11.03
3 Safety-Related Functions
3.5 Safely-reduced speed (SG)
© Siemens AG 2003 All Rights Reserved
SINUMERIK 840D/SIMODRIVE 611 digital SINUMERIK Safety Integrated (FBSI) - Edition 11.03
3-93
When SBH/SG is active in a configuration with 1 encoder, the speed is
monitored to ensure that it does not exceeded a maximum encoder limit
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 limit frequency and speed
Encoder pulses/rev.
Speed at maximum encoder limit frequency
200 kHz
300 kHz
420 kHz
2 048
5.800 rpm
8.700 rpm
12.300 rpm
1 024
11.600 rpm
17.400 rpm
24.600 rpm
512
22.200 rpm
34.800 rpm
49.200 rpm
Note:
1) 840D SW 3.6 and higher
Machine data 36926: $MA_SAFE_ENC_FREQ_LIMIT can be used to set a
limit frequency. The maximum value is 420 kHz, the lower limit and default
value is 300 kHz.
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.
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.
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. Cables to be used:
Siemens cable, Order No. [MLFB]: 6FX8002-2CA31-1CA0
2. Maximum permissible encoder cable length: 20 m
3. 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
4. The amplitude monitoring is active up to 420 kHz.
Speed monitoring,
encoder limit
frequency
Parameterizable
encoder limit
frequency
(SW 6.3.30 and higher)