Siemens SINUMERIK 840D sl Function Manual page 45

Functionality of the "Position measuring system 1 / 2" interface signals in conjunction with the
"Controller enable":
DB31, ...
DB31, ... DBX2.1 (controller enable)
Setting the controller enable closes the machine axis position control loop. The machine axis
is in position control mode.
DB31, ... DBX2.1 == 1
Cancelling the controller enable opens the machine axis position control loop and, subject to
a delay, the machine axis speed control loop:
DB31, ... DBX2.1 == 0
Activation methods
The closed-loop controller enable for a machine axis is influenced by:
● NC/PLC interface signal:
– DB31, ... DBX2.1 (controller enable)
– DB31, ... DBX21.7 (pulse enable)
– DB31, ... DBX93.5 (drive ready)
– DB10, DBX56.1 (emergency stop)
● NCK-internal
Alarms that trigger cancellation of the controller enable on the machine axes. The alarm
responses are described in:
References:
Diagnostics Manual
Cancelling the controller enable when the machine axis is at standstill:
● The machine axis position control loop opens
● DB31, ... DBX61.5 == 0 (position controller active)
Cancelling the controller enable when the machine axis is in motion:
If a machine axis is part of an interpolatory path motion or coupling and the controller enable
for this is cancelled, all axes involved are stopped with a fast stop (speed setpoint = 0) and an
alarm is displayed:
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
DB31, ...
DBX1.5 DBX1.6
1 Any
0 1
0 0
0 0
1 → 0 0 → 1
0 → 1 1 → 0
A2: Various NC/PLC interface signals and functions
2.2 NC/PLC interface signals - only 840D sl
DB31, ... Function
DBX2.1
1 Position measuring system 1 active
1 Position measuring system 2 active
0 "Parking" active
1 Spindle without position measuring system
(speed-controlled)
1 Switchover: Position measuring system 1 → 2
1 Switchover: Position measuring system 2 → 1
45