STP-iXA4507 series Turbomolecular Pump
SERIAL COMMUNICATION PROTOCOL
5.3.4 Query command (in the RS232/RS485 single point connection)
A query command is used to read the pump operation state and setting values. The first character of
the query command in the RS232/RS485 single point connection is "?" (HEX code "3F"), and the
subsequent characters are ASCII characters corresponding to the respective function code and
parameter.
CHR: Function code character, C
1
to C
n
: Parameter
The parameter (C
1
to C
n
) is a 16 bit signed hexadecimal value coded ASCII text. When a message
(the space character, the function code, and the parameter) exceeds 255 characters, input "?" 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 2nd and the subsequent transmission blocks.
The SIM returns the acknowledgement response character "#" when correctly processing the query
command. 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 with one block and returned with two blocks:
Designate the query command on a PC first.
The parameter characters are less than 254 characters (n< 254) when the message is less than 256
characters.
Then if the preceding SIM->PC character is "Ack", the instructed query command is executed, and
the SIM returns the following response (1st block).
And then, if "Ack" is sent by the PC->SIM character as a response (1st block) to the SIM, the SIM
returns the following response (2nd block).
The PC transmits "Ack" or "Nak"; then transmits the next command if necessary.
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