Siemens SINUMERIK 840D sl Function Manual page 609

27001 Axis %1 error in a monitoring channel, Code%2, values: NCK%3, drive %4
Error codes 44-57 cannot be clearly assigned to an error cause. For the monitoring functions that run internally
(e.g. SG), monitoring limits are internally generated that are referred to a monitoring clock cycle.
Example: SG1 = 2000 mm/min, monitoring clock cycle = 12 ms
If SG1 is active, then a check is made in every monitoring clock cycle (MCC) as to whether SG1 was exceeded.
This means that in MCC[n], based on the actual value, a positive and negative actual value limit is defined
that may not be exceeded in MCC[n+1] in order to still comply with SG1.
SG1 = 2000 mm/min = 33.33 mm/s = 0.4 mm/MCC (for each 12 ms)
If the axis moves more than 0.4 mm in a monitoring clock cycle, then SG1 would be violated.
The limit values, specified above, in MCC[n+1] are then
Positive: Position actual value (MCC[n]) + 0.4 mm
negative: position actual value (MCC[n]) -0.4 mm
The resulting monitoring limits (positive and negative) that are, in turn determined independently for both
monitoring channels (NCK and drive) are also compared just like the safe actual positions (refer to fault code
3). The comparison is to check for a difference < MD36942 $MA_SAFE_POS_TOL.
If the difference is greater than MD36942 $MA_SAFE_POS_TOL, then the appropriate fault code is output.
The limit values are then re-generated and compared in every monitoring cycle independently of whether the
associated monitoring function is active or not.
This means that there are three possible causes for this fault code group.
Causes and remedy
Possible cause 1 (only when commissioning or changing the MD)
The tolerance value for the monitoring function is set differently for the NCK and drive. This situation actually
only occurs when commissioning the system or making changes and is generally already covered by the
previous fault codes.
Remedy:
Set the relevant machine data the same.
Possible cause 2 (in operation)
The limit values are determined based on the actual value. This means that when the safe actual values of
the NCK and drive differ then the limit values are also different by the defined clearance → i.e. the fault code
corresponds to the fault image of fault code 3. This is determined by checking the safe actual positions.
Remedy (refer to fault code 3)
Possible cause 3 (in operation)
The associated monitoring function is already active in a monitoring channel - while in the other monitoring
channel another monitoring function is still active.
This is the case if the safe actual positions of the NCK and drive do not differ but instead there is an entry in
drive parameters r9710/r9711 (and the 1 appears in parameter r9725) → i.e. the fault code corresponds to
the fault profile of fault code 1. This can also be identified using the fault message if for %3 = supplementary
info comparison value NCK or %4 = supplementary info comparison value drive no real limit value is output
but only the value of the calculated tolerance (refer to the example above (SG1 = 2000 mm/min = 0.4 mm/
monitoring clock cycle), a value of 400 would be displayed as 4%).
Remedy: refer to fault code 1.
44
Upper limit value for SG1 = position actual value + MD36931 $MA_SAFE_VELO_LIMIT[0] referred to a mon‐
itoring clock cycle
Remedy
Refer to Section 44-57 (hidden fault code 3 or 1)
45
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
11.2 NCK safety alarms for SINUMERIK 840D sl
Diagnostics
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