Installation Instructions

Chapter 5 - Control Unit
Control Cable Sizing
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Siemens Industry, Inc.
Smart Infrastructure
Siemens BT300 HVAC Drive
Installation Instructions
DPD01148
2019-05-29
measurements of the main circuit (for example, DC-link voltage, unit temperature)
are not available when line voltage is not connected.
Control Cable Sizing
The control cables shall be at least 0.5 mm
2
(30 AWG) screened multi-core cables,
see the table in the Power Cabling section. The maximum terminal wire size is 2.5
mm
2
(14 AWG) for the relay and other terminals.
The following table outlines the tightening torques of the control and relay board
terminals.
Table 19: Control Cable Tightening Torques.
Terminal Screw
Tightening Torque
Nm
lb-in.
All I/O and relay terminals (screw M3)
0.5
4.5
Control Terminals and DIP Switches
The basic control unit connections are presented in the following figure. The
control board is equipped with 22 fixed control I/O terminals and the relay board
with 8 or 9. The relay board is available in two different configurations.
The terminals of the Basic I/O board and the Relay boards are described below. For
more information on the connections, see the following figure.
The terminals shown on shadowed background are assigned for signals with
optional functions selectable with DIP switches. See more information in the
Selecting Terminal Functions and Isolating Digital Inputs from Ground with DIP
Switches section.