6 Assi
nin
Parameters to the Control and the PLC Pro
ram
6
03.96
6.9 Axes and spindles
6-136
Siemens AG 2000 All Rights Reserved
SINUMERIK 840D Installation and Start-Up Guide (IAD) – 04.00 Edition
The velocity is adapted internally in the SINUMERIK 840D. The setpoint is
limited on a percentage basis in MD 36210: CTRLOUT_LIMIT with reference to
the speed value entered in MD 1401: MOTOR_MAX_SPEED. An alarm is
generated if the setpoint is exceeded for the time period set in MD 36220:
CTRLOUT_LIMIT_TIME. The axes are braked down to zero speed along a
braking ramp when the position control loop is open (MD 36610:
AX_EMERGENCY_STOP_TIME). This MD must contain the time within which
the axis can brake to zero from maximum velocity.
MD 36210: CTRLOUT_LIMIT (maximum speed setpoint)
MD 36220: CTRLOUT_LIMIT_TIME (monitoring time for maximum speed
setpoint)
MD 36610: AX_EMERGENCY_STOP_TIME (braking ramp time in event of
faults)
Alarm “25060 axis [name] speed setpoint limitation”.
The monitoring function is provided to ensure that axes whose velocity is limited
in theory owing to the prevailing mechanical conditions (e.g. due to mechanical
limit frequency of pulse encoder) traverse correctly. The actual velocity monitor-
ing function is always active if at least one encoder is configured in the axis
(MD 30200 NUM_ENCS < > 0) which is lower than its limit frequency. Alarm
25030 is output when the threshold value is exceeded.
MD 36020: AX_VELO_LIMIT (threshold value for velocity monitoring)
MD 36610: AX_EMERGENCY_STOP_TIME (braking ramp time in the event of
faults)
Alarm “25030 axis [name] actual velocity alarm limit”.
The monitoring function is based on the continuous comparison between the
measured following error and the following error predicted on the basis of the
NC position setpoint. Contour monitoring is always active in position-controlled
operation. If the tolerance band is violated, then the “Contour monitoring” alarm
is generated and the axes are braked along a set braking ramp.
MD 36400: CONTOUR_TOL (contour monitoring tolerance band)
MD 36610: AX_EMERGENCY_STOP_TIME (braking ramp time in the event of
faults)
Alarm “25050 axis [name] contour monitoring”.
The frequency entered in MD: ENC_FREQ_LIMIT is monitored. If this is
exceeded, the “Encoder frequency exceeded” alarm is output and the axes
braked to zero speed. The “Referenced/synchronized” interface signal is reset
(DB31, ... DBX60.4, DBX60.5).
Example: Encoder with 2048 pulses mounted directly on motor, limit
frequency 200 kHz, n
max
= (f
limit
/ pulses) * 60 sec= 5900 rev/min
Result: It must be ensured that this speed is not reached at maximum axis
velocity (MAX_AX_VELO).
MD 36300: ENC_FREQ_LIMIT (encoder limit frequency),
IS “Encoder limit frequency exceeded 1” (DB31, ... DBX60.2),
IS “Encoder limit frequency exceeded 2” (DB31, ... DBX60.3),
Alarm “21610 channel [name] axis [name] encoder frequency exceeded”.
Dynamic
monitoring
Velocity limitation
Velocity monitoring
Contour monitoring
Encoder monitoring
(encoder limit
frequency
monitoring)
08.97
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