8-1
DP/PA Link and Y Link Bus Couplings
A5E00193841-011
Operation of the DP/PA Link and the
Y Link
Overview of contents
Section Topic Page
8.1 Start-up delay 8-1
8.2 Start-up characteristics 8-2
8.3 Behavior following specific events in redundant operation 8-6
8.4 Reading and writing records 8-7
8.5 Identification data 8-9
8.6 Replacing faulty modules 8-11
8.7 System changes during operation 8-11
8.8 IM 157 firmware update 8-12
Some of the following details apply to both the DP/PA link with its PA field devices
and to the Y link with its underlying DP slaves. In these instances, the following
terminology will be used in the interest of clarity:
“Link” stands for both the DP/PA link and the Y link.
“Slaves” stands for both the PA field devices and the underlying DP slaves.
“Underlying master system” stands for both the PA master system and the
underlying DP master system.
8.1 Start-up delay
During start-up, the link involves the slaves of the underlying master system in the
data cycle. The slaves are parameterized and configured and the inputs of the
slaves are read in.
To ensure a reproducible start-up and to avoid unintentional switching of the
outputs, the link issues CLEAR frames on the underlying master system during this
phase, i.e. the outputs of the slaves are put into a safe state.
Start-up behavior depends on the configured start-up characteristics of the system
configuration:
8