Operating instructions

Charged Aerosol Detectors
Corona Veo and Corona Veo RS
Page 72 Operating Instructions
5.7.4 Flow Ratio Alarm
The detector continuously monitors the internal pressure. On the Diagnostics screen, the
flow ratio diagnostic provides detailed pressure information for internal components. If a
"low" or "high" flow ratio alarm is triggered, the following actions occur:
• An error code appears on the detector display.
• The detector will exit the Run mode. If you operate the detector from chromatography
software, the running batch is aborted.
• If the Pump Off relay has been connected, the pump will stop mobile phase flow.
• Corona Veo RS: The stream-switching valve will actuate and divert the liquid flow away
from the detector.
• The drain pump will turn on automatically.
Tip: When you operate the detector from a chromatography data system, an error
message will also be documented in the audit trail of the software.
For more information on how to resolve a flow ratio alarm state, see the 'Troubleshooting'
section (→ section 7, page 91).
5.7.5 Detector Flooding Alarm
If the detector is properly connected to a pump in a LC system as described in section 3.4.4
(→ page 31), the system can receive a contact closure from the detector in the event of a
critical error.
Tip: Most LC pumps are programmed to send out a general contact closure in the
event of a low pump pressure alarm as determined in the configuration. Be sure
that this setting is compatible with the analytical method.
When the gas pressure falls outside of the specified range of 241 – 480 kPa (35 – 70 psi), the
following actions occur:
• An error code appears on the detector display.
• The detector will exit the Run mode. If you operate the detector from chromatography
software, the running batch is aborted.
• If the Pump Off relay has been connected, the pump will stop mobile phase flow.