STP-iXA4507 series Turbomolecular Pump
SERIAL COMMUNICATION PROTOCOL
5.3.9 Control command in RS485 multi-point connection
The control command to a SIM for a pump operation or a setting change transmitted is specified
below. The first character is "Sp" (space character, HEX code "20"). And the next ASCII characters
correspond to the function code and parameter.
CHR: Function code character, C
1
to C
n
: Parameter
The parameter (C
1
to C
n
) is 16 bit signed hexadecimal value coded ASCII text. When a message (the
space character, the function code, and the parameter) exceeds 255 characters, input "Sp" and CHR
to only the top of the transmission blocks (the first transmission block of the transmission frame). It is
unnecessary to input them into the second and succeeding transmission blocks.
The SIM returns the acknowledgement response character "#" when the control command is
processed correctly. If not, the SIM returns the non-acknowledgement response character "!" and 3
characters of the non-acknowledgement code are added to "!".
Transmission frame when data is transmitted to one block (a message is less than 256 characters):
Designate the control command on a PC first.
Parameter characters are less than 254 characters (n< 254) when a message is less than 256
characters.
Then the preceding SIM->PC character is "Ack", the instructed control command is executed, and
the SIM returns the following response.
The PC transmits "Ack" or "Nak"; then transmits the next command if necessary.
Transmission frame when data is transmitted to two blocks (message is more than 256 characters
and less than 512 characters):
Designate the control command (the 1st block) on a PC first.
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