Siemens SINUMERIK FM-NC Installation And Startup Manual page 137

03.96
Encoder monitoring
MD 36310: ENC_ZERO_MONITORING activates the zero mark monitoring
function. The value specifies the number of pulses that may be lost.
(zero mark
Special feature:
monitoring)
Value=100, i.e. the HW monitoring for the encoder is also deactivated.
MD 36310: ENC_ZERO_MONITORING (zero mark monitoring)
MD 36610: AX_EMERGENCY_STOP_TIME (braking ramp time in event of
faults)
Alarm "25020 axis [name] zero mark monitoring".
Encoder monitoring
Two actual value branches can be defined in the SINUMERIK 840D. These
actual values must then, however, be present in the hardware. The actual value
(encoder switchover
branch which is active for the position control can then be selected via the PLC
tolerance)
interface. When this switchover takes place, the actual position value difference
is evaluated. If this difference is greater than the value entered in
MD: ENC_CHANGE_TOL, then the alarm "Measuring system switchover not
possible" is generated and the switchover process is prevented.
MD 36500 ENC_CHANGE_TOL (maximum tolerance for actual position value
switchover)
IS "Position measuring system 1" (DB31, ... DBX1.5),
IS "Position measuring system 2" (DB31, ... DBX1.6),
Alarm "25100 axis %1 measuring system switchover not possible".
Setpoints
Setpoint
processing
interpolator
Control loop
model
CONTOUR_TOL
Following error
STOP_LIMIT_COURSE
STOP_LIMIT_FINE
POSITIONING_TIME
STANDSTILL_DELAY_TIME
STANDSTILL_POS_TOL
CLAMP_POS_TOL
Fig. 6-21 Monitoring with SINUMERIK 840D
Note
The time set in MD 36620: SERVO_DISABLE_DELAY_TIME (cutout delay
servo enable) must always be set to a higher time than the setting in
MD 36610: AX_EMERGENCY_STOP_TIME (braking ramp time in event of
faults). If this is not the case, the braking ramp in MD 36610 cannot become
operative.
 Siemens AG 2000 All Rights Reserved
SINUMERIK 840D Installation and Start-Up Guide (IAD) – 04.00 Edition
6 Assigning Parameters to the Control and the PLC Program
AX_EMERGENCY_STOP_TIME
Braking
ramp
Position
controller
ENC_CHANGE_TOL
ENC_FREQ_LIMIT
STSTILL_VELO_TOL
AX_VELO_LIMIT
IS "Position measuring system 1/2 active"
6.9 Axes and spindles
Speed set-
point
CTRLOUT_LIMIT
ENC_ZERO_MONITORING
Actual value
processing
SIMODRIVE
611D
drive
Actual value
processing
6
SIMODRIVE
611D
drive
6-137