ctrlX SAFETY "SafeMotion"
DANGER
Lethal injury and/or property damage caused by varia-
tions in the position detection
If an ACUROⓇlink encoder is used as safety technology
encoder, the Safe position resolution of the encoder
may be lower than the actual encoder resolution. This
may lead to an undetected positional variation between
detected and actual position with all safety functions of
the safe position. This must be considered in the risk
assessment of the machine.
The velocity of the ACUROⓇlink encoder is recorded at an interval of 1 ms
with a tolerance of ±0.5 %. The resulting tolerance of the actual value for the
velocity has to be taken into account for the risk assessment at the machine!
EnDat–2.2 encoder
Encoders with an EnDat-2.2 interface have to comply with the following
requirements so that they can be used as safety technology encoders in safety-
related applications up to SIL 2 or Category 3, PL d:
●
Measuring device types:
Functionally safe measuring instruments with serial data transfer via EnDat
2.2
–
Absolute length measuring device
–
Singleturn rotary encode
– Multiturn rotary encoders with gearbox
– Multiturn-rotary encoder with battery buffers
● Supply voltage: Only safe EnDat–2.2 encoders with a 12 V supply voltage are
supported.
● Resolution: Encoders with a resolution of a maximum of 48 bit are sup-
ported.
●
Limit speed: Only rotary encoders with a maximum permissible speed of
20,000 rpm can be used. Rotary encoders with a permitted speed higher
than 20,000 rpm can be used in connection with a safety function as the
speed monitors for exceedance of the maximum value of 20,000 rpm (e.g.
"Safe maximum velocity”).
In this case, the maximum acceleration must not exceed 250 000 rad/s² if
the encoder supports this.
●
Mechanics: The connection of encoder shaft and motor shaft or encoder
housing and motor housing, and the fixing device of the reading head of
linear encoders has to be dimensioned so that accidental loosening or
breakage of the connection can be excluded. The specifications of the
encoder manufacturer regarding the connection of encoder shaft and motor
shaft or encoder housing and motor housing or fixing the reading head the
for linear encoders have to be complied with.
Take remaining risks into consideration: see marginal note "Important instruc-
tions regarding inadequate connections of encoder shaft and motor shaft or
encoder housing and motor housing".
● Reliability: The "Mission Time" and the "Proof Test interval" of the encoder
have to be complied with. After the "Mission Time" has elapsed, the
encoder has to be decommissioned. When the "Proof Test interval" is over, a
"Proof Test" has to be carried out with the encoder or the encoder has to be
decommissioned.
Note: The drive system ctrlX DRIVE does not monitor or log the "Mission
Time".
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