Protocol Specifications; General Description - Edwards STP Series Instruction Manual

5.3

Protocol specifications

5.3.1

General description

In the STP serial communication protocol, a SIM(s) receives communication commands transmitted
from a PC (Figure 39-1), and sends a response following the communication commands (Figure 39-
2). The communication commands from a PC transmit a text message (ASCII text) assigned to each
function. The communication commands include the control commands (the STP pump operation
commands) and the query commands (read-out of the STP pump operation modes).
1. Communication command
Table 20 shows ASCII characters used in the transmission procedures, error procedures, and
handshake in the application layer.
Transmission layer
Application layer
STP-iXA4507 series Turbomolecular Pump
1
2
Figure 39 - PC to SIM communication
ASCII HEX
character code
Stx 02
Etx 03
Etb 17
Ack 06
Nak 15
@ 40
# 23
! 21
Table 20 - Transmission control characters
2. Response
Function
Transmission block start character
Transmission frame end character
Transmission block end character
Acknowledgment response
Non-acknowledgment response
Network frame ID character
Acknowledgment response
Non-acknowledgment response
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