Beckhoff TwinSAFE EL6900 - TwinSAFE Reaction Times

Operation
EL690032 Version: 3.1.0
5.2.5 TwinSAFE reaction times
5.2.5.1 Typical response time
The typical reaction time is the time that is required to transmit information from the sensor to the actuator, if
the overall system is working without error in normal operation.
Fig.13: Typical response time
Definition Description
RTSensor Response time of the sensor, until the signal is made available at the interface. Typically
provided by the sensor manufacturer.
RTInput Response time of the safe input, e.g. EL1904 or EP1908. This time can be found in the
technical data. In the case of the EL1904 it is 4ms.
RTComm Response time of the communication. This is typically 3 times the EtherCAT cycle time,
since a new Safety-over-EtherCAT telegram has to be generated before new data can be
sent. These times depend directly on the higher-level standard controller (cycle time of the
PLC/NC).
RTLogic Response time of the logic terminal. This is the cycle time of the logic terminal and typically
ranges from 500µs to 10ms for the TwinSAFE logic terminal, depending on the size of the
safety project. The actual cycle time can be read from the terminal.
RTOutput Response time of the output terminal. This is typically between 2 and 3ms.
RTActor Response time of the actuator. This information is typically provided by the actuator
manufacturer
WDComm Watchdog time of the communication
The typical response time is based on the following formula:
3 3
typ Sensor Input Comm Logic Comm Output Actuator
ReactionTime RT RT RT RT RT RT RT= + +
*
+ +
*
+ +
with
5 4 3 1 10 3 1 3 20 48
typ
ReactionTime ms ms ms ms ms ms ms ms= + +
*
+ +
*
+ + =