Siemens SINUMERIK 840D Description Of Functions page 93

11.03
Speed monitoring, When SBH/SG is active in a configuration with 1 encoder, the speed is
encoder limit monitored to ensure that it does not exceeded a maximum encoder limit
frequency frequency. An appropriate alarm is output when the limit is exceeded.
Depending on the number of encoder pulses, the limit values are as follows for
a ratio of e.g. motor : load = 1 : 1:
Table 3-21
Encoder pulses/rev.
2 048
1 024
512
Note:
1) 840D SW 3.6 and higher
Parameterizable Machine data 36926: $MA_SAFE_ENC_FREQ_LIMIT can be used to set a
encoder limit limit frequency. The maximum value is 420 kHz, the lower limit and default
value is 300 kHz.
frequency
(SW 6.3.30 and higher)
This MD is set-up for each monitoring channel. MD 1326 is effective in the
drive: $MD_SAFE_ENC_FREQ_LIMIT.
The values in this MD are incorporated in the crosswise data comparison of the
monitoring channels.
Changing the MD values for an axis with a Standard 2 or Performance 1 control
module results in Alarm 27033 "Axis %1 Defect in a monitoring channel, Code
%2, Values: NCK %3, Drive %4". The 300 kHz limit still applies for these axes.
Limitations
The following secondary conditions/limitations are specified:
1.
2.
3.
4.
© Siemens AG 2003 All Rights Reserved
SINUMERIK 840D/SIMODRIVE 611 digital SINUMERIK Safety Integrated (FBSI) - Edition 11.03
Encoder limit frequency and speed
Speed at maximum encoder limit frequency
200 kHz
5.800 rpm
11.600 rpm
22.200 rpm
Note
Changes to this MD may only be made, carefully taking into account the
prevailing conditions.
This functionality is only supported by 611digital Performance 2 control
modules, High Standard and High Performance.
Cables to be used:
Siemens cable, Order No. [MLFB]: 6FX8002-2CA31-1CA0
Maximum permissible encoder cable length: 20 m
Encoder characteristics: "-3dB cutoff frequency" greater than or equal to
500 kHz
Examples for encoder used:
ERA 180 with 9000 pulses/rev and ERA 180 with 3600 pulses/rev from
Heidenhain
The amplitude monitoring is active up to 420 kHz.
3 Safety-Related Functions
3.5 Safely-reduced speed (SG)
300 kHz 420 kHz
8.700 rpm 12.300 rpm
17.400 rpm 24.600 rpm
34.800 rpm 49.200 rpm
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