Siemens sinumerik 840D sl Function Manual page 276

Detailed description
2.3 Master value coupling
Coupling type
Coupling type is defined by the following setting data:
SD43100 $SA_LEAD_TYPE[LA] (type of master value)
Switch-over between actual and setpoint value coupling is possible at any time, preferably in
the idle phase.
LA: Leading axis as GEO axis name, channel axis name or machine axis name (X,Y,Z,...)
0: Actual value coupling (this type of coupling must be used for external leading axes)
1: Setpoint coupling (default setting)
2: Simulated master value (note virtual axis, not evaluated for FA)
Readable system variable of the master value
The system variables of the master value can be read from the parts program and from
synchronous actions:
• $AA_LEAD_V[ax]; Speed of the leading axis
• $AA_LEAD_P[ax]; Position of the leading axis
• $AA_LEAD_P_TURN; Master value position: the component that is deducted in the
Readable and writable master value variables
The speeds and positions of simulated master values (when $SA_LEAD_TYPE[ax]=2) can
be written in and read from the parts program and synchronous actions:
• $AA_LEAD_SV[ax]; simulated master value speed per IPO cycle
• $AA_LEAD_SP[ax]; simulated position in MCS
Detection of synchronism
System variable $AA_SYNC[ax] can be read from the parts program and synchronous action
and indicates whether and in what manner the following axis FA is synchronized:
0: not synchronized
1: Coarse synchronism (according to machine data:)
MD37200 $MA_COUPLE_POS_TOL_COARSE (quick value for coarse synchronism)
3: Fine synchronism (according to machine data:)
MD37210 $MA_COUPLE_POS_TOL_FINE (quick value for fine synchronism)
The information from system variable $AA_SYNC[ax] corresponds to the assigned VDI
signals:
DB31, ... DBX98.0 (fine synchronism)
DB31, ... DBX98.0 (coarse synchronism)
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modulo reaction. The actual (non modulo-reduced) position of the master value is
$AA_LEAD_P_TURN+$AA_LEAD_P.
Special functions: Axis Couplings and ESR (M3)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0