User's Manual

Elpro Technologies 450U-E Wireless Ethernet Modem & Device Server User Manual
58 www.cooperbussmann.com/wirelessresources Rev Version 1.4.0
startup.
Beacon Interval
Shows the Beacon Interval configure on the AP
SSID
Shows the Access Points SSID
Throughput Testing 4.2
Radio Throughput
There are a number of throughput estimations that may help to determine the amount of data that can be successfully
transmitted through the modems. These throughput estimations are based on perfect radio conditions, i.e. little to no
outside radio interference present while data is being passed and they are calculated using real life conditions and
communication constraints.
The performance of a wireless link is best measured in terms of the maximum throughput that can be achieved. The
recommended methods for measuring modem throughput are to use an external Modbus Client to poll the internal
Modbus Server on the remote modem or to use a FTP Server/Client arrangement and transfer a file, measuring the time it
takes to send. It is recommended that the throughput tests be performed on point to point link with minimal radio
interference, i.e. no communications from other wireless network traffic.
Modbus TCP.
Below is a table showing the maximum number of polls per minute (ppm) based on the radio receiver signal level.
Results show two different test polls using two different data speeds and with and without Data Compression. For more
details on what data compression is and how to implement it, read section 3.7 Data Compression
The test is designed to simulate a Modbus TCP Client polling a Modbus TCP server through the radio modems utilising
the two different data rates (2 Level FSK and 4 Level FSK) and scanning a different number of I/O points.
Setup for the Modbus Client was made to simulate the fastest polling rate possible and then determine the number of
messages that were successfully polled in a one minute period. TCP Client scan rate was 5msec, poll delay was 5msec
and the Slave response time was 10seconds.
Typical results for this setup are shown below.
Data Throughput Modbus (Polls per Minute)
4800 baud (2 level FSK)
9600 baud (4 Level FSK)
20 Words @ maximum Scan rate No Compression
72 Ppm
91 Ppm
20 Words @ maximum Scan rate With Compression
89 Ppm
113 Ppm
120 Words @ maximum Scan rate No Compression
50 Ppm
58 Ppm
120 Words @ maximum Scan rate With Compression
89 Ppm
113 Ppm
FTP Transfer
Another means for gauging the data throughput performance of the modem is to transfer a known data file using FTP (File
Transfer Protocol) and time how long it takes for the file to download.
l need to run an FTP server
application, i.e. Fillzilla, Cerberus Server, etc and the other as an FTP client. Because the 450U-E has a reduced
throughput compared with other Ethernet modems you will need to adjust the connection timeout under the settings
within the application. Below are some estimated throughputs for ftp transfer using different radio baud rates.
Note: the results will vary depending on the type of file that is being sent and if Compression is
enabled or not.
Data Throughput FTP (file transfer)
4800 baud (2 level FSK)
9600 baud (4 Level FSK)
100k text file No Compression
294sec @ 0.34kB/s
185sec @ 0.72kB/s
100k text file With Compression
65sec @ 1.54kB/s
46sec @ 2.17kB/s
134k jpg file No Compression
404sec @ 0.33kB/s
185sec @ 0.72kB/s
134k jpg file With Compression
215sec @ 0.62kB/s
183sec @ 0.73kB/s