Tool selection (T-word)

T <expr> Selection of tool place (modal)

The tool command determines the tool for the machining section. The tool number is forwarded to the programmable logic control (PLC) which loads the called tool in a tool magazine for a tool change. It should be noted that the T-word itself has no influence on the control-internal calculation of the tool geometry (tool data). For this purpose the D-word is used, which will be activated automatically with the T-word, under corresponding specification [1]-9.

The T-word initiates no tool change. Normally, this happens with the machine function M06.

The tool data [5], [6]-9.7 are saved within the tool data table of the CNC [6]-9.1. In addition, there is also the alternative option of communicating with an (external) tool data management system, which has either been provided by the user or which is distributed, and requesting tool data, via an additional interface. The access to internal or external tool data can be specified [1]-10.

In the interest of avoiding waiting periods between the time of loading and transfer of the tool data, the tool to be loaded from outside is normally requested one or more traverse-blocks before the actual inclusion of the tool data [1]-11. If several, possibly different, T-numbers are programmed before the D-number corresponding to the first T-Number, then all T-numbers before the last-programmed one are ignored. That means, the data supplied by the external tool management are neglected if the D-number of the tool does not match with the last programmed T-number.