Machine data
2.4 Axis-specific machine data
Parameter Manual
286
Operating Instructions, 08/2013, 6FC5397-8EP40-0BA0
Description:
Encoder frequency monitoring uses a hysteresis.
MD36300 $MA_ENC_FREQ_LIMIT defines the encoder limit frequency. The encoder
is switched off when this frequency is exceeded. The encoder is switched on
again when the frequency falls below that defined in MD36302
$MA_ENC_FREQ_LIMIT_LOW.
MD36300 $MA_ENC_FREQ_LIMITis entered directly in Hertz,
whereas MD36302 $MA_ENC_FREQ_LIMIT_LOW is a fraction, expressed as a percent-
age, of MD36300 $MA_ENC_FREQ_LIMIT.
MD36302 $MA_ENC_FREQ_LIMIT_LOW is therefore already correctly preset for most
of the encoders used.
Exception: In the case of absolute encoders with an En-Dat interface, the
limit frequency of the absolute track is significantly lower than the limit
frequency of the incremental track. A low value in MD36302
$MA_ENC_FREQ_LIMIT_LOW ensures that the encoder is not switched on again
until it falls below the limit frequency of the absolute track, and therefore
is not referenced until permitted by the absolute track. For spindles, this
referencing is carried out automatically.
Example EnDat encoder EQN 1325:
Limit frequency of the electronics of the incremental track: 430 kHz
===> MD36300 $MA_ENC_FREQ_LIMIT = 430 kHz
The limit frequency of the absolute track is approx. 2000 encoder rpm at 2048
increments/encoder revolution, i.e. the limit frequency is 2000/60 * 2048 Hz
= 68 kHz
===> MD36302 $MA_ENC_FREQ_LIMIT_LOW = 68/430 = 15%
Description: This MD is used to activate zero mark monitoring.
For PROFIdrive drives (the corresponding diagnostics system variables are not
currently supplied for incremental measuring systems):
For PROFIdrive, the permissible deviation must be set in the drive, *not* in
the NC. Zero mark monitoring reported by the drive is mapped to the NCK
according to the following rule:
0: no zero mark monitoring
100: no zero mark monitoring together with suppression of all encoder moni-
toring operations, i.e. not only alarm 25020 but also alarms 25000, 25010
etc. are suppressed.
>0 but less than 100: direct triggering of power ON alarm 25000 ( or
25001).
>100: attenuated error message: reset alarm 25010 (25011) is output instead
of power ON alarm 25000 (25001).
For absolute measuring systems (MD30240 $MA_ENC_TYPE=4):
Permissible deviation in 1/2 coarse increments between the absolute and the
incremental encoder track (one 1/2 coarse increment is sufficient).
36302 ENC_FREQ_LIMIT_LOW EXP, A02, A05,
A06
A3,R1,S1,Z1
% Encoder limit frequency for new encoder synchronization. DOUBLE NEW CONF
-
- 1 99.9, 99.9 0 100 2/2
36310 ENC_ZERO_MONITORING EXP, A02, A05 A3,R1
- Zero mark monitoring DWORD NEW CONF
-
-1 0, 0 0 - 2/2
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