User Manual
EM303B General Purpose Inverter
37
Connect to PC or PLC through RS485/RS232 converter
A-
EM303B
A+
PE
RS485/RS232
Converter
PC/PLC
232
Communication
Terminals
485+
485-
232+
232-
GND
GND
Figure 3-20 Wiring Communication Terminals
Remarks:
For the applications with severe electromagnetic noise, please ground the GND of
communication points to the common ground.
3.3.9
Size of Control Circuit Cable and Screw
To lower interference and attenuation of control signal, the cable length of control signal
should be in a maximum of 50m, and the distance should be in a minimum 30cm between the
signal cable and the power cable. Twisted-pair cable or shielded cable shall be used when
inputting analog signal externally. It shall be the best to take 0.5~1mm2 cable as the control
circuit cable.
There are two types of control circuit wiring terminals for EM303B: clamp terminal and
barrier terminal, please install them with a PH0 cross head screwdriver with a tightening
torque of 0.5N.m. Please pay attention to followings based on different features of these two
terminals:
Clamp terminal
Take pin terminal or cable strip length by 5~7mm for connection.
Only after the terminal screw is fully loosened anticlockwise first, the cable can be
inserted.
Barrier terminal
Take a circular or a U-sharp clamp terminal with holes of 3.5mm.
3.3.10
Precautions for Wiring Control Circuit
1.
Separate the control circuit cable from the other cables.
2.
Separate the cable of control circuit terminals EA, EB, EC, Y1, and Y2 from the cables of
other control circuit terminals.
3.
Use shielded twisted-pair cables for control circuit to avoid malfunctions caused by
interference. The wiring distance should be in a maximum of 50m.
4.
Wrap the shield net with insulating tape to prevent the shield net from contacting with
other signal cables and housing of device.