Displaying and Modifying CPU Properties

4.11.1 Displaying and Modifying the CPU Operating Mode

You can query and modify the current operating mode of a CPU. There must be a connection to the CPU.

Follow the steps outlined below:

1. Select the menu command PLC > Operating Mode.

2. In the dialog box that is then displayed, select one of the following modes:

- Warm restart - Cold restart - Hot restart - STOP

!

Modifying the operating mode while your plant is in operation can lead to serious injury to personnel or damage to equipment if the program contains errors!

Before running the debugging functions, make sure that no dangerous situations can occur!

4.11.2 Displaying and Setting the Date and Time on the CPU

You can query and modify the current time on a CPU. There must be a connection to the CPU.

Follow the steps outlined below:

1. Select the menu command PLC > Set Date and Time.

2. In the dialog box that appears, set the date and time for the real-time clock of the CPU.

If the CPU is not equipped with a real-time clock, the dialog box for the time displays "00:00:00" and the date box has the value "00.00.00". This means that you cannot make any changes.

S7-SCL V5.3 for S7-300/400

4-32 A5E00290611-01

4.11.3 Reading Out CPU Data

You can display the following information about a CPU:

• The system family, CPU type, order number, and version of the CPU.

• Size of the work memory and the load memory and the maximum possible configuration of the load memory.

• Number and address area of inputs and outputs, timers, counters, and memory bits.

• Number of local data with which this CPU can work.

• Whether or not a CPU is capable of multiprocessing (CPU-dependent).

There must be a connection to the CPU.

Follow the steps outlined below:

1. Select the menu command PLC > Module Information. 2. Select the "General" tab in the dialog box.

4.11.4 Reading Out the Diagnostic Buffer of the CPU

If you read out the diagnostic buffer, you can find out the cause of the STOP mode or back track the occurrence of diagnostic events.

There must be a connection to the CPU.

Follow the steps outlined below:

1. Select the menu command PLC > Module Information. 2. Select the "Diagnostic Buffer" tab in the next dialog box.

4.11.5 Displaying/Compressing the User Memory of the CPU

Using this function, you can display information about the memory load of the CPU and, if necessary, reorganize the CPU memory. This is necessary when the largest free continuous memory area is no longer large enough to take a new object downloaded onto the CPU from the PG.

There must be a connection to the CPU.

Follow the steps outlined below:

1. Select the menu command PLC > Module Information. 2. Select the "Memory" tab in the next dialog box.

4.11.6 Displaying the Cycle Time of the CPU

The following times are represented within the two selectable limit values:

• Duration of the longest cycle since the last change from STOP to RUN.

• Duration of the shortest cycle since the last change from STOP to RUN.

• Duration of the last cycle.

If the duration of the last cycle comes close to the watchdog time, it is possible that the watchdog time will be exceeded, and that the CPU will change to the STOP mode. The cycle time can be extended, for example, if you test blocks in the program status. To display the cycle times of your program, there must be a connection to the CPU.

Follow the steps outlined below:

1. Select the menu command PLC > Module Information. 2. Select the "Cycle Time" tab in the next dialog box.

4.11.7 Displaying the Time System of the CPU

The time system of the CPU includes information about the internal clock and the time synchronization between multiple CPUs.

There must be a connection to the CPU.

Follow the steps outlined below:

1. Select the menu command PLC > Module Information. 2. Select the "Time System" tab in the next dialog box.

4.11.8 Displaying the Blocks on the CPU

You can display the blocks available online for the CPU.

There must be a connection to the CPU.

Follow the steps outlined below:

1. Select the menu command PLC > Module Information.

2. In the next dialog box, select the "Performance Data/Blocks" tab.

S7-SCL V5.3 for S7-300/400

4-34 A5E00290611-01

4.11.9 Displaying Information about Communication with the CPU

For each CPU, you can display information online about the selected and maximum transmission rates, connections and the communications load.

There must be a connection to the CPU.

Follow the steps outlined below:

1. Select the menu command PLC > Module Information. 2. Select the "Communication" tab in the next dialog box.

4.11.10 Displaying the Stacks of the CPU

By selecting this tab, you can display information online about the content of the stacks of each CPU. The CPU must be in the STOP mode or must have reached a breakpoint.

Displaying the stacks is extremely useful to help you locate errors, for example when testing your blocks. If the CPU changes to STOP, you can display the interrupt point with the current status bits and accumulator contents in the interrupt stack (I stack) to find out the cause (for example of a programming error).

There must be a connection to the CPU.

Follow the steps outlined below:

1. Select the menu command PLC > Module Information. 2. Select the "Stacks" tab in the next dialog box.