ENMET MX-48 - Manual (Page 10)

ENMET Corporation MX48 C ONTROL
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W ARNING : Each channel of the MX48 C ONTROL has a terminal strip to which all wiring for that channel is
connected. A typical four-channel circuit board is shown in Figure 3a and wiring for this terminal is
shown in Table 3.
3.2.3 4-20 Sensor/Transmitter
Sensor/Transmitters are connected to positions C1, C2 and C3 on each channel terminal strip. Connections are shown
in Table 1 for two wire S/T and Table 2 for three wire S/T. See Figure 3a for location of channel terminal strips.
Table 1: Wiring for a Two Wire S/T Table 2: Wiring for a Three Wire S/T
Two Wire Sensor/Transmitter Three wire Sensor/Transmitter
C1 Signal minus (– – – –) C1 Signal
C2 Not used C2 Ground
C3 Signal plus, +24 V DC power C3 +24 V DC power
4-20mA Output Signal
The (+ 4/20 -) positions in each channel terminal is the 4-20mA output from the Control. The plus and minus sides of
the loop are indicated on the terminal strip. See Figure 3a and Table 3.
3.2.4 Relay Contacts
Auxiliary alarms should be powered from an independent power source separate form the instrument power to avoid
alarm failure due to controller malfunction.
MX48 C ONTROL relay contacts for the first two alarm levels are on the RL, 1, RL and 2 (reference # 6 – 9) positions
of each channel terminal strip, as indicated in Figure 3a and Table 3. There are 3-pin headers located to the right of the
channel terminals for setting relays to normally open or normally closed operation. To set relays place jumpers in the
position indicated in Figure 3a. These relays have a maximum capacity of 2 Amp at 230 Volts, and are programmed
as described in Section 5.
The system alarm relay contacts AL3 are on the power supply board, as shown in Figure 3.
3.2.5 Wiring Requirements
Sensor/Transmitters: Wiring to the Sensor/Transmitters should be by two or three wire shielded cable. The
recommended cable is 18 gauge three wire, ENMET part number 66017-006, Alpha-1747C or
equivalent.
Output Loop: Wiring to output loop should be similar two wire shielded cable.
Relay: Relay wiring can be suitable insulated wire.
Table 3: Typical Channel terminal strip connections
Reference: # Labeled Connection
1 C1 Signal
2 C2 Ground
3 C3 +24 V DC
4 + +4-20mA output
5 – –4-20mA output (Ground)
6 RL Alarm 1 relay
7 1 Alarm 1 relay
8 RL Alarm 2 relay
9 2 Alarm 2 relay