Chapter 13
Control and Status Registers
General
The Control- and Status Registers are disabled by default, but can be enabled using the ABC Config Tool
(see 4-7 “Status / Control Word”). These registers form an interface for exchanging status information
between the sub-network and the fieldbus control system.
The main purpose of these registers is to...
• Report sub-network related problems to the fieldbus control system
• Ensure that only valid data is exchanged in both directions
• Enable the fieldbus control system to start/stop data exchange with selected nodes on the sub-
network
If enabled, these registers are located in the Input and Output data areas, which means that they can be
accessed from the fieldbus just like any other data in these areas. Their location can be specified freely,
however keep in mind that the memory locations occupied by these registers cannot be used for regular
data exchange.
Handshaking Procedure
A special handshaking procedure, which is illustrated in the two flowcharts below, must be followed
when accessing these registers to ensure that both parts receive proper information.
6WDUW
5HDG6WDWXV5HJLVWHU
6HW&5B+6B&21),50
WR65B+6B6(1'
&5B+6B&21),50
65B+6B6(1'"
<HV
'RQH
6WDUW
5HDG6WDWXV5HJLVWHU
:ULWHWR&RQWURO5HJLVWHU
:ULWHWR&RQWURO5HJLVWHU
7RJJOH&5B+6B6(1'
65B+6B&21),50
&5B+6B6(1'"
1R
1R
<HV
'RQH