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8.3
Offline phase on configuration errors (LOS)
The AS-i masters with advanced diagnostics offer the possibility to put themselves
into the offline phase when a configuration error on the AS-Interface occurs. This
way the security of the application can be ensured. The reaction to a configuration
error is very fast and the host can be relieved from this task. If there are any pro-
blems on the AS-i network, the AS-i can be switched to a secure state.
There are two different ways to parameterize the AS-i master for this feature:
• Every configuration error during normal operation in protected mode releases
the off-line phase.
• For each slave address, it can be chosen whether a configuration error on this
address will cause the offline phase or not. This information is stored in the list
of offline slaves (LOS).
The user himself can decide how the system reacts to a configuration error on
the AS-i. The AS-i master can release the off-line phase in critical situations, i. e.
only with certain slave addresses, whereas in less critical situations (if one of the
other AS-i slaves has a configuration error) only the error message is sent to the
host, but AS-i is still running.
The parameterization "off-line phase on configuration error" is also supported by
the "AS-i-Control-Tools" (command Master | Identity | Offline on configuration er-
ror).
Two ways to reset the error message "OFFLINE BY LOS" are possible:
1. Deleting of the complete list LOS of the affected AS-i circuit ("CLEAR ALL").
2. Voltage reset at the affected AS-i circuit.
By voltage reset at the AS-i circuit 1 the complete double gateway will be shut
down.
8.4
Functions of the AS-i fault detector
8.4.1
Duplicate address' recognition
If two slaves have the same address in an AS-i circuit, a duplicate address exists.
Because of this error the master can not send a request to each slave seperately.
At that time both repsonses overlap themselves on the line, it is impossible for the
master to recognize the slave response safely. It exists an unstable network beha-
viour.
The function "duplicate address' recognition" allows to recognize a duplicate
address and to indicate this both via superior fieldbus and in the AS-i Control
Tools.
Subject to reasonable modifications due to technical advances.
48
Pepperl+Fuchs Group · Tel.: Germany (6 21) 7 76-0 · USA (3 30) 4 25 35 55 · Singapore 7 79 90 91 · Internet http://www.pepperl-fuchs.com
Advanced Diagnostics for AS-i Masters
AS-Interface
Copyright Pepperl+Fuchs, Printed in Germany
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