Emerson E2 operation manual IMC/Prodigy Rooftop Unit Controllers, Board Installation, Wiring Types

Unit	Amps	VA	VAC	Center-
				tapped?
16AI	0.25	5.0	24	Yes
8RO/SMT	0.75	15.0	24	Yes
4AO	0.5	10.0	24	Yes
8DO	1.5	18	24	Yes
8IO/ARTC	0.75	18	24	No
IRLDS	N/A	N/A	120/240	N/A
RLDS	N/A	N/A	120/240	N/A
MultiFlex	3.3	80	24	Yes
ESR
MultiFlex	0.25	6	24	Yes
16
MultiFlex	0.75	15	24	No
88, 88AO,
168, and
168AO
MultiFlex	1.0	20	24	No
1616L,
1616LAO,
1616LDO

Table 6-3- Device Power Requirements

To select a power transformer for a board or a series of boards:

1.Determine what the total VA is for the boards that will be powered by the transformer (see Table 6-3).

Example: Two MultiFlex 168AOs (15 VA each), and one 8DO (18 VA) boards are to be powered by one transformer. The total VA is:

(2 × 15VA ) + (1 × 18VA ) = 48VA

2.Use a transformer that has a power rating higher than the total calculated VA (see Table 6-2).

Example: For boards totalling 48VA, a 56VA trans- former is sufficient, since 56VA is greater than 48VA.

I/O Board Transformers should be located within 10 feet of the board it is powering, preferably within the board enclosure.

6.1.9.1Wiring Types

For powering I/O boards, use only the listed wire types from Table 6-4. Three-conductor non-shielded cables are the recommended wire for connecting between the center tapped transformer and the I/O boards. The third conduc- tor should be connected to earth ground. If boards use a

center-tapped transformer, also connect the center tap to the earth grounded third conductor.

Power Wiring Types

14 AWG	Belden 9495
18 AWG	Belden 9493

Table 6-4- Power Wiring Types

The wire length from the transformer and the number of boards connected to the same wire determines the type wire gauge used. In most cases, the distance between the I/ O boards and the transformer that supplies power to them is not enough to be concerned with. But it is very impor- tant not exceed this maximum wire length or the boards will malfunction.

Use these formulas to determine if the wire gauge you are using fits within specification:

14 AWG:

Feet = 1920/VA

18AWG: Feet = 739/VA

(VA is the total VA rating of the I/O boards) For example, if you had an 80 VA load:

14AWG: 24 ft

18AWG: 9 ft (rounded down)

Figure 6-3- Power Wire Lengths

Sensors requiring 24VAC can be powered from the same transformer powering the input board as long as the resulting total load of both the input board(s) and the sen- sor(s) connected to the transformer does not exceed the transformer’s VA rating. Consult Section 6.1.9, Powering the I/O Boards, and Section 8.6.1, Powering Echelon Devices for more information.

6.1.10 Board Installation

The following pages give step-by-step graphical instructions on all steps necessary to install each I/O Net- work device so that it is powered up and able to communi- cate with E2. If these devices have not yet been mounted, refer to Section 3.2, Mounting I/O Boards for mounting instructions for these devices.

6.2IMC/Prodigy Rooftop Unit Controllers

All E2 Building Controller (BX) versions 2.21F01 and

IMC/Prodigy Rooftop Unit Controllers The RS485 Network and Hardware Setup • 6-5