Siemens SINUMERIK 840C - Manual (Page 741)

09.95 10 Axis and Spindle Installation
10.5 Spindle installation, spindle functions
Description of the spindle modes
The following is a description of the various modes in which the spindle may be operated. The
individual modes can be programmed by NC (part program MDA, overstore), PLC or command
channel (CC). The functions that are then available are given in each case.
The various command sources (NC, PLC or CC) have different priorities, i.e. they can interrupt
or interlock each other.
The various switching conditions and interlocks are dealt with in the section headed ”Switching
logic”.
10.5.1 Open-loop control mode
General
In the open-loop control mode, the spindle is issued with a setpoint for speed (or cutting rate)
and direction of rotation. The setpoint that has been input can be altered by "Speed override"
when necessary.
Actual value acquisition
• The open-loop control mode normally requires no encoder for actual value acquisition
except if the spindle is to be used for thread-cutting or the "Revolutional feedrate" function
in which case an encoder must be mounted on the spindle.
• If an encoder is fitted, it is also used in the open-loop control mode for monitoring and
displaying the actual values (of speed and position). The encoder must be mounted
directly on the spindle so that the actual speed and position of the spindle can be
measured.
Selecting the open-loop control mode
Open-loop control mode is selected by NC, PLC or command channel. The following functions
are possible:
PLC: Request for open-loop control mode
•
Constant speed and direction of rotation:
–
IS:INITIALIZE
– set speed from MD 449*
– set direction of rotation with IS:SET ROTATION CW
CC: Request for control mode
•
Constant speed and direction of rotation:
–
”S external” function
– set S value (speed) and M3, M4 (rotation) or M5 (spindle stop) in user data of
command channel
NC: Request for open-loop control mode
•
Constant speed and direction of rotation
–
programming of S value, M3, M4, M5, G94, G95, G97
• Constant cutting rate
–
programming of S value, M3, M4, M5 and G96
• Thread-cutting
–
programming of S value, M3, M4, M5 and G33, G34, G35
© Siemens AG 1992 All Rights Reserved 6FC5197- AA50 10–51
SINUMERIK 840C (IA)