Fuji Electric FRENIC MEGA G2 Series - Page 69

2.2 Wiring
2-31
INSTALLATION AND WIRING
Chap 2
Table 2.2-9 Description of control circuit terminal functions (cont.)
Classification
Terminal
symbol
Terminal
command
Function description
Analog input
[V2]
PTC/NTC
thermistor
input
(PTC/NTC
function)
(1) PTC (Positive Temperature Coefficient)/NTC (Negative Temperature Coefficient)
thermistors for motor protection can be connected. SW5 (see “2.2.7 Switching switches”)
on the PCB must be switched to the PTC/NTC side.
The following diagram shows the internal circuit when SW5 (terminal [V2] changeover
switch) is switched to the PTC/NTC side. Refer to “2.2.7 Switching switches” for details
on SW5. When SW5 is switched to the PTC/NTC side, function code H26 also needs to
be changed.
Fig. 2.2-14 Internal circuit when SW5 is switched to PTC/NTC side
[11]
Analog
common
The terminal is the common terminal for analog input signals (terminals [13], [12], [C1], [V2],
[FM1], and [FM2]). The terminal is insulated from terminals [CM], [CMY].
• Use shielded wire and keep the wiring to the minimum as possible (below 20 meters) for control signals
which are susceptible to external noise. Grounding the shielded wire is generally recommended, but if
external induction noise is large, connecting to terminal [11] may reduce the noise. As shown in Fig. 2.2-15
below, shielded wire increases the shielding effect, and therefore one end must be grounded.
• When inserting a relay contact at analog input signal lines, use the twin contacts relay for small signals.
Also, do not insert a relay to terminal [11].
• When external analog signal generators are connected, the analog signal generator circuit may malfunction
due to the noise created by the inverter. In these cases, connect ferrite core (toroidal shape or equivalent)
to the output terminals of the analog signal generator or connect high frequency capacitors between the
control signal lines, as shown in Fig. 2.2-16 below.
• Do not apply a voltage of +7.5 VDC or higher to terminal [C1]. Failure to observe this could result in internal
circuit damage.
Fig. 2.2-15 Connection diagram for shielded wire
Fig. 2.2-16 Example of noise countermeasures
Variable
resistor
1 to 5 kΩ
Shield lines
<Control circuit
block>
<Control circuit
block>
<Analog signal
generator>
Pass through ferrite
core, wind 2 to 3
times as necessary
Capacitor
0.022 μF
50 V
Comparator