HEIDENHAIN iTNC 530 HSCI - Page 373

23 – 374 HEIDENHAIN Service Manual iTNC 530 HSCI
Evaluation using
the key matrix
The keys are evaluated via a matrix. Every key is located at a crosspoint of SL (= scan line) and
RL (= return line).
--> See ”Key matrix of the keyboard units” on page 23 – 382 and
--> See ”Key matrix of the screen soft keys” on page 23 – 392.
Figure: Principle of the key matrix
Flowchart Is a line (connecting element, board), the key element of the keyboard or the soft-key row of the
screen defective?
No
Yes
Use the key matrix to find a key that is controlled via
the same RL line as the defective key (and which
functions in the selected operating mode).
Is there any reaction?
No
Yes
The matrix lines (plug connections, soft-key rows,
keyboard PCB) are okay! It is likely that the
key's pressure contact is defective.
The matrix line is interrupted.
The defect is due to the plug
connections, the soft-key or
the keyboard PCB.
Press this key.
Use the key matrix to find a key that is controlled via
the same SL line as the defective key (and which
functions in the selected operating mode).
Is there any reaction?
Press this key.
Checking the keys