Welch Allyn LC101 CO2 Module - User Manual - Manual (Page 41)

LC101 CO
2
Module OEM Implementation Manual Section 4 - Host/Module Communications
Welch Allyn OEM Technologies Confidential Page 41
Software Protocol
Packets
• Module must respond within 1 second after receiving a host command (50 msec
typical response time).
• There is no minimum time interval between packets.
• Host must request Module status periodically to confirm the fault/OK status of the
Module and sensor.
• Host must either receive a Module response or have exceeded the Module response
timeout of 1 second before issuing a new command.
• There are no restrictions when switching from mode to mode.
• A packet that interrupts another packet causes the interrupted packet to be ignored.
• An incomplete or incorrectly formatted packet is ignored.
• Status messages have identical meanings in all operating modes.
Faults
WARNING The host should not assume that the Module is faultless if CO
2
waveform and
breath data is being sent. Data response packets may be communicated when
the Module is in a non-fatal fault, or soft fault state.
• If a fault occurs and the host issues a new mode command that is different from the
current mode, the Module responds with either a hard fault status and ignores the
mode command, or retries by attempting to clear the fault.
• If the Module is in a soft fault state, the host should issue a new measurement mode
command to attempt to clear the fault.
• A fault condition may leave the Module in the fault mode indicated by a status
response. For , yy is the status message and z is the other status.
Module Resets
External Resets (Initiated by the Host System)
• Software Reset - The host may command a software reset using the
command while the Module is unprotected. After the reset, the Module returns to its
EEPROM default settings.
• Reset - If the host holds the receive data line in a break condition for greater than 10
msec, but less than 500 msec, the microprocessor is forced into reset. After the reset,
the Module returns to its EEPROM default settings and starts up in the standby mode.
The Module can respond to host communication 2 seconds after a reset.