Edwards STP-iX455 User Manual

STP-iX455/iXL455 Series Instruction Manual
9-9
Operation
9.3 Protocol Specifications
9.3.1 General Description
The STP serial communication protocol enables the SIM to receive the communication
command transmitted from the PC and sends a response following the communication
command. Each communication command from the PC transmits a text message (ASCII
text) assigned to each function. Communication commands include control commands
(STP pump operation commands, etc.) and query commands (read-out of STP pump
operation mode, etc.).
Table 9.5 shows ASCII characters being used in the transmission control, error control
and handshake in the application layer. Note that the transmission frame form differs
depending upon the RS232/RS485 single point connection and RS485 multi-point
connection (see Section 9.3.8, "Transmission Frame in the RS485 Multi-point
Connection").
Table 9.5 Transmission Control Characters
ASCII
character
HEX
code
Function
Transmission layer
Stx 02 Transmission block start character
Etx 03 Transmission frame end character
Etb 17 Transmission block end character
Ack 06 Acknowledgment response
Nak 15 Non-acknowledgment response
@ 40 Network frame ID character
Application layer
# 23 Acknowledgment response
! 21 Non-acknowledgment response
9.3.2 Standard Transmission Frame (in the RS232/RS485 Single Point Connection)
The transmission frame used in the RS232/RS485 single point connection has a single
block or multiple transmission blocks. The transmission block consists of a start control
character, data block No. (3 digits), a message (up to 255 characters), an end control
character, and a checksum (LRC). The following table shows the transmission frame
where the message transmission character string is C
n
.
Transmission frame when a message is below 255 characters (n<=255):
1 2 3 4 5 5+n 5+n+1 5+n+2
ASCII Stx 0 0 1 C
1
C
n
Etx LRC
"Stx" and "Etx" are used as a start and an end character of the transmission frame,
respectively.
PC
SIM
(Control unit)
(1) Communication command
(2) Response

Edwards STP-iX455 Specifications

General

Brand	Edwards
Model	STP-iX455
Category	Water Pump
Language	English