SST Automation GT200-PN-RS, Руководство пользователя

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MODBUS slave protocol and Self-defined protocol
The two protocols are slave protocols. Their IO status word is used to indicate the running state of the protocol
by a 16-bit integer change. Every time a correct request frame is received from the slave. The value is
automatically added 1.
The 16-bit integer is represented in a Little-endian, where the low address represents the low byte of the 16-bit
integer and the high address represents the high byte of the 16-bit integer
3.3.1.11 Response Timeout Handling for Master Protocol
The specific application scene is like this: After the master sends the request frame, it will wait for the response
of the slave device within the limited time. If the slave does not respond within a limited time, the master
protocol will trigger the response timeout processing. How to deal with this?
If the command is successfully executed the previous time, it will be reissued three times (a total of four times),
In the process of retransmission, if any response is given from the slave, it will stop repeating and transferred to
the next command. If the slave still has no response after three retransmission, the processing method given in
the response timeout handling option is executed. Namely: Clear or Hold. It should be noted that the clear or hold
here is for the data part of the slave response frame. Because GT200-PN-RS transformation between protocols is
achieved by mapping, so the data part of each command's response frame will have a mapping area in the input
buffer of GT200-PN-RS.Our "clear or hold" is for this mapped data area. Specifically, if "clear" is selected, all
data in the map area will be set to 0 after the response timeout; if " hold", the content of the map data area will
not be changed after the response timeout.
If the command is unsuccessfully executed the previous time, re-transmission is not executed.
3.3.2 Self-defined Protocol
3.3.2.1 Definition
User device acts as initiator, send output data in the request frame.
GT200-PN-RS acts as responder which sends input data in the response frame.
Communication way is point to point.
Time interval between bytes in request frame should be less than 50ms, or GT200-PN-RS will dispose this frame
data.
For every valid request frame, GT200-PN-RS should make response in 200ms.
Supports communication baud rate range 300~115200 bps, 8 data bits, parity (None, Odd, Even, Mark, Space)