What is the effect of the ODIS signal (Output Disable) that can be
set in the
DP1.INI or DP2.INI configuration file?
a) ODIS = 0 (TELEPERM mode):
• The last values are held and issued to the DP slaves if the AS
placed in the STO state.
• The DP slaves do not hear about the STO state of the AS
The backup behavior in this mode must be checked for modules, DP
PA units with backup capability.
b) ODIS = 1 (PROFIBUS-DP mode):
• The ODIS signal is output cyclically to the DP slaves after the
AS x88/TM has
transitioned to the STO state. The DP slaves assume the
defined safe state. The safety value can either be hardwired at the
unit or be
configured using COM PROFIBUS (hold last value or alternate
• The DP slaves hear about the STO state of the AS x88/TM.
• DP links to PROFIBUS-PA and AS-i transfer the ODIS signal to
subordinate bus systems.
In STO state, DP master and all DP slaves remain active on the DP
bus in either
mode. The DP slaves need therefore not have new parameter values
upon a transition in the STA state.