Sensor Installation - Hach ORBISPHERE 51 Serie Manuel D'utilisation Simplifié

4.8.5 Measurement alarm relays
The three output relays are located on the measurement board.
They can be individually configured to Normally Open (NO) or to Normally Closed (NC) by
physically moving the jumper on each relay. The illustration is for the EC measurement
board (the positions are different for the TC measurement board):
• Upper relay is set to NC
• Middle relay is set to NO
• Lower relay is shown with no jumper
Note: For all measurement boards, J4 is relay 1, J5 is relay 2 and J6 is relay 3

4.9 Sensor installation

4.9.1 EC sensors
For EC sensor installation, servicing, and maintenance ensure you follow the instructions in the
Sensor Installation and Maintenance manual that was supplied with the instrument.
4.9.2 TC sensors
For TC sensor installation, servicing and maintenance ensure you follow the instructions in the TC
Sensor Installation and Maintenance manual that was supplied with the instrument. Pay particular
attention to the installation and connection of the purge gas supply.
Do not place the TC sensor into a liquid sample until a constant supply of dry purge gas has been connected, as
liquid could condense inside the measuring chamber and cause damage to the thermal conductor chip.
To ensure the continuation of purge gas while the sensor is in contact with the sample, it is highly
recommended to use a backup purge gas cylinder with an automatic changeover valve that activates
when the first cylinder is empty.
The use of an ORBISPHERE Model 29089 gas regulator (or similar) is also recommended to deliver
a constant, pressure regulated supply of dry purge gas to the sensor, filtered to 40 μm.
In addition, and to prevent any damage to the sensor electronics, the use of a purge safety backup
unit (ORBISPHERE Model 32605) is highly recommended to ensure the supply of purge gas remains
uninterrupted to the sensor in the event of a mains power outage.
The above ORBISPHERE accessories are explained in more detail in the TC Sensor Installation
and Maintenance manual.
Section 5 User interface
5.1 Instrument controls
The instrument front panel provides:
• A touch screen acting as display, touch pad and keyboard.
• A LED, showing when the instrument is on.
Turning instrument On and Off
The instrument portable versions have a power switch located on the back panel. There is no power
switch for the wall or panel instruments. The mains must be disconnected to turn the instrument off.
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