operation
© 2022 Siemens Protection Devices Limited Chapter 1 - Page 15 of 38
Figure 2-8 LED Indication Label (partial)
2.6 Voltage Inputs
The voltage inputs ( Line Nom Voltage and Bus Nom Voltage ) can be defined with a nominal rating between 40
– 160V.
Voltage is sampled at 32 samples per cycle (1600Hz for 50Hz and 1920Hz for 60Hz systems). Monitoring
functions of the relay use fundamental frequency voltage measurement.
The waveform recorder samples and displays voltage input waveforms at 32 samples per cycle.
The appropriate VT connection and ratio is set in the CT/VT CONFIG menu.
2.7 Binary Inputs
The binary inputs are based upon opto-coupler technology and are operated from a suitably rated power supply.
The binary inputs are polarity conscious and will not operate if the DC supply polarity is reversed. For consistency
and safety it is advised that AC connections for binary inputs are made with the Live connection to the +ve
terminal and Neutral connection to –ve.
The user can assign any binary input to any of the available functions (INPUT CONFIG > INPUT MATRIX).
Pick-up (PU) and drop-off (DO) time delays are associated with each binary input. Where no pick-up time delay
has been applied the input may pick-up due to induced ac voltage on the wiring connections (e.g. cross site
wiring). The default pick-up time of 20ms provides ac immunity. Each input can be programmed independently.
Each input may be logically inverted to facilitate integration of the relay within the user scheme. When inverted the
relay indicates that the BI is energised when no voltage is applied. Inversion occurs before the PU & DO time
delay, see Figure 2-9.
Binary inputs can be configured for intentional operation from a 110/115 V rms a.c. power supply by setting of
0ms PU and 25ms DO timers. If additional pickup or drop-off time delays are required by the scheme logic, this
functionality can be achieved by programmable logic within the device. For AC operation, live and neutral wiring
should be routed as a pair in close proximity and limited to a length of less than 10m.
Each input may be mapped to any front Fascia indication LED and/or to any Binary output contact and can also
be used with the internal user programmable logic. This allows the relay to provide panel indications and alarms.
Each binary input is set by default to be read when the relay is in both the local or remote condition. A setting is
provided to allow the user to select if each individual input shall be read when the relay is in the local or remote
condition in the INPUT CONFIG > BINARY INPUT CONFIG menu.