Oldham MX48 - DC Power Supply; Detectors (Figure 12); Explosimetric Detectors of PONT Type; 3-Wire Detectors 4-20 Ma: 3 Connecting Wires for Shielded Cable

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2.2.2. DC power supply
- Voltage: 21 to 30 V continue. The "-" from continue power supply is linked to
earth (and earth being linked to frame).
- Maximum power: 150 W
- Maximum current in cable: 6.3 A
- Cable: 2 x 2.5 mm²
- Location of terminal block: see Fig. 8, item D
- Protection: by two fuses located at the back of the power module (Fig. 3)
2.3. Detectors (Figure 12)
REMARK
- The detectors are linked by SHIELDED cables.
- The utilization of shielded cables is MANDATORY
- The earth braid of shielded cables must be connected to the earth at one end
only.
CAUTION
Each channel is configured in the factory for a given type of detector (explosive gas, toxic
gas, fire or flame). If two different types of detector are interchanged, this may result in
the destruction of the central unit or of the detector.
2.3.1. Explosimetric detectors of PONT type
Three connecting wires for a shielded cable.
Resistance of detector / unit cable: 16 ohms maximum per wire, i.e. 32 ohms in loop (1 km for cable
3 x 1.5 mm²).
Connection on MX48 unit: see Fig. 10 – Example 1
2.3.2. 3-wire detectors 4-20 mA: 3 connecting wires for shielded cable
- Resistance of detector / unit cable: 16 ohms maximum per wire, i.e. 32 ohms in loop
(1 km for cable 3 x 1.5 mm²).
- Connection on MX48 unit: see Fig. 10. – Example 2