In Modbus communication systems, we can imagine polling time and timeout as interactions between instructors and soldiers. The polling time is like an instructor checking the intervals between soldiers.
For example, the instructor may check the condition of the soldiers every 10 minutes, just like the main station (instructor) would "inquire" (poll) about the condition of the subordinate stations (soldiers) at regular intervals. The timeout is like the patience of an instructor waiting for a soldier's response. For example, when an instructor asks a soldier a question, he may give the soldier 5 seconds to answer. If the soldier does not respond within these 5 seconds, the instructor may assume that the soldier did not hear his question and will ask again. This is like the master sending a request to the slave, then waiting for a response from the slave. If no response is received within the timeout period, the master will send the request again.
From a professional perspective, polling time refers to the frequency at which the master station sends requests to the slave stations. It determines how often the master station sends requests to the slave stations. The timeout is the longest time that the master station waits for a response from the slave station. If the master station does not receive a response from the slave station within this time, the master station will consider the request failed and send it again. The setting of polling time and timeout time needs to be adjusted according to the actual system requirements and situation.
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