Selecting The Activation State Of The Relay; Figure 40 Relay Module - Vaisala DRYCAP DMT340 Series User Manual

Chapter 3 _______________________________________________________________ Installation
WARNING
WARNING
VAISALA _______________________________________________________________________ 61

Selecting the Activation State of the Relay

The middlemost C terminal and either one of the terminals NO/NC shall
be connected. The polarity can be freely selected.
NO Normally open
C Common relay
NC Normally closed
Relay NOT activated:
Relay IS activated:
Connect the power and close the cover. For instructions on how to
operate the relay (for example, select quantity for the relay output and set
the relay setpoints) see section Operation of Relays on page 120.
Figure 40 Relay Module
Numbers refer to Figure 40 above:
1 = Indication led for the relay 1 or 3
2 = Relay test buttons
3 = Flat cable pins
4 = Indication led for relay 2 or 4
The relay module may contain dangerous voltages even if the
transmitter power has been disconnected. Before working on the relay
module you must switch off both the transmitter and the voltage
connected to the relay terminals.
Do not connect the mains power to relay unit without grounding the
transmitter.
C and NC outputs are closed, NO is open
C and NO outputs are closed, NC is open.
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