The cycle time per device
PROFINET devices send data on a very periodic basis, these are called cycle times. Cycle times are defined in milliseconds.
Positive and negative message jitter as a percentage of the cycle time
Jitter is the deviation of a message from the intended cycle time. Example: if a device sends a message every 4ms, then a delay of an additional 4ms leads to a jitter of 100%. In case the message is 1ms early then a jitter of 25% is being reported. Both messages which are early and late are reported in absolute percentages.
The number of Dropped Packets
Dropped packets are PROFINET messages which were missing in the communication cycle. Healthy PROFINET networks should never drop messages, too many consecutive dropped packets can cause the stop of the network.
The number of Alarms
PROFINET alarms are specific error messages sent by the controller or the devices using the PROFINET protocol.