ANALOX Sub Mk III F, User Manual

Page: 47 / 79

Sub MkIIIF
User Manual
Int. Approved
Document ref: ASF3-800-08 November 2018 Page 47 of 79
Copyright © 2009 Analox Ltd. All Rights Reserved.
Commercial in Confidence
7.5 Oxygen Injection System
The Injection module is designed to operate a solenoid valve to control the flow of oxygen to the
area being controlled. If the measured oxygen value is greater than the injection set-point, then
no action is taken by the instrument.
Two modes of operation are possible. The system may operate as a %Oxygen controller or as a
partial pressure oxygen controller. Two LED indicators show which mode, if any, is operating.
If the measured value of oxygen falls below the Injection set-point, then the solenoid valve is
activated and oxygen is injected for a time period proportional to the difference between the set-
point and the measured value. On completion of the injection period, the module allows a Pre-set
Mixing Period of
x seconds to permit mixing of the recently injected oxygen.
Opening times for the injection valve are stored within the Remote Sensors configuration memory
in an EEROM based Lookup table. It should not be necessary to adjust these after fairly simple
commissioning tests. If the times do need to be changed, contact Analox for advice.
Mixing Time is essentially determined by the size of the chamber and the positioning of injection
points within the chamber. After the Mixing period, a further check is made of the oxygen
concentration to determine if the solenoid valve should be re-opened.
When the oxygen level is above the set-point, no injection is required. The mixing period is
therefore not required. The unit will wait for the oxygen level to fall to a value at which further
injection is required and then immediately perform an injection cycle.
The LED indicators on the REM3 Injection unit have the following significance:
LED INDICATOR SIGNIFICANCE
OFF Injection is currently disabled
ON Injection is currently enabled, but the injection
solenoid is not currently open (Mixing Time)
Flashing Injection is currently enabled, and the
injection solenoid is currently open.
RED ON Injection is enabled but cannot occur due to a
fault. These faults are:
The occurrence of all fatal faults.
The occurrence of under-range / over-range
faults on the O2 sensor or pressure sensors
The occurrence of calibration faults on the O2
or pressure sensors.
It is highly dangerous to use an oxygen control system without an independent monitoring system.
It is not envisaged that anyone will use an Analox oxygen controller in the absence of another
monitoring system, whether that be supplied by Analox or anyone else.