8100/8200 Monitor Instruction Manual
1.2.6 Alarm Relays
The alarm relays are internally configured for fail safe operation. When power is applied and the sensors are clear the
relays will be energised, on alarm the relays are de-energised. Each alarm has normally closed and normally open
contacts for external signalling, the normal condition is when the unit is powered and the alarm is off.
1.2.7 Fault Relay
The fault relay is utilised when there is a problem with the sensor or alternatively there may have been a power failure
to the system and in this instance the relay will be de-energised and therefore send the monitor into a fault state
1.3 Applications
The 8100 & 8200 Monitors, when combined with a compatible sensor, are designed for use as a sludge blanket level
detector, a sludge density switch, or as a suspended solids/turbidity switch. The 8100 & 8200 Monitors are therefore
suitable for interfacing with automatic de-sludging control of primary and secondary settlement tanks, thickener control
and high and low blanket level alarm, or as a simple alarm in a water/ waste water flow.
1.3.1 Sludge Blanket Level Detection
When used for this operation the monitor uses an IR or ST series sensor, which is suspended by its cable to the
desired monitoring depth in the tank. When the settled sludge reaches the sensor then the alarm output is activated.
This can then be used as an input to a process system to directly control pumps, bell mouths or simply to alert the
operator. The same principle can be used to monitor when the sludge reaches a minimum point when it is being
removed from the holding tank.
1.3.2 Suspended Solids Switch
The 8100/8200 Monitor can be used as a suspended solids switch when used in conjunction with the IR and ST series
sensors. The sensor can be installed in an effluent channel to detect a value of suspended solids and give a high
alarm.
168270IM-02 Issue Date 05/01/2010 Page 5 of 14
To Next Page
Loading...
Need help?
General
