6 – 434 HEIDENHAIN Technical Manual TNC 426, TNC 430
S → S: Special tool 
follows a special 
tool 
7
77
7 With M4541 or the “F” field in the pocket table, specify whether the special 
tool should be returned to the original pocket in spite of variable pocket 
coding.
• No, M4541 = 0
The same logic program applies for single and double changer arms.
• Yes, M4541 = 1
Single and double changer arms have different sequences of pocket 
number transfer.
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
W264
M4541
W262
M4524
M4523
M4522
M4540
M4520
M4093
M4073
Pocket No. [new S]
Tool No. [new S]