Communication efficiency information – [MyConfig].prt

The installation report [MyConfig].prt

When you install an IGSS configuration, you get the option of viewing an installation report. You determine what you want to view in the report in the Installation Options dialogue shown below.

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PLC-related information

The installation report contains the following sections related to PLC communication:

The entire system configuration (setup of stations and drivers)
Objects sorted by PLC address
Objects sorted by scan class
(the Scan intervals chosen on the Data Management Definitions tab in the object properties dialog box)
PLC communication efficiency information

For further details about the installation report, click here.

The setup of stations and drivers

This section of the report shows the settings defined for all stations and drivers.

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Objects sorted by data group

This section contains a list of all objects for which a PLC address has been defined. The objects are sorted by data group. Notice that overlapping PLC addresses are marked with the word Overlap in the last column.

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Objects sorted by scan class

The scan classes section of the report shows a list of scan records divided into the four scan classes as shown below.

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PLC communication efficiency information

Towards the end of the report, information about PLC communication efficiency is provided. The system designer can use the efficiency figures found to optimize the use of the PLC memory area. For both the parameters below, i.e. "Number of bits used for objects" and "Total number of words in scan records", the aim is to get the efficiency percentage as close to 100 % as possible. This will result in the most effective and speediest communication between IGSS and the PLC.

The two efficiency percentages are calculated and used as follows:

Number of bits used for objects
The efficiency percentage is calculated as follows:

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The percentage expresses how effectively the bits used for IGSS objects have been packed within the data words read by IGSS. For example, if you're defining a digital object and only use the first two bits in a data word for two different digital states, the remaining bits of the data word are unused. Avoid unused bits by packing the word with digital states so that no bits remain unused.

Note: If this percentage is higher than 100 %, it means that some PLC addresses are not unique. In some cases, you can do this deliberately to save space in the PLC, but in other cases it may mean that relevant data is overwritten.

Total number of words in scan records
The efficiency percentage is calculated as follows:

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The percentage expresses how many relevant data words IGSS has read within a scan record. For example, if IGSS is reading 32 data words in one scan and only 25 of those are used for IGSS objects, the PLC addressing can be optimized. The closer you get to 100 %, the more efficient and faster the PLC address scanning takes place.

Closely related to these efficiency percentages is one of the key PLC design considerations. When you plan the use of the PLC memory area, make sure that IGSS objects with the same scan interval reside in the same data groups and words. This will reduce the number of scan records and thus optimize communication between IGSS and the PLC.

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