16
Festo — CMMT-AS-...-S1 — 2021-04d
Product overview
Term/abbreviation
Explanation
t
SBA,Out
Max. delay for diagnostic feedback (≤ permissible reaction time when a
safety sub-function is requested
1)
+ 10 ms)
n
Rotational speed
1) see Technical data, safety reference data SBC
Tab. 6: Legend for SBC timing
Requirements for the brakes
•
Check the brakes used for suitability for the application.
As a rule, the brakes used are holding brakes. This means the brakes are well suited to keeping the
motor at a standstill.
The internal holding brake of the motor is also used for the safety sub-function SBC. Please be aware
of the following constraints:
–
The holding brake must be designed for the load torque that is to be stopped.
–
The specifications for the holding brakes permit a certain amount of movement until the full
holding torque is reached. This must be taken into account in the design of the vertical axes and
configuration of the safety sub-function SBC.
–
“Reserves” should be factored in when selecting the motor plus holding brake, e.g. operation at no
more than 2/3 of the nominal torque. The holding brakes in the motors are usually designed so that
the motor shaft will come to a standstill without coasting at loads below 70% of the nominal torque.
–
Depending on the hazard situation, the holding brake must be designed with a correspondingly
higher nominal torque.
–
When designing the holding brake, the additional load torque for the brake test must be consid-
ered.
The number of clamping and braking applications for the clamping unit is limited by its wear.
1. Observe the corresponding specifications in the data sheet.
2. Replace clamping unit before the maximum number of clamping applications is reached.
3. Replace clamping unit if the emergency brake features of the clamping unit have to be used. Note
the permissible number of emergency braking applications.
Brake test
•
Check whether a brake test is required. The DGUV information sheet “Gravity-loaded axis” pro-
vides information on this.
4.1.4
Safety sub-function SS1
Fig. 8: Symbol for SS1
The function described here implements the safety sub-function SS1-t according to EN 61800-5-2.
