Samba™
PLC+ HMI Installation Guide
10
Unitronics
Earthing the PLC+HMI
To maximize system performance, avoid electromagnetic interference by:
Mounting the controller on a metal panel.
Connect each common and ground connection directly to the earth ground of your system.
For ground wiring uses the shortest and thickest possible wire.
Communication Port
Turn off power before making communications connections.
Caution
Always use the appropriate port adapters.
SM43/SM70-J-TA22
This series comprises a USB port.
Caution
The USB port in SM43 Series is not isolated. Make sure that the PC and the controller
are grounded to same potential.
The USB port may be used for programming, OS download and PC access.
SM35-J-TA22
This series comprises a build-in RS232 port.
Caution
Signals are related to the co
ntroller’s 0V; the same 0V is used by the power supply.
The serial port is not isolated. If the controller is used with a non-isolated external device,
avoid potential voltage that exceeds ± 10V.
Use RS232 to download programs from a PC, and to communicate with serial devices and
applications, such as SCADA.
Pinouts
The pinouts below show the PLC port signals.
RS232
Pin #
Description
1
Not connected
2
0V reference
3
TXD signal
4
RXD signal
5
0V reference
6
Not connected
Opening the Controller
Before performing these actions, touch a grounded object to discharge any electrostatic charge.
Avoid touching the PCB board directly. Hold the PCB board by its connectors.
1. Turn off the power supply, disconnects, and dismounts the controller.
2. The back cover of the controller comprises 4 screws, located in the corners.
Remove the screws, and pull off the back cover.
