Performance Test
The results of the test should give an indication of the relationship of the PLC cycle time to the employed hardware. This may be helpful when selecting the necessary hardware.
 | The test took place under optimum conditions in a test environment specially set up for the purpose. Therefore, the results obtained cannot be carried over to other environments without restriction. |
Structure
A read command was transmitted on a 16-bit value for one minute with PLC cycle times of 50, 10 and 1 millisecond. The Beckhoff PLC was thereby the reading device. The number of successfully transmitted read commands was recorded by a counter. This produced the following results:
Results
Device description | PLC cycle time | Value description | ||
50ms | 10ms | 1ms | ||
| ||||
IPC Windows XP (Pentium M at 1.8 MHz) | 0 | 0 | 0 | Error |
299 | 1180 | 3785 | Read commands | |
299 | 1180 | 3785 | Successful read commands | |
| ||||
CX1020 Windows XP V1.37a | 0 | 0 | 0 | Error |
298 | 1208 | 4208 | Read commands | |
298 | 1208 | 4208 | Successful read commands | |
| ||||
CX1010 Image V HMI 2.18 | 0 | 0 | 0 | Error |
298 | 1078 | 2709 | Read commands | |
298 | 1078 | 2709 | Successful read commands | |
| ||||
CX9001 Image V HMI 2.20e | 0 | 0 | 0 | Error |
299 | 997 | 1928 | Read commands | |
299 | 997 | 1928 | Successful read commands | |
The test shows that reducing the PLC cycle time significantly increases the number of read commands. The higher the PLC cycle time is, the smaller the influence of the hardware capability on the data transfer rate.
Select the hardware such that the PLC cycle time can be set as low as possible. The performance can also be improved using an additional, faster background task in which communication with the Crestron controller is executed.
| The TwinCAT System Manager offers aids for optimizing the PLC cycle time. Further information on this can be found in the documentation for the TwinCAT System Manager. |
