46
Ref. 185040646 MR730/720/700/480 Technical Manual ¯ Revision F ¯ Issued March 2001
The data record as received should start with an ‘:’ and end with an ‘LF’. Under abnormal operating conditions however
(when there are ‘E’ messages in the display) some or all of the above packets ‘a’ to ‘g’ can be missing. The status
information packet ‘h’ will always be present (as long as the micro is running) and will show the error condition.
When there are error messages in the display, bit 6 of the last status byte will be set high indicating a fatal error
condition.
First Byte
Bit0 Probe disconnect LED
Bit1 Heater Wire disconnect LED
Bit2 Airway Temp Low LED
Bit3 Airway Temp High LED
Bit4 Chamber Temp Low LED
Bit5 Chamber Temp High LED
Bit6 Chamber Temp Button LED
Bit7 Always set high
Second Byte
Bit0 Standby button LED
Bit1 Heater Wire operation LED
Bit2 Remote Shut Down request acknowledge
Bit3 Set Low LED
Bit4 Audio alarm muted
Bit5 External request acknowledge Heater Wire operation
Bit6 External request acknowledge No Heater Wire operation
Bit7 Always set high
Third Byte
Bit0 Heaterplate ON
Bit1 Heater Wire ON
Bit2 Always low
Bit3 Always low Bit4 Bit5 Model
Bit4 See table 00MR480
Bit5 See table 10MR700
Bit6 Fatal error 01MR720
Bit7 Always set high 11MR730
A5.3 REMOTE STANDBY
A constant high input (pin 2 DB9 connector >1.5 V) shuts down the humidifier. Low or open circuit input enables the humidifier. An RSD request signal puts the humidifier into
the standby mode; i.e. No low alarms active, controlled 40.0 °C heaterplate and 15% Heater Wire duty cycle. On removal of an RSD request the humidifier enters the warm up
mode. On the MR730/720 models the standby LED is also turned on (not flashing).