Diagnostic Functions; Protection Mechanisms - Omron PRT1-SCU11 Operation Manual

Overview of PROFIBUS
Multi-peer Communication
Broadcast
Communication
Multicast Communication
1-1-5

Diagnostic functions

Extensive Diagnostics
Device Related
Diagnostics
Module Related
Diagnostics
Channel Related
Diagnostics
1-1-6

Protection mechanisms

Monitoring Time
Monitoring at the Master
tive to communicate with DPM1 master devices in a master-master
communication relationship.
In addition to logical peer-to-peer data transmission, PROFIBUS-DP provides
multi-peer communication (broadcast and multicast).
In the case of broadcast communication a master device sends an unac-
knowledged message to all other devices (masters and slaves).
In the case of multicast communication a master device sends an un-
acknowledged message to a predetermined group of devices (masters and
slaves).
Extensive diagnostic functions defined in PROFIBUS-DP enable the fast loca-
tion of error at slave devices. Diagnostic messages are transmitted over the
bus and collected at the master. Three levels of diagnostic messages are
defined:
• Messages concerning the general operational status of the whole device,
e.g. over temperature, low voltage.
• Messages indicating that an error is present in a specific I/O range of a
device, e.g. an 8-bit output module.
• Messages indicating an error at a given input or output, e.g. short circuit
on Output 5.
PROFIBUS-DP provides effective protection functions against parameteriza-
tion errors or failure of the transmission equipment. Time monitoring is pro-
vided both at the master and the slave devices. The monitoring interval is
specified when the system is configured.
The PROFIBUS-DP Master monitors data transmission of the slaves with the
Data-Control-Timer. A separate control timer is used for each slave. This
timer expires if response data is not correctly transmitted by the slave within
the monitoring interval. The user is informed when this happens. If the auto-
matic error reaction (Auto-CLEAR) has been enabled, the PROFIBUS-DP
Section 1-1
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