© Munters AB, 2018 7
2 Precautions
•
Grounding
•
Checking the Battery Level
•
Filtering
•
Frequency Inverters
2.1 Grounding
•
Always connect temperature and sensor shields to earth ground.
Avoid mixing high voltage
wiring with sensor and low voltage wiring
.
•
Keep the controller as far as possible from heavy contactor boxes and other sources of
electrical interference
.
•
Do not connect communication wire shields, which go from one house to another at both
ends. Connect them at one end only. Connection at both ends can cause ground loop
currents to flow, which reduce reliability
.
•
The COM connection for communications is not the shield wire. The COM, RX and TX wires
must connect to each other at all controllers
.
2.2 Checking the Battery Level
Check the battery once a year. The output must be 2.7 volts (minimum). Authorized personnel only must
replace the battery if the output is below the minimum required level or every five years.
2.3 Filtering
If this installation includes a power inverter to drive variable speed fans, install an EMI filter in front of
the inverter, according to the specifications provided by the inverter manufacturer. Refer to the inverter
documentation.
2.4 Frequency Inverters
Frequency inverters can cause severe electrical and electromagnetic interference. Therefore, when
employing a frequency inverter, it is critical that you carefully follow the manufacturer's installation
instructions.
In particular, verify:
•
that the cable shielding between the inverter and any motor meets industry standards
•
proper grounding of the inverter's chassis and motor power cable
•
proper grounding of low voltage cable shield wire
•
that the controller and inverter cables are kept in separate conduits or wire bundles
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