Operating Instructions

Chapter 2—Hardware Features
TX-I/O Product Range Overview
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Siemens Industry, Inc.
Owner's Manual
588-781
Building Technologies
2018-10-01
TX-I/O Power Supply Overview
The TX-I/O Power Supply bridges communication and power from one DIN rail to
another and generates 28.8 W (1.2A at 24 Vdc) to power TX-I/O modules and
peripheral devices.
● An LED provides an indication of 24 Vdc on the TX-I/O bus.
● Up to 4 TX-I/O Power Supplies can be operated in parallel, with a maximum of two
per DIN rail.
● It can be located within a row of TX-I/O modules or at the beginning of a new DIN
rail.
The TX-I/O Power Supply performs the following functions:
● Transfers 24 Vac at 4A to power TX-I/O modules and peripheral devices.
● Provides an input point for 24 Vac to power additional peripheral devices.
– Isolates the 24 Vac peripheral device supply in case of overload or short-circuit.
– The replaceable AC fuse can be accessed from an installed module.
– Indicates the AC fuse status with an LED for easy diagnostics.
● Routes the bus signal between DIN rails (+24 Vdc Communication Supply (CS)
and Communication Data (CD) signals).
Supply Terminal Connections
● 24 Vac supply terminals are fused (replaceable) for Class 2 (24 Vac at 50/60 Hz)
through the TX-I/O Power Supply.
● 24 Vdc supply terminals are connected in the I/O module, not in the terminal base.
24 Vdc is supplied and overload protected in the TX-I/O Power Supply.
Bus Connection Module Overview
The Bus Connection Module bridges communication and power from one DIN rail to
another. It provides the bus signal, module supply voltage, and field device supply
voltage to TX-I/O Modules on an additional DIN rail.
The Bus Connection Module performs the following functions:
● Passes 24 Vac at 4A to power TX-I/O modules and peripheral devices.
● Provides an input point for 24 Vac to power additional peripheral devices.
– Isolates the 24 Vac peripheral device supply in case of overload or short-circuit.
– The replaceable AC fuse can be accessed from an installed module.
– Indicates the AC fuse status with an LED for easy diagnostics.
● 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.