3 s-override – HEIDENHAIN TNC 407 (243 020) Technical Manual User Manual
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4.1.3 S-Override
The spindle speed can be altered within certain limits by the S-override potentiometer . These limits
are fixed by machine parameter MP3310. However, the upper spindle speed-limit from MP3515
cannot be exceeded by S-override.
The %-factor which is adjusted by S-override is kept in Word W492 and W764. However, W764 be
changed by the PLC. As soon as a different value is entered here it will be adopted by the NC. In this
way the %-factor can be influenced by the PLC .
If W764 is not changed by the PLC, the normal override-function remains active.
MP7620 bit 3 determines whether the override is effective in 1% steps or according to a non-linear
characteristic curve. In the non-linear characteristic, the lower range changes in 0.01% steps, and in
the range over 2.5% the step is 0.75%. The range of override values in W492 and W764 lies
between 1 and 150 in 1% steps for the linear characteristic, and between 0 and 15 000 for the non-
linear characteristic.
MP3310.0 Limit with S-override (maximum)
Entry: 0 to 150 [%]
MP3310.1 Limit with S-override (minimum)
Entry: 0 to 150 [%]
Word
Function
Set
Reset
W492
%-factor - spindle-override
NC
NC
(NC
→
PLC)
W764
%-factor - spindle override
NC; PLC
NC; PLC
(PLC
→
NC)
MP7620 Feed-rate and spindle override
Entry: %xx0x
Bit 3
Override in 1% steps or non-linear
0 = 1% steps
1 = non-linear