Configuring Hardware and Communication Connections STEP 7.pdf

Configuring Global Data Communication
Structure of the Status Double Word
The following figure shows the structure of the status double word and an
explanation of the bits set.
A bit remains set until it is reset by the user program or via a programming device
operation.
Any bits not listed are reserved and have no significance at present. The global
data status occupies a double word; to make it clearer, MD120 has been used in
the figure.
13.5.8 Compiling the GD Table for a Second Time
After editing the status rows and/or scan rate rows, recompile the global data table
to ensure that the new information is incorporated in the system data.
The system data generated in phase 1 are sufficient for running global data
communication. You can download this data to the CPUs from the programming
device. Phase 2 is necessary only if you want to change default values for the scan
rates or make entries in the status rows.
Configuring Hardware and Communication Connections with STEP 7
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