Wiring Precautions - Mitsubishi Electric FR-A800 Instruction Manual

Common terminals of the control circuit (SD, PC, 5, SE)
• Terminals SD (sink logic), PC (source logic), 5, and SE are common terminals (0V) for I/O signals. (All common terminals
are isolated from each other.) Do not earth (ground) these terminals. Avoid connecting the terminal SD (sink logic) with 5,
the terminal PC (source logic) with 5, and the terminal SE with 5.
• In the sink logic, terminal SD is a common terminal for the contact input terminals (STF, STR, STP (STOP), RH, RM, RL,
JOG, RT, MRS, RES, AU, CS) and the pulse train output terminal (FM
internal control circuit by photocoupler.
• In the source logic, terminal PC is a common terminal for the contact input terminals (STF, STR, STP (STOP), RH, RM, RL,
JOG, RT, MRS, RES, AU, CS). The open collector circuit is isolated from the internal control circuit by photocoupler.
• Terminal 5 is a common terminal for the frequency setting terminals (2, 1 or 4) and the analog output terminals (AM, CA
It should be protected from external noise using a shielded or twisted cable.
• Terminal SE is a common terminal for the open collector output terminals (RUN, SU, OL, IPF, FU). The contact input circuit
is isolated from the internal control circuit by photocoupler.

Terminal FM is provided in the FM-type inverter.

Terminal CA is provided in the CA-type inverter.
Signal inputs by contactless switches
The contact input terminals of the inverter (STF, STR, STP (STOP), RH, RM, RL, JOG, RT, MRS, RES, AU, CS) can be
controlled using a transistor instead of a contact switch as shown below.
External signal input using transistor
(sink logic)
2.6.4

Wiring precautions

• It is recommended to use a cable of 0.3 to 0.75 mm
• The wiring length should be 30 m (200 m for the terminal FM) at the maximum.
• Use two or more parallel micro-signal contacts or twin contacts to prevent contact
faults when using contact inputs since the control circuit input signals are micro-
currents.
• To suppress EMI, use shielded or twisted cables for the control circuit terminals
and run them away from the main and power circuits (including the 200 V relay
sequence circuit). For the cables connected to the control circuit terminals, connect their shields to the common terminal of
the connected control circuit terminal. When connecting an external power supply to the terminal PC, however, connect the
shield of the power supply cable to the negative side of the external power supply. Do not directly earth (ground) the shield
to the enclosure, etc.
• Always apply a voltage to the fault output terminals (A1, B1, C1, A2, B2, C2) via a relay coil, lamp, etc.
+24V
STF, etc
Inverter
SD
2
for the connection to the control circuit terminals.
). The open collector circuit is isolated from the

Inverter
PC
STF, etc
External signal input using transistor
(source logic)
Micro signal contacts
INSTALLATION AND WIRING
Control circuit
).

+24V
R
Twin contacts
39
2