Profinet module

Introduction

PROFINET is an open Industrial Ethernet communication protocol, based on international standards. It is designed to exchange data between controllers and devices, mostly in manufacturing and/or automation environments. Since its introduction in the early 2000s, it has grown to become the most well-adopted Industrial Ethernet solution.

Allegro Network Multimeter facilitates highly granular PROFINET monitoring and PROFINET troubleshooting in real-time and back in time. Packet-based analysis and statistics are available for communication relations, top talkers, bandwidth consumption, jitter, frames, PROFINET errors and alarms (PN-RT, PN-RTA and PNIO-CM).

Allegro Packet’s incident engine allows for automatic reporting of PROFINET alarms and threshold based triggers to e-mail and syslog. Also PROFINET traffic recording and automated event-based PROFINET packet capturing is readily available to you in Allegro Network Multimeter.

Overview

The overview page (1^st tab) is the global information dashboard revolving PROFINET traffic.

These include graphs and tables depict:

• PROFINET traffic VS total traffic
• Global PROFINET PN-RT errors
• Millisecond micro burst analysis
• Global PROFINET jitter
• The top 5 senders and receivers

Whenever graphs depict anomalies such as high loads, RT-errors and/or high jitter...these instances can be zoomed into by selecting (click 'n drag) a spike in the graph with the mouse.

The top talker tables are sortable by IP, byte or frame count. The download button at the end of each device line, provides you with a pre-filtered pcap, containing only the conversations from that specific IP/MAC during the selected time interval. Both forward capturing in real-time as well as retroactive packet extraction from an active ring buffer are possible.

Global stats

The global stats page (2^nd tab) provides you with detailed statistics and a summary for a specific/selected time interval.

The (time interval) information listed on this page includes:

• Total PROFINET bytes and frames count
• Total PROFINET alarms and errors count
• Average and maximum PROFINET jitter
• PROFINET unanswered request count
• PROFINET unrequested response count
• PROFINET response time information

Whenever graphs depict anomalies such as high loads, RT-errors, alarms and/or high jitter...these instances can be zoomed into by selecting a spike in the graph with the mouse (click 'n drag). This not only helps narrow down the timeframe to troubleshoot, it also results in the most optimized pre-filtered pcap files with PROFINET traffic, if those are needed.

Devices

The global devices page (3^rd tab) lists all seen PROFINET devices or controllers. You can sort all data and statistics displayed in the columns, for instance to quickly find the device with the highest jitter, the most errors, alarms or most traffic.

Whenever graphs depict anomalies such as high loads, RT-errors, alarms and/or high jitter...these instances can be zoomed into by selecting a spike in the graph with the mouse (click 'n drag). This not only helps narrow down the timeframe to troubleshoot, it also results in the most optimized pre-filtered pcap files with PROFINET traffic per MAC/IP, if those are needed. The download buttons on the far right, provides you with such a pre-filtered pcap. I will only contain the conversations from that specific IP/MAC during the selected time interval. Both forward capturing in real-time as well as retroactive packet extraction from an active ring buffer are possible.

When clicking on a MAC or IP address of a PROFINET device in the address table, a very detailed summary page for that particular device is shown. The resulting page will be further explained below.

Communication relations

This tab shows all communication relations of the device. All communication relations are listed where the device took part either as sender or receiver.

Profinet Real-Time (PN-RT)

This tab lists all cyclic RT frames and groups them by frame ID. An error field lists the number all errors extracted from the data and transfer status of every frame. Based on the cycle counter, a loss detection, repeated frames or whenever the cycle counter moves backwards is indicated.

Alarms (PN-RTA)

This tab lists all Alarms (high and low priority).

DCP

This tab lists all DCP (Discovery and Configuration Protocol) frames that were sent from or sent to this device. DCP is used to configure station names and IP addresses.

PTCP

This tab lists all PTCP (Precision Transparent Clock Protocol) frames that were sent from or sent to this device. PTCP is used for time synchronisation.

Profinet over UDP

This tab lists all acyclic CM (Context Manager) frames that where sent over UDP from or to this device. The protocol is used during startup for creation of application and communication relations and allows for acyclic write and read requests between two Profinet devices.

Jitter

For cyclic frames a jitter calculation is performed. The calculation is based on the increment of the cycle counter of two subsequent frames and the timestamps of both two frames as seen by the Multimeter. An error field shows the number of all responses with an error status, the number of not answered requests and the number of responses without a request.

Response times

For acyclic requests in the scope of CM (Context Manager) times are measured between a request and a response (as seen by the Multimeter).