Operating Instructions

Chapter 2—Hardware Features
PX Series Enclosures and Service Boxes
0
90
| 118
Siemens Industry, Inc.
Owner's Manual
553-104
Building Technologies
2018-10-01
● Routes the bus signal between DIN rails (+24 Vdc Communication Supply (CS)
and Communication Data (CD) signals).
Supply Terminal Connections
● 24 Vdc is supplied to terminals one and four (CS) and to both ends of the TX-I/O
bus connector for distribution to connected TX-I/O modules and external devices.
● 24 Vac is passed through an internal fuse from terminals three and four (system
neutral) to the male TX-I/O bus connector.
● External devices draw power from the 24 Vdc, 24 Vac, and system neutral
terminals on the TX-I/O modules.
● 24 Vdc supply terminals are connected in the I/O module, not in the terminal base.
24 Vdc is current-limited in the Bus Connection Module.
PX Series Enclosures and Service Boxes
PX Series enclosures house both electronic and pneumatic components. The
enclosures include a perforated backplane for mounting PXC Series field panels or
other electronic or pneumatic components.
General features of the enclosures include:
● Availability in three sizes to match installation needs: 18-, 19-, and 34-inch.
● Sturdy construction, which accommodates secure conduit fittings and protects
components against incidental contact and falling dirt.
● UL Smoke Control listed for indoor use (19- and 34-inch enclosures only).
● Multiple knockouts along the top and bottom.
● Perforated backplane, which extends wall-to-wall for mounting of additional
equipment.
● Spacious interior for easy routing and termination of wiring.
The 18-inch enclosure is a pull-box type utility cabinet for low cost installations. It is
equipped with the following:
● Factory-installed 16” × 12” perforated panel
● DIN rail and wire tie bar kit
The 19- or 34-inch PX series enclosures are equipped with the following:
● Factory-installed backplane assembly, which includes wire tie down rails and DIN
rails
● Label pouch
● Hinged door and key lock
● Conduit knockouts and venting
PX Series Service Box Features
The PX Series Service Box Assemblies transform either 115 Vac or 230 Vac to 24 Vac
sized for either 192 VA or 384 VA.
● The 192 VA service boxes mount directly inside a 19- or 34-inch PX Series
Enclosure.
● The 384 VA service boxes provide additional power for larger systems and mount
only in the 34-inch PX Series Enclosure.
The service boxes provide protection against electrical transients and are Smoke
Control and Energy Management listed when installed according to the
Service Box
Assemblies Installation Instructions
(553-131).