Glossary
S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF
505
Cycle control point
The cycle control point marks the end of a cycle and the start of the next cycle. The cycle time
statistics and monitoring of the configured maximum cycle time start at the cycle control
point.
Once the cycle control point has been reached, the CPU writes the process image output to
the output modules, reads the state of the inputs in the input modules and then executes the
first program cycle OB.
The following requirements must be met for reaching the cycle control point in redundant
mode:
• the primary CPU has reached the end of the cyclic program
• the backup CPU has reached the end of the cyclic program and reported this to the
primary CPU
• if a minimum cycle time was configured, this is removed
Cycle time
The cycle time is the time a CPU requires to execute the cyclic user program once.
Cyclic interrupt
You can find more information in the "Interrupt, cyclic" glossary entry.
Data block
Data blocks (DBs) are data areas in the user program that contain user data. Available data
blocks:
• Global data blocks that you can access from all code blocks.
• Instance data blocks that are assigned to a specific FB call.
Device
A device can send, receive or amplify data via the bus, e.g. IO device via PROFINET IO.
Device names
Each IO device must have a unique device name. This is required to allow the IO controller to
communicate with an IO device. Advantage: Device names are easier to manage than
complex IP addresses.
In its delivery state, an IO device has no device name. A device name must be assigned using
the PG/PC before an IO device can be addressed by an IO controller. Example: For
transmission of the configuration data (e.g. the IP address) during startup or for exchanging
user data in cyclic mode.
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