Siemens SINUMERIK 840C - Manual (Page 312)

12.93 6 NC Machine Data (NC MD), NC Setting Data (NC SD)
6.6.2 Spindle-specific MD bits (spindle bits)
Bit 3 If the bit is set, no measuring circuit monitoring is performed.
Examples for measuring circuit monitoring:
• Check for encoder line breakage
• Check for contamination, if the encoder has a signal for contamination or if
the amplitude can be monitored (with unconditioned signal encoders).
Active: Immediately
Bit 2 Bit 2=1 The spindle is switched to C axis mode on Power On.
Bit 2=0 The spindle is (remains) in spindle mode after Power On.
Bit 1 Is used to match the programmed direction of rotation (M03 and M04) to the
main spindle's direction of rotation. When bit 1 = 0, a positive setpoint speed
is output for M03. The spindle's direction of rotation can be reversed over the
PLC with interface signal "Invert M3/M4" (DB31 DRK + 1).
Active: NC STOP
Bit 0 Automatic drift compensation with M19
The function ”Automatic drift compensation wth M19” has the same effect on
spindles as ”Semi-automatic drift compensation” for axes. The function is
activated with every M19 command (even if M19 is sent from the command
channel), if the function is selected via MD 521*, bit 0, and the end position is
approached in M19 operation.
With this function a drift compensation is performed for the spindle when the
setpoint position is reached in M19 mode (speed 0 crossing of actual speed)
so that the following error of the position control is reduced.
The compensation value is derived from the sum of the NC spindle drift (MD
401*) and the speed setpoint at zero speed. The result is smooth with a filter
and stored internally.
The speed setpoint which is sent to the DAC, is derived from the sum of the
smoothed internal drift value, the NC spindle drift machine data and the speed
setpoint.
The function is deactived by
• Deleting the maching data bit (the internal compensation value is deleted,
only NC MD 401* has an effect).
or
• Deleting the alarm ”Speed setpoint warning limit” (control direction
monitoring with M19) (the compensation value calculated internally is
deleted, only NC MD 401* remains active).
The compensation value is deleted on POWER ON.
Effects on other functions
• Tacho compensation
Tacho compensation is only active during constant movement.
The new function is only executed after M19 with an actual speed of = 0
no reciprocal effect.
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 6–127
SINUMERIK 840C (IA)