Configuring Hardware and Communication Connections STEP 7.pdf

13.5.2 Opening the GD Table
There are two ways of opening a global data table:
• Open the entire GD table for a subnet
• Open the GD table for a CPU
Configuring Global Data Communication
Opening the GD Table for a Subnet (Recommended)
• In the SIMATIC Manager select an MPI subnet and select the menu command
Options > Define Global Data.
Result: The GD table for the selected subnet is opened.
Opening the GD Table for a CPU
The following option for opening a global data table is recommended if you want to
retrieve the GD table from the CPU during servicing and when searching for faults.
1. Select the menu command GD Table > Open > Global Data for CPU. The
dialog box "Open" appears, in which you can select the project and station for
the required CPU.
2. Select one of the following options:
- "Online" to read the data directly from the CPU, or
- "Offline" to obtain the system data for the CPU from the offline project
3. Select the project and double-click the station in which the required CPU is
located to open it.
4. Select the "Blocks" object of the CPU whose GD table you wish to display.
5. Confirm your selection by clicking "OK."
Result: A global data table appears in which all CPUs participating in global
data communication are entered in the column headers. However, the table
only contains the values for the selected CPU.
To complete the empty cells of the GD table, you must update the table.
• Select the menu command View > Update. The GD table is now displayed with
all entries.
Configuring Hardware and Communication Connections with STEP 7
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