Hach Polymetron 9500 Benutzerhandbuch Seite 15

powered controller and 24 VDC, 5A resistive maximum for the DC powered controller. The relays are
not rated for inductive loads.
Wiring relays
Potential Electrocution Hazard. Always disconnect power to the instrument when making electrical connections.
Potential fire hazard. The relay contacts are rated 5A and are not fused. External loads connected to the relays
must have current limiting devices provided to limit current to < 5 A.
Potential fire hazard. Do not daisy-chain the common relay connections or jumper wire from the mains power
connection inside the instrument.
Potential electrocution hazard. In order to maintain the NEMA/IP environmental ratings of the enclosure, use only
conduit fittings and cable glands rated for at least NEMA 4X/IP66 to route cables in to the instrument.
AC line (100—250 V) powered controllers
Potential electrocution hazard. AC mains powered controllers (115 V–230 V) are designed for relay connections
to AC mains circuits (i.e. voltages greater than 16 V-RMS, 22.6 V-PEAK or 35 VDC).
The wiring compartment is not designed for voltage connections in excess of 250 VAC.
24 VDC powered controllers
Potential electrocution hazard. 24 V powered controllers are designed for relay connections to low voltage circuits
(i.e. voltages less than 16 V-RMS, 22.6 V-PEAK or 35 VDC).
The 24 VDC controller relays are designed for connection to LOW voltage circuits (i.e., voltages less
than 30 V-RMS, 42.2 V-PEAK or 60 VDC). The wiring compartment is not designed for voltage
connections above these levels.
The relay connector accepts 18-12 AWG wire (as determined by load application). Wire gauge less
than 18 AWG is not recommended.
The Normally Open (NO) and Common (COM) relay contacts will be connected when an alarm or
other condition is active. The Normally Closed (NC) and Common relay contacts will be connected
when an alarm or other condition is inactive (unless the Fail Safe is set to Yes) or when power is
removed from the controller.
Most relay connections use either the NO and COM terminals or the NC and COM terminals. The
numbered installation steps show connection to the NO and COM terminals.
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