HEIDENHAIN TNC 306 Service Manual User Manual
Page 124
HEIDENHAIN Service
Cams for "Reference End Position":
The reference marks can either be traversed manually using the axis directional keys or automatically with the start key. It is not necessary to enter a code number
for the manual traverse as was the case with preceding TNC contouring controls. The traverse direction for the automatic traverse of the reference end marks is set
in the MP1320. In order to invert the predetermined traverse direction, a cam for "reference end position" is required. The triggering signals for the "reference end
position" are assigned to free PLC inputs. These PLC inputs are connected to the PLC markers M2506 and M2556 to M2559 via the PLC software.
Linear Encoder with Distance-Coded Reference Marks (MP1350.X = 0):
If the triggering signal "reference end position" is set when starting ref. mark traverse, the axis traverses in the direction opposite to that set in the MP1320. If the
triggering signal "reference end position" is only set during automatic traverse, the TNC ignores this signal. Thus, there must be at least two reference marks
within the range of the "reference end position". Reference mark evaluation takes place either in the range of the "reference end position" or else beyond this range.
In case of an evaluation beyond the software limit switch range, the axis traverses automatically to the software limit switch after evaluation.
Linear Encoder without Distance-Coded Reference Marks (MP1350.X = 1):
The traverse direction is automatically reversed, if the axis traverses the cam for "reference end position" during automatic traverse. If the axis is already in the range
of the "reference end position" when starting, the axis immediately traverses in the opposite direction. For this reason the reference mark my not be within the "reference
end position" range.
Special Operation: Linear Measurement with a Rotary Encoder (MP1350.X = 2):
The axis traverses automatically to the cam for "reference end position" at the predetermined feed rate (MP1330). The axis is started at a reduced feed rate (MP1331)
in the opposite direction; the first reference mark is evaluated after the end of the "reference end position" range has been reached. Then the axis is stopped. If the axis
is already in the "ref. end position" range when starting, it traverses immediately with the reduced feed rate (MP1331) in the direction opposite to that indicated in
MP1320.
Linear Encoder with Distance-Coded Reference Marks (MP1350.X = 3):
If the triggering signal "ref. end position" is set during reference mark traverse, the axis traverses opposite to the direction set in MP1320. The signal "reference end
position" is not ignored by the TNC, if it is only set during automatic traverse. The traverse direction is reversed immediately. Thus, no reference marks are required
in the "ref. end position" range.
R.H. TNC 306/335/360/2500
1.0 CNC 234/306
29.06.94 26.2
8.1