Siemens SINUMERIK 840D sl Function Manual page 90

Detailed description
2.1 Axis monitoring
Fault
Upon exceeding of the encoder limit frequency, the following occurs:
• Message to the PLC:
• Spindles
encoder limit frequency, the actual value system of the spindle is automatically
resynchronized.
• Axes
The following alarm is displayed:
21610 "Channel <Channel number> Axis <Axis identifier> Encoder <Encoder number >
Frequency exceeded"
The affected axis is stopped via the configured braking ramp in follow-up mode:
Note
If the encoder limit frequency is exceeded, the position-controlled machine axis must be
re-referenced.
References:
/FB1/Function Manual, Basic Functions; Reference Point Approach (R1)
2.1.5.2 Zero mark monitoring
Function
Zero-mark monitoring serves as a plausibility check for the actual values of the relevant
machine axis.
Note
The zero-mark monitoring is only active beneath the configured encoder limit frequency:
MD36302 $MA_ENC_FREQ_LIMIT_LOW (encoder limit frequency for encoder
resynchronization)
The type of zero-mark monitoring depends on the type of encoder used:
MD30240 $MA_ENC_TYPE (encoder type of actual-value acquisition)
24
DB31, ... DBX60.2 or 60.3 = 1 (encoder limit frequency exceeded 1 or 2)
Spindles are not stopped but continue to turn with speed control.
If the spindle speed is reduced so much that the encoder frequency passes below the
MD36610 $MA_AX_EMERGENCY_STOP_TIME
(Maximum time for braking ramp when an error occurs)
Basic logic functions: Axis monitoring, protection zones (A3)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0