HEIDENHAIN TNC 151 Q Mounting Instructions page 23

3.6 Inputs "'Reference end position" and "Reference pulse inhibit"
Inputs PLC-Allocation TNC 151 B /
TNC 155 B
Multipoint
connector
TNC 151 Q/
TNC 155 Q
Multipoint connector
PLC-Power board
Reference end position X
Reference end position Y
Reference end position Z
Reference end position IV
-
EO
J5/9 J4/12
El
J5/10 J4/11
E2 J5/11 J4llO
E3 J5/12 J4/9
Reference pulse inhibit X E4
J6/1 J4/8
Reference pulse inhibit Y E5 J6/2
J4/7
Reference pulse inhibit Z
E6 J6/3
J4/6
Reference pulse inhibit IV E7 J6/4
J4/5
The TNC 151/TNC 155 is equipped with "software-limit switches".
The permissible travels of the machine
axes are programmed as machine parameters with reference to the location of the reference mark of the
specific transducer. (See "Software limit switch" , section 3.7,).
After switching on the mains power of the TNC 151/TNC 155, the reference points of all three machine axes
must be traversed over. After pressing the external Start-button, traversing over of the reference points is
performed automatically as per the entered machine parameters.
Please note: After entry of the code number 84 159 in the MOD-mode the reference points can also be traversed
over by means of the external direction buttons.
For location of reference points it is necessary for each machine axis to have a cam switch ("Reference end
position"). The cam for this switch must be positioned such, that when travelling towards the cam, the switch
closes shortly before reaching the reference point and remains closed whilst still traversing in the same
direction until the emergency stop switch has been passed. A rotary table axis is an exception. For this axis,
a permanent bridge from J5/12 (TNC 151 B/TNC 155 B) or J4/9 (TNC 151 QITNC 155 Q) to +24 V is required.
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