Rockwell Automation 8520-GUM 9/Series CNC Grinder Operation and Programming Manual Documentation Set - Manual (Page 414)

Axis Motion
Chapter 12
12-42
The previous sections described the basic function of CSS with different
grinding machine configurations. This section includes some specific
considerations for CSS operation.
Enabling (M58) and Disabling (M59) CSS Mode
The G96 mode must first be enabled by programming an M58 code. G96
is modal and remains active until it is cancelled by the G97 code or
disabled with an M59 code.
Use M58 or M59 to turn constant surface speed mode on or off. When
M59 is programmed, the control ignores G96 mode and the spindle
revolves at whatever speed it was at when the M59 was executed. If an
M58 is executed to restore the G96 mode, the spindle immediately changes
speed (if necessary) to maintain the correct surface speed.
If an S--word is programmed in the same block as an M59, G96 mode is
ignored but the S value is registered in memory as the constant surface
surface speed to be used if CSS is reactivated. The spindle speed does not
change relative to diameter.
When programming M58, the M59 code is cancelled and the G96 mode
becomes active again. The spindle returns to the previous G96 surface
speed unless an S--word was programmed in a previous M59 block.
ATTENTION: Restoring the constant surface speed mode
might cause the spindle speed to change rapidly depending on
the grinding wheel position relative to the active CSS axis.
Programming G96 with no S- word
When changing from G97 to G96 mode, if an S--word is programmed in
the G96 block the spindle changes speed to produce the surface speed
value indicated by the S--word. If no S--word is programmed in the G96
block, the control uses the current surface speed as the CSS value to be
maintained.
In Example 12.18, modes are switched from G97 to G96, but there is no
S--word programmed in the G96 block. When the G96 is executed,
initially the spindle does not change from the 5,000 rpm programmed in
the G97 block. When a change in diameter is made, the control changes
spindle speed to maintain the surface speed that was effective when the
spindle was running at 5,000 rpm at the previous diameter.
12.5.5
Notes on Constant Surface
Speed Mode (G96)