Question: How can you save code values for the 9400 ServoPLC fail-safe without the device command C0002 = 11?
Answer:
With the 9300 Servo PLC, it is possible to map codes (parameters) to RETAIN variables and to save these values fail-safe.
This proceeding cannot simply be transferred to the 9400 ServoPLC because the 9300 Servo PLC and the 9400 ServoPLC have a different initialisation sequence after power-on:
9300 Servo PLC:
In the initialisation sequence, the code values are restored before the RETAIN variable values are restored. Thus, the RETAIN variable values overwrite the code initialisation values as desired. 9400 ServoPLC (version ≤ V2.x):
In the initialisation sequence, the code values are restored after the RETAIN variable values. Thus, the code value last saved with C0002 = 11 unwantedly overwrites the value of the RETAIN variable assigned to the code. A remedy for 9400 ServoPLCs with firmware versions ≤ V2.x is described in the attached document. For firmware versions ≥ V3.x, you can set the initialisation sequence of codes and RETAIN variables and take advantage of the behaviour known from the 9300 Servo PLC.
