Hach SC4200c Manual Básico Del Usuario página 18

Potential fire hazard. Do not daisy-chain the common relay connections or jumper wire
from the mains power connection inside the instrument.
Explosion hazard. This manual is only for installation of the unit in a non-hazardous
location. For installation of the unit in hazardous locations, use only the instructions and
approved control drawing provided in the hazardous location installation manual.
Fire hazard. Relay loads must be resistive. Always limit current to the relays with an
external fuse or breaker. Obey the relay ratings in the Specifications section.
Make sure that the cable sheath goes through the inner side of the enclosure to keep the
environmental rating of the enclosure.
The instrument has two non-powered relays, each with a single-pole change-over contact. Each
relay changes state when the selected trigger condition for the relay occurs.
The relay terminals are located behind a high-voltage barrier in the controller enclosure. Do not
remove the barrier while power is supplied to the relay terminals. Do not supply power to the relay
terminals when the barrier is not installed.
Connect each relay to a control device or an alarm device as necessary. Refer to
Table 4 to connect the relays. Use the MSM software to configure the trigger condition for each relay.
Refer to Specifications
and the low-voltage input/output circuitry.
The relay terminals accept 0.75 to 2.5 mm
Use wire with an insulation rating of 300 VAC or higher. Insert each wire into the appropriate terminal
until the insulation is seated against the connector with no bare wire exposed. Tug gently after
insertion to make sure that there is a secure connection. If necessary, remove the connector from the
PCBA for easier wiring of the terminals. Flexible wires must have a crimped ferrule or a pin type
terminal on the end.
Note: Make sure that all of the cables stay below the cable limit line printed on the PCBA to prevent interferences
with the high-voltage barrier.
The current to the relay contacts must be 5 A (resistive only load), 1250 VA 125 W (resistive only
load) or less. Make sure to have a second switch available to remove power from the relays locally in
case of an emergency or for maintenance.
Use the relays at high voltage (greater than 30 V-RMS and 42.2 V-PEAK or 60 VDC) only. The
maximum switching voltage is 250 VAC. Do not configure a combination of both high and low
voltage.
Relay terminal connections to the mains circuit in permanent connection applications must have
insulation rated for a minimum of 300 V, 70 °C (158 °F). Terminals connected to the mains circuit
with a power cord connection must be double insulated and rated 300 V, 70 °C (158 °F) at both the
inner and outer insulation levels.
18 English
W A R N I N G
W A R N I N G
C A U T I O N
N O T I C E
on page 3 for the relay specifications. The relays are isolated from each other
2
(18 to 12 AWG) wire (as determined by load application).
Figure 10 and