Transformer Selection Powering Devices and Wiring • 15
5 Powering Devices and
Wiring
5.1. Transformer Selection
The power supply voltage for iPro Case Controller, XEV20D; and
IPX is 24VAC. The Visograph remote display is powered from
the remote display port on the iPro. Emerson provides a variety of
24VAC non-center tapped transformers that can be used to power
these devices. Transformer requirements are a minimum of 20VA
for the iPro Case Controller and the iPro must not share a
transformer with any other devices. The transformer power
requirements of the IPX106D are a minimum of 10VA and
requirements for the XEV20D are a minimum of 40VA. Each
device must have its own dedicated transformer.
5.2. Wire Types and Maximum
Distance
For powering iPro, XEV20D and IPX106D use only the listed
wire types in Table 5-2. Two conductor non-shielded cables are
the recommended wire for connecting each of the devices to the
secondary of the transformer. Shielded cable should not be used
for power wiring. The center tap should be left disconnected, if
present on the transformer.
The wire length from the transformer determines the wire gauge
used. In most cases, the distance between the iPro Case Controller
and the transformer that supplies power to it is not enough to be
of concern; however, it is very important NOT to exceed this
maximum wire length or the controller will not operate correctly.
Use these formulas to determine if the wire gauge you are using
fits within specification:
5.3. Wire Selection Guidelines
5.4. Powering the iPro Case
Controller
The iPro can be powered from one of the transformers listed in the
Table 5-1 and Figure 5-1 shows how to connect the 24VAC
wiring from the transformer to the iPro connector. The 24VAC
power is connected to terminals 1 and 9 on the analog input
connector. The iPro should have its own dedicated transformer for
providing the 24VAC needed for supply power.
Transformer Part
Number
Primary Voltage VA Rating
640-0040 120/208-240VAC 50 VA
640-0041 120 VAC 50 VA
640-0042 220 VAC 50 VA
Table 5-1 - Transformer Selection
Power Wire Types
14 AWG Belden 9495
18 AWG Belden 9495
Table 5-2 - Power Wire Types
14 AWG:
Feet = 1920/VA
18 AWG:
Feet = 739/VA
(VA is the total VA rating of the controller)
For example, if you had an 80 VA load:
14 AWG: 24 ft.
18 AWG: 9 ft. (rounded down)
Table 5-3 - Power Wire Lengths
DEVICE TYPE EMERSON
WIRING GUIDELINES
ANALOG TEMP
SENSOR OR DIGITAL
INPUT
General Cable 92454A #22-2
SHIELDED
Emerson P/N 135-0600
RS485 NETWORK General Cable 92454A #22-2
SHIELDED
Emerson P/N 135-0600
PRESSURE
TRANSDUCERS
**BELDEN #8771 #22-3 SHIELDED
Emerson P/N 135-8771
**#8771 for alternate 600v rated wire
use BELDEN #8618 16 AWG
STEPPER VALVES Use valve manufacturer’s harness
with a maximum length not to
exceed 30 feet (10 meters).
Table 5-4 - Wiring Specifications
NOTE: Neither side of the secondary should be
connected to ground. Also, do not connect the center
tap (if provided on the transformer) to ground. The
entire secondary of the transformer should be
isolated from any ground.
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