TXB1.PBUS

What is this module used for in a building automation panel?

It acts as the interface between an automation station with a P-bus interface and a TX-I/O module island, enabling communication to the connected I/O modules and distributing power within the island (e.g., via the TXB1.PBUS).

Which bus connections does the module provide?

It provides connections for P-bus communication (PC, PD, PU) and for island bus communication (CS, CD, system ground).

What supply voltage does the module require?

The module is powered by AC 24 V extra-low voltage (SELV/PELV), 50 to 60 Hz, with an input tolerance of -10% to +20%.

Does it provide power for connected modules and field devices?

Yes. It incorporates a regulated DC 24 V output (CS to system ground) to supply TX-I/O modules and connected field devices, and it also provides an AC 24 V output for field supply.

What are the output current ratings?

The DC 24 V output is rated up to 1.2 A and is overload protected and short-circuit proof. The AC 24 V field output supports up to 6.0 A and is protected by a replaceable medium time-lag 10 A fuse.

Can the DC 24 V module supply be expanded with additional power supplies?

Yes. The integrated DC 24 V supply can be operated in parallel with up to three external power supply modules of the same system family, provided the overall island design remains within permitted limits.

How is the module mounted in a control panel?

It mounts on a standard 35 mm top-hat DIN rail (TH35-7.5). Within a TX-I/O bar, the first device on the left side is typically a power-supplying device such as this bus interface module.

Can it be installed in any orientation?

Yes, it can be mounted in any orientation, but adequate ventilation is required to maintain permissible operating temperatures.

What do the front LEDs indicate?

Typical indications include: RUN (CPU in operation), FLT (fault and status conditions, including missing configuration), COM (P-bus communication activity), plus separate indicators for AC 24 V field/supply availability and for the DC 24 V module supply on CS.

What is the purpose of the USB port on the front?

The USB Type-B port is intended for local commissioning and diagnostic access using an appropriate engineering tool. The interface operates at USB Full Speed (12 Mbit/s) and is not galvanically isolated from system ground.

What cabling and terminal sizes are supported?

The plug-in screw terminals accept solid or stranded copper conductors from 0.25 to 2.5 mm² (or two conductors up to 1.5 mm², depending on the wiring arrangement). Maximum tightening torque is 0.6 Nm.

What are the typical environmental and enclosure characteristics?

Typical operating ambient temperature is -5 to +50 °C with 5 to 95% relative humidity (non-condensing). The front-plate components in a DIN cut-out are typically rated to IP30, while the terminal section is typically IP20.

What are the approximate dimensions and weight for panel planning?

The housing is DIN 43880 format and approximately 90 mm wide. Overall dimensions are approximately 128.3 mm (height) x 70 mm (depth), and the unit weighs about 280 g without packaging (about 318 g packaged).

Are the communication lines protected against short circuits?

The island bus (CS, CD) and P-bus (PC, PD, PU) communication interfaces are designed to be short-circuit proof; however, the side bus connector is not protected against short circuits, so careful handling during installation is important.