Siemens 7SR105 Rho - Emergency Start; Figure 5-1 Logic Diagram: Circuit Breaker Status

7SR105 Rho Description of Operation
©2018 Siemens Protection Devices Chapter 1 Page 45 of 57
The controller should only ever be in 3 states:
The CB Alarm output is given where the Travelling condition exists for longer than the CB Travel Alarm setting.
An instantaneous CB Alarm is given for a 1/1 state – i.e. where the CB indicates it is both Open and Closed at the
same time.
CB Open
CB Closed
&
&
&
&
CB Alarm
≥
1
CB Open
CB Closed
CB Travel
Alarm DTL
Figure 5-1 Logic Diagram: Circuit Breaker Status
Gn Stop Motor Pulse
The duration of the CB open pulse is user settable to allow a range of CBs to be used.
The CB open pulse must be long enough for the CB to physically open.
Emergency Start
Operation of the Emergency Start binary input resets thermal capacity, resets number of starts, bypasses the
backspin check, checks plant conditions and then operates the assigned binary output contact.
CB Status
CB Open
binary input
CB Closed binary
input
CB is Open 1 0
CB is Closed 0 1
CB is Travelling between the above 2 states 0 0