Welch Allyn Duet CO2 Module - User Manual - Manual (Page 28)

Duet CO
2
Module OEM Implementation Manual
Page 28 Confidential Welch Allyn OEM Technologies
The data format options are 7 or 8 bits. (Defaults to 7 bit.)
The module start up mode options are auto run, measurement, warm standby, standby and fault.
(Defaults to sidestream fault mode.)
The initial pump flow rate option allows the host to specify desired default flow rate. (Defaults to
175ml/min.)
Refer to the System EEPROM Map Table in Appendix A Software Procedures for further information.
Packet Communication
Transmission of host commands and module responses is via packets. The following byte structure
represents a packet.
Packet format:
< start of text (STX) 02h
X identifier 1*(ASCII)
xx
n
data n(hex char)
yy CCITT/CRC code 2*(ASCII)
> end of text (ETX) 03h
ASCII characters have values in the range of 00h to 7Fh. The identifier is case sensitive. Characters
between 00h and 20h are reserved as control characters.
Transmission of all packets starts with a “<” STX control character and ends with a CCITT/CRC code
and “>” ETX control character. Between STX and ETX is an identifier and n bytes of ASCII data. The
length of the packet is defined by the identifier character. Packet length cannot exceed 25 bytes with a
maximum of 20 bytes of data allowed. Packets without the STX control character are ignored. The
CRC code is computed on values between STX and CRC code.
02h X xx
n
yy 03h
Host Commands
The host communicates to the module via commands. These include
§ mode commands, to request a change in the operating mode.
§ simple commands, to request data or a status change. Data is not sent with these commands.
§ configuration commands, to specify custom system settings. Data is sent with these
commands.