Time Delay of RS485 datastream and analog output?

The program execution time (cycle time) is automatically adjusted based on the program complexity (Auto-Tuning). The automatic adjustment affects the data exchange via Modbus since program execution takes higher priority over processing requests. If the program is very extensive, it can consume the entire CPU time, and the Modbus data exchange will not be carried out correctly.

To avoid this issue, a lower limit is reserved for the volume of Modbus data exchange: 50 requests per second. This means that at least 50 requests per second can be executed, even if the user program is large, and even more if the program is small and the processor performance is sufficient. If there is not enough time to query all devices, the number of queries in the user program should be optimized.

The setting of the polling cycle depends on the number of variables queried and the polling frequency in the program. It is recommended to set the polling cycle to 1 second. In this case, the device can query up to 50 variables.

The minimum processing time of the program cycle is 1ms, and the signal conversion time for analog outputs is 100ms.