Indu-Sol PB-INspektor, Manual

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PB-INspektor
®
Quality Parameters
Page 19
This means that, when in doubt, you need to check every diagnostic message
in order to see if the message results from normal process behavior or from a
fault in the device.
6.3 Error telegrams
Even though the PROFIBUS is protected against possible transmission faults,
frames can nevertheless be falsified during physical data transfer. Frame
errors include, for example, character format errors, incorrect start and end
delimiters, frame check byte errors or incorrect frame lengths.
6.4 Retries
If a PROFIBUS device does not respond within a predefined time, or if the
master receives a frame containing information it cannot interpret, the master
requests the device concerned to retransmit the data. How often such a
request is transmitted per cycle depends on the retry limit set in the master.
When analyzing the PROFIBUS, the INspektor distinguishes between two
retry types:
x Max. Retries per Bus Cycle
x Total Retries
When determining the Max. Retries per Bus Cycle, the PROFIBUS INspektor
counts the maximum number of requests retransmitted to a device during a
bus cycle. When a device fails, the value displayed corresponds to the set
retry limit.
Under Total Retries, the INspektor determines the total count of all retrains-
missions that have occurred.
6.5 Bus Cycle Time
In a PROFIBUS DP V0 network (cyclic operation), all PROFIBUS devices are
addressed once per bus cycle. The time it takes the master to complete a
cycle is called the bus cycle time. When the PROFIBUS network is operating
properly, the bus cycle time is nearly always constant. If faults occur on the
network, the cycle time will vary increasingly. The PROFIBUS INspektor
measures these deviations and indicates the results under Bus Cycle Time
Min/Mean/Max. This helps you to detect faults on the network at an early
stage.
Web Interface Manual
Page 20
7 Web Interface
7.1 Startup Page/Overview
Fig. 7: Startup page of the web interface
On the left, you see the navigation area. With the two icons below it, you can
toggle between the English and German interface languages.
The measuring location is given at the top of the screen. This is particularly
useful when you are using multiple INspektors to monitor the network.
The actual workspace is provided under Overview. It is divided into the Events
and PROFIBUS Devices boxes.