Acknowledging Faults; Additional Diagnostic Functions - Siemens Simatic Manual

Fail-safe function blocks for storage and retrieval machines
Warning
Cyclic synchronizing means that the two-channel structure is bypassed for the
position actual value processing, and is therefore not permissible. The specific
application defines just when synchronizing is permissible, and it is the responsi-
bility of the user to ensure that the correct logic interlocking is used.
3.2.4.7

Acknowledging faults

41. DIAG and ERROR are reset to 0 with a positive edge at ACK, assuming that no other fault is
active. The block immediately indicates that it can be acknowledged with a 1 signal at its out-
put ACK_REQ. ACK_REQ is reset to 0 after a positive edge at ACK.
3.2.5

Additional diagnostic functions

To optimize the system response, the currently effective position and velocity discrepancy can be
read out using the instance DB of the block for diagnostic purposes.
Note
F instance data can only be accessed from the standard program.
The actual absolute value of the velocity discrepancy is designated in the block as
"abs_v_discrepancy", and is in the instance DB at address DBW118 – the data type is INTEGER
The actual absolute value of the position discrepancy is designated in the block as
"abs_delta_pos", and is in the instance DB at address DBW120 – the data type is INTEGER
This data can be accessed from the standard program as shown in the following example:
S7-Distributed Safety/SIMATIC Safety - fail-safe function blocks for storage and retrieval machines
- 3-19 -