Hill-Rom Advanta P1600, Service Manual

Page: 182 / 429

ZoneAire® Sleep Surface Software Theory of Operation
Chapter 3: Theory of Operation
Page 3 - 44 Advanta™ Bed Service Manual (man168ra)
Continuous Run Error
In all modes, except the off mode, the system is monitored for the following
failure conditions that would cause the pump to run continuously:
• Excessive air leaks
• Faulty pump
• Faulty air manifold or flow direction valve
• Faulty pressure sensor or sensor circuit
• Faulty control circuit
• Loss of AC power or blown fuse
• Open or pinched hose
• Mattress connector not seated properly
If the pump runs continuously for approximately 10 min, in either an inflate or
deflate sequence, a continuous run error is flagged, the operating mode
transitions to off, and the footboard control panel service required LED
repeatedly flashes code 2, 2.
Triac Short Error
In all modes, except the off mode, the system is repeatedly checked for a
control circuit failure that would cause an air manifold valve, the flow
direction valve, or the pump to be wrongly activated.
Whenever the system is not correcting pressures, the feedbacks from the triac
drive circuits are monitored. If any feedback indicates an activated drive circuit
continuously for 5 seconds, a triac short error is flagged, the operating mode
transitions to off, and the footboard control panel service required LED
repeatedly flashes code 2, 3.
EEPROM Error
Upon reset and during power up (transition from the off mode to pressure relief
mode), the calibrations read from the pressure sensing circuit EEPROM are
checked for validity. Each calibration constant is stored in four locations to aid
in determining whether there is an error. The circuit also detects faulty
readings due to shorted or open communication lines between the control
circuit and the pressure sensing circuit.