Emerson 2400S installation manual 2.6Wiring the power supply

Transmitter Orientation and Power Supply

2.5.1DC power requirements for Model 2400S Analog and PROFIBUS-DP transmitters

If you are using DC power with a Model 2400S Analog or PROFIBUS-DP transmitter, the following requirements apply:

•At startup, the transmitter power source must provide a minimum of 1 A of short-term current per transmitter.

•Length and conductor diameter of the power cable must be sized to provide 18 VDC minimum at the power terminals, at a load current of 0.5 A. To size the cable, refer to Table 2-2and use the following formula as a guideline:

MinimumSupplyVoltage = 18V + (CableResistance ⋅ CableLength ⋅ 0.5A)

Table 2-2Typical power cable resistances at 68 °F (20 °C)

Gauge	Resistance(1)
14 AWG	0.0050	Ω/foot
16 AWG	0.0080	Ω/foot
18 AWG	0.0128	Ω/foot
20 AWG	0.0204	Ω/foot
2,5 mm2	0,0136	Ω/meter
1,5 mm2	0,0228	Ω/meter
1 mm2	0,0340	Ω/meter
0,75 mm2	0,0460	Ω/meter
0,5 mm2	0,0680	Ω/meter

(1) These values include the resistance of both high and low conductors in a cable.

Example The transmitter is mounted 350 feet from a DC power supply. If you want to use

16 AWG cable, calculate the required voltage at the DC power supply as follows:

MinimumSupplyVoltage = 18V + (CableResistance ⋅ CableLength ⋅ 0.5A)

MinimumSupplyVoltage = 18V + (0.0080 Ohms/ft ⋅ 350 ft ⋅ 0.5A)

MinimumSupplyVoltage = 19.4V

2.6Wiring the power supply

Note: This procedure is required only for Model 2400S Analog and PROFIBUS-DP transmitters. To wire the power supply:

1.Remove the transmitter housing cover and user interface module as described in Section 2.4.

2.Unscrew the warning flap screw and raise the warning flap. Figure 2-3shows the warning flap in the open position.

3.Connect the power supply wires to terminals 9 and 10, as shown in Figure 2-3.

4.Ground the power supply to the transmitter’s internal grounding screw, shown in Figure 2-3.

5.Lower the warning flap and tighten the warning flap screw.

8 Micro Motion® Model 2400S Transmitters