User Manual

Interconnection

The P-bus connection of the link incorporates an internal DC power supply for 128 load

units, to supply the power for the DESIGO I/O modules. The DESIGO I/O modules are

connected via the P-bus connection using the P-bus coupling module (I/O bar type PTX

1.01). The main supply voltage is derived from a separate AC 24 V transformer.

The PTX1.01 module can supply up to 18 I/O modules. If there are more than 18 I/O

modules, additional supply modules are required.

As described in data sheets CM2M8102 and CM2N8022 a double-insulated safety

transformer to EN 61 558, designed for continuous operation, must be used. At least

conductor G must be protected with a fuse. The transformer must be sized for the

effective load of the equipment in the control panel including the connected field

devices.

For separate control panel construction, please observe grounding precautions (as

described in CM2M8102).

To avoid earth loops, only G0 must be earthed to a central point. The earthing

precautions for the P-bus must be observed (see data sheets CM2M8102 and

CM2N8022).

For load distribution purposes, the G0 connection of the P-bus coupling module (I/O

bar, type PTX1.01) must be connected to G0 of the transformer. The G0 connection

(between PU and PC) of the DP/P-bus link is designed for connection of the P-

bus/remote bus. The remote bus has not yet been released.

Note

230V~

P-bus

coupling

module

PTX1.01

DP/ P-bus link

Profibus

(9-pin DSUB, RS485)

Ground

G G0 PU G0 PC PD

24V~

* Parallel connection of G0

(Terminal 2)

for connection of remote bus

not yet released.

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Siemens Building Technologies DP/P-bus link CK1N9871en

Building Automation 23.04.2003