Siemens S7 Driver Tag Type Properties: Serial Tab
The Serial tab for the Siemens S7 driver tag properties folder consists of attributes used to identify and establish a connection to the control device to be associated with this driver.
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Since the only protocol currently available is ISO over TCP, you should configure and select a TCP Port.
A half second time out limit with one retry is recommended as a reasonable value for a Siemens PLC.
In the event of an interruption in communication, this option will cause the last good value to be held. You should use this option with caution since, unless there is another means to alert you to interruptions in communication, it will appear that a valid value is still being received.
Timeout period, after which a lack of protocol traffic is considered an error. Default: 30 seconds.
Maximum PG/OP packet length used for initial communication with the PLC. This value will not be used after length negotiation with the PLC is complete. Default: 240.
Defines the maximum number of PG/OP packets that may be outstanding. Default: 1 outstanding request.
Defines the maximum number of item addresses to include in a request. Default: 18 items.
Defines the maximum number of requests that can be sent in one semaphore acquisition. Default: 100 requests.
Defines the maximum amount of time to hold the semaphore. Default: 1 second.