Dawn CONTROL-1500A Manual page 76

CONTROL-1500A Single Axis Antenna Controller
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Mnemonics
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STX
ETX
Checksum LRC byte
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States Description
State 1 (Slave Idle State). In State 1, a slave is ready to receive a new message, and
therefore, must complete any previous message reception. A slave always powers on in State
1.
A slave will exit State 1 and enter State 2 (Slave Addressed State) only if STX byte is received.
State 2 (Slave Addressed State). In State 2, a slave is waiting to receive the address byte, the
second byte of a command message.
A slave will exit State 2 and enter:
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Table 1. State Diagram Mnemonics
Start-of-Text ASCII control character, used as a header in command
messages to identify the beginning of a new message.
End-of-Text ASCII control character, used as a termination character in
messages to identify the end of data.
(Longitudinal Redundancy Check) is a last byte in the message data block. The value of
LRC byte is the exclusive OR of all message bytes including the STX and the ETX bytes
and is used to detect errors during transmission of data.
Appendix D The RCI RS422 Interface Spec
Description
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