Ramp Monitoring; The Sos Safety Function; The Ss2 And Sos Signals - Danfoss Vacon OPTEA Operating Manual

VACON® NXP Advanced Safety Options
Operating Guide

6.2.4.4 Ramp Monitoring

Speed
Zero speed
SS2 td1
Illustration 43: The SS2 Function in the Ramp Monitoring Mode
When ramp monitoring is used, zero speed monitoring and time monitoring are also used. Ramp monitoring monitors that the
deceleration speed obeys the set deceleration ramp. Select the monitored ramp with parameter SS2 Ramp Monitoring. The ramp
can be static or dynamically selected by a digital input or a fieldbus. It is possible to monitor the minimum ramp, the maximum
ramp, or both these ramps.
The ramp monitoring starts after the time delay that is set with SS2 td1 has passed. SS2 td1 starts when the SS2 function starts its
operation. The ramp monitoring ends when the SS2 function is reached. If the speed does not obey the parameterized ramp during
the monitoring, the STO(+SBC) function becomes active as a violation response.
When using dynamic ramp from digital input or fieldbus, the monitored ramp is determined at the moment when the function is
requested. The changes that are made after this do not affect the operation of the function.

6.2.4.5 The SOS Safety Function

When the SOS safety function is active, it monitors the rotation of the motor shaft. Use parameter SOS Revolution Limit to set the
allowed deviation from the position at the beginning of the monitoring. Exceeding the allowed deviation from the starting point
activates the STO(+SBC) function as a fault response.
The deviation that is set by SOS Revolution Limit applies to both the directions from the point at the beginning of the monitor-
ing. It is possible that the shaft rotates to one direction almost the maximum deviation and then to the other direction almost
double the allowed deviation without violating the monitoring.
During parameterization, the compatibility of the value of SOS Revolution Limit is checked against the pulses per revolution (Encod-
er/Proximity Sensor Number of Pulses) of the encoder. Setting SOS Revolution Limit below the capability of the encoder is preven-
ted. Example: With a Encoder/Proximity Sensor Number of Pulses value of 10, it is not possible to set SOS Revolution Limit below 0.1
revolutions.
The monitoring is based on the pulses reported by the encoder. With few pulses per revolution, the behavior may not be as expec-
ted. Example: When Encoder/Proximity Sensor Number of Pulses has the value 1, and SOS Revolution Limit has the value 1.00, the
violation of SOS monitoring is detected when the first pulse is counted. Depending on the actual position of the shaft and the en-
coder, this can occur with almost no rotation or slightly before the first full revolution.

6.2.4.6 The SS2 and SOS Signals

It is possible that the Active and Reached signals that are mentioned in this chapter are not always available in all interfaces.
80 | Danfoss A/S © 2021.06
SOS
SS2 td2
SS2 t1
N O T I C E
Safety Functions
SOS Revolution Limit
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AQ319736045637en-000101 / DPD01798