Welch Allyn Duet CO2 Module - User Manual - Manual (Page 47)

Duet CO
2
Module OEM Implementation Manual
Welch Allyn OEM Technologies Confidential Page 47
Pneumatic Operation
Introduction
The Duet Module Sidestream Pneumatic System, or Pneumatic System, is responsible for controlling
the flow to the sidestream bench in order to measure patient CO
2
level. The Pneumatic System must
set the flow as commanded by the host and keep it within flow specifications. Conditions such as
inlet/exhaust irregularities, internal pneumatic disconnects and pump failures are detected by the
Pneumatic System.
NOTE All user message handling and recovery procedures for pneumatic events, disconnects of
internal pneumatics and pump failures are the responsibility of the Host system.
The Duet Module and the host system are referred to as the “Module” and “host” in the remainder of
this section.
Normal Flow
Normal flow is controlled by the pneumatic system to remain within +15/-20% of the set flow rate. The
host can set a flow rate between 90ml/min and 200 ml/min using the Change Pump Flow
Rate command. The Module responds to a requested flow rate that either exceeds or is less than the
flow limits with a Invalid Data response.
The host can expect stable pump operation during normal flow conditions without additional
intervention. However, the host must poll the Module periodically to determine the status.
WARNING The host should NOT assume that the module is faultless if CO
2
waveform and breath
data is being sent.
Pneumatic Events
Pneumatic events that may occur include
§ total inlet occlusion § barometric pressure out of range
§ partial inlet occlusion §
unexpected reverse flow
§ total exhaust occlusion § unexpected forward flow
§ partial exhaust occlusion