2 controlling the tool changer – HEIDENHAIN TNC 407 (243 020) Technical Manual User Manual
Page 353
15.2 Controlling the tool changer
Controlling the tool changer, i.e. positioning the changing arm and carousel and the complete tool-
change sequence is performed by the PLC. The NC handles tool management, i.e. tool life, tool
pocket assignment and evaluation of the TOOL DEF and TOOL CALL blocks.
NC and PLC communicate by markers and words.
When a TOOL CALL BLOCK is executed the tool geometry of the defined tool is taken from the tool
table. With Marker M2717 the PLC can activate the tool geometry of the tool defined in W264.
M2717 can only be activated together with a strobe or when the axis is stationary (
∗
off). With this
marker the PLC can ensure that the current tool geometry is active even when the tool changing
process is interrupted.
The TOOL DEF block can be used to pre-position the tool changer. After a tool has been changed,
the next tool is programmed with TOOL DEF. The PLC evaluates the tool and pocket number and
pre-positions the tool changer at the follow-up tool.
Example of NC program:
.
.
.
TOOL CALL 1 Z S500
TOOL DEF 2
L Z+20 R0 F500 M03
.
.
.
TOOL CALL 2 Z S1000
TOOL DEF 3
.
.
.
Variable and Fixed Pocket Coding
The system can be operated with either variable or fixed tool pocket coding.
Machine parameter MP7480 defines whether the tool number or the pocket number is transferred
to the PLC. For variable pocket coding the pocket number must be transferred to the PLC (MP7480
= 3 or 4). With fixed pocket coding it is advisable to work with the tool number (MP7480 = 1 or 2).
When executing a TOOL CALL or TOOL DEF block, depending on the setting of MP7480, the NC
transfers either only the tool number or the pocket number and the tool number of the programmed
tool to the word W262 or W262 and W264 respectively. The strobe marker M2046 (TOOL CALL) or
M2047 (TOOL DEF) is set. The NC does not reset these strobe markers until the PLC sets marker
M2483 (TOOL CALL) or M2484 (TOOL DEF) after processing the tool or pocket number. The
machining program is resumed when strobe markers M2046/M2047 are reset.
If tool number 0 is executed, then NC sets marker M2400 and this is not reset until there is a TOOL
CALL for another tool.