Section 5: Control And Logic Functions; Motor Start/Stop - Siemens 7SR105 Rho User Manual

Section 5: Control and Logic Functions

5.1

Motor Start/Stop

Settings are included for CB monitoring and CB control i.e. motor stop/start.
Motor start and stop commands can be initiated in one of three ways: via a binary input, via the data
communication Channel(s) or from the relay CONTROL MODE menu.
Gn Trip Time Alarm
The CB Trip Time meter displays the measured time between the trip being issued and the CB auxiliary contacts
changing state. If this measured time exceeds the Trip Time Alarm time, a Trip Time Alarm output is issued.
Gn Trip Time Adjust
This allows for the internal delays caused by the relay – especially the delay before a binary input operates – to
be subtracted from the measured CB trip time. This gives a more accurate measurement of the time it took for the
CB to actually trip.
Gn Start Motor Delay
The Start Motor Delay is applicable to a motor start commands received through a Motor Start binary input or via
the Control Menu. The status of this delay is displayed on the relay fascia as it decrements towards zero. Only
when the delay reaches zero will the start motor command be issued and related functionality initiated.
Gn Blocked Start Delay
The Start Motor command may be delayed by a Block Start signal applied to a binary input. This restrains the
start motor output whilst energised. If the Block signal has not been removed before the end of the defined time,
Blocked Start Delay, the relay will abort the start operation.
Gn Stop Motor Delay
The Stop Motor Delay setting is applicable to stop motor commands received through a Stop Motor binary input
or via the Control Menu. Operation of the Stop Motor binary output is delayed by the Stop Motor Delay setting.
The status of this delay is displayed on the relay fascia as it decrements towards zero. Only when the delay
reaches zero will the trip command be issued and related functionality initiated. Unlike a CB trip initiated by a
protection function a CB trip operation caused by a Motor Stop command will not initiate functionality such as
circuit-breaker fail, fault data storage, I
Gn CB Controls Latched
CB/contactor control for motor start and stop can be latched for extra security.
When Reset operation is selected, the control resets when the binary input drops off. This can lead to multiple
control restarts due to bounce on the binary input signal. Reset operation allows a close or trip sequence to be
aborted by dropping off the binary input signal.
When Latch operation is selected, the close or trip sequence continues to completion and bounce on the binary
input is ignored.
Gn Start Motor Pulse
The duration of the Start Motor Pulse is settable to allow a range of control devices to be used. CB antipumping
is provided to prevent Start and Stop Command pulses existing simultaneously.
The 'CB Fail to Close' feature is used to confirm that the control device is open at the end of the Close Command.
Gn CB Travel Alarm
The CB Open/CB Closed binary inputs are continually monitored to track the motor control device Status.
©2018 Siemens Protection Devices
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t measurement and operation counter.
7SR105 Rho Description of Operation
Chapter 1 Page 44 of 57