Causes Of Wiring-Related Malfunction And Countermeasure Examples - Mitsubishi Electric GOT2000 Series User Manual

7.3.2

Causes of wiring-related malfunction and countermeasure examples

Causes of a malfunction due to grounding of the GOT include potential difference caused by grounding and noise.
The following measures may reduce potential difference and noise.
■1. Wiring of the ground cable and power line of the GOT
When the ground cable and power line of the GOT are installed together, the GOT may malfunction due to noise.
Separating the ground cable and power line of the GOT in wiring reduces the influence of noise.
LG
Good example: The ground and power cables
■2. When leading the ground cable from the control panel having control equipment into the
control panel having the GOT
When a single ground cable is led from the control panel having control equipment, including a PLC, into the control
panel having the GOT, the cable may be directly connected to the power terminal of the GOT.
The malfunction due to the potential difference caused by the grounding in such a case may be prevented by reducing
the voltage as shown in countermeasure example 1 below.
(1) Countermeasure example 1
When any potential difference between the ground cable and the control panel having the GOT affects the GOT, also
connect the ground cable to the control panel.
When Countermeasure example 1-1 is difficult to be taken, such as the wiring is impossible, carry out wiring as
shown in Countermeasure example 1-2.
Ground wires
Use as short
and thick a wire
as possible.
If noise further affects the GOT by taking Countermeasure example 1, Countermeasure example 2 may reduce the
influence of noise.
7 - 8
7.3 Grounding
GOT
FG
Power for the
power equipment
are separated in wiring.
Ground cable led from
the panel having
the control equipment
Measure example 1-1
Connection
cable
GOT
FG
LG
Grounding to
the panel
GOT
LG FG
Power for the
power equipment
Bad example: The ground and power cables
are installed together.
Connection
cable
GOT
FG
LG
Connection
cable
Ground wires
Measure example 1-2
GOT
FG
LG
Grounding to
the panel