BBH SMX Series - Specific Response Times for FAST_CHANNEL and Fault Distance

Installation manual
HB-37420-810-01-25F-EN SMX100 Installation manual.docx Page 212 of 260
Version: 25F
6.2 Response time for FAST_CHANNEL
FAST_CHANNEL describes a characteristic of SMX to respond quicker to speed requirements
than this would be possible with the execution of the safety programs in normal cycle ( = 16 / 24
/ 32 msec ) The sampling time of FAST_CHANNEL is 2 msec + 2 msec for signalling at the bus.
The following response times can be specified:
• 6 msec (Worst Case Condition)
Safety note:
• When using FAST_CHANNEL you should bear in mind that shutting down within the
time specified above for a given speed threshold is only possible, if the sensor
information has a sufficient resolution. The smallest resolvable switching threshold of the
FAST_CHANNEL requires at least 2 edge changes on the corresponding sensor system
within a period of 2 msec.
• This function can only be used in connection with semi-conductor outputs.
• The FAST_CHANNEL may not act on SSI Listeners
6.3 Response times for fault distance monitoring
The following calculation schematic applies for calculating the Worst Case condition.
System speed to the sampling instant V(t)
System speed in case of SMX response: V
A
(tthreshold value for monitoring)
(tthreshold value for monitoring SLS or SCA ): V
S
= constant for all t
Parameterized filter value: XF = constant for all t
Maximum possible acceleration of the application: a
F
= constant for all t
Deceleration after shut-down: a
V
= constant for all t
Sampling instant for occurrence of the Worst Case event: T
Fault
Response time of the SMX systems: t
Response
For the Worst Case assessment it is assumed that the drive will initially move exactly to the
parameterized threshold with a speed v(k) and then will accelerate to the maximum possible
value a0.