HEIDENHAIN iTNC 530 HSCI - Read-Back Outputs

12 – 150 HEIDENHAIN Service Manual iTNC 530 HSCI
12.1.5 Read-back outputs
The read-back outputs are a special feature of the HSCI bus diagnosis.
With this method, important outputs can be interrogated at the terminal and returned as inputs. This
increases the safety of these outputs.
With standard outputs only the output level 0 or 1 is set, without "checking back", whether this level
is actually output at the terminal.
Example:
In the HSCI bus diagnosis, the "Control is ready" output is available as input. It is, however, not a normal
input, but a read-back output!
The signal designation is I_RO_MC_RDY (Input Readback Output MC Ready).
Figure: The input I_RO_MC_RDY is a read-back output.
Figure: The level can be measured at the terminal RO X9.3a.