Manual
ibaFOB-D
38
Issue 1.11
Figure 24: Simulation of the bandwidth distribution in a 32Mbit Flex telegram
The data sizes in bytes of each device on the link and the timebase of the data acquisition
on the link (in µs) is needed for the calculation.
The values can be manually entered or taken automatically from the current configura-
tion, either with a click on the button <Estimate values from current configuration> or
when the respective link of the ibaFOB board is marked in the module tree.
The devices in the Flex ring and the corresponding data sizes are listed in the grid on
the left. Address 0 corresponds to the Ethernet channel and is not editable.
The section “Flex frame utilization” indicates how much of the bandwidth is still available.
The color of the section changes with the utilization rate:
Green: OK
Orange: bandwidth for the Ethernet channel < 3 kB/s
Red: too much data.
The values taken automatically are initially estimated. When the configuration is applied
by a click on <OK> or <Apply> the actual data sizes are shown on the “Info” tab.
When too much data are configured, you may either decrease the number of signals to
be measured or increase the timebase.
Simulation of the load
Even if no devices have been connected and configured, the calculation of the telegram
size can be used for calculating the expected data load in advance. However, an
ibaFOB-D or ibaFOB-io-ExpressBoard board should be available in the computer.
Open the I/O Manager in ibaPDA, click on the link of the board and select the "Configu-
ration" tab.
Set the smallest planned sampling time in the "Timebase" field. Now, you can enter man-
ually the planned or expected data amount (in Bytes) in the table rows 1 to 15. With every
new entry, the result values in the "Flex frame utilization" field are re-calculated.
In this way, you can estimate if the planned number of signals can be processed on one
Flex link or if you should use an additional Flex link.
