Hitachi SJ7002 Series Instruction Manual page 184

Software Lock
Opt. Code
[SFT]
Symbol
Valid for
[1] to [8]
Inputs
Required
(excluded
Settings
from lock)
Default
Requires
terminal config.
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Switching to inverter control occurs after the motor is running at full speed. First, Mg2 relay
contacts open. Then about 0.5 to 1 seconds later, relay Mg3 contacts close, connecting the
inverter to the motor. The following timing diagram shows the event sequence:
Mg1
Mg2
Mg3
FW
Set to 0.5 to 1 sec. typical
[CS]
Inverter
output
In the previous timing diagram, when the motor has been started across the line, Mg2 is
switched OFF and Mg3 is switched ON. With the Forward command to the inverter already
ON, the [CS] terminal is switched ON and relay Mg1 contacts close. The inverter will then read
the motor RPM (frequency matching). When the [CS] terminal is switched OFF, the inverter
applies the Retry wait time before motor restart parameter (B003).
Once the delay time has elapsed the inverter will then start and match the frequency (if greater
than the threshold set by B007). If an over-current trip occurs during frequency matching,
extend the retry wait time B003. If the ground fault interrupter breaker (GFI) trips on a ground
fault, the bypass circuit will not operate the motor. When an inverter backup is required, take
the supply from the bypass circuit GFI. Use control relays for [FW], [RV], and [CS].
When the terminal [SFT] is ON, the data of all the parameters and functions (except the output
frequency, depending on the setting of B031) is locked (prohibited from editing). The keypad
15
and remote programming devices will be prevented from changing parameters. To edit parame-
ters again, turn OFF the [SFT] terminal input. Use parameter B031 to select whether the output
frequency is excluded from the lock state or is locked as well. Note the following:
• When the [SFT] terminal is turned ON, only the output frequency can be changed.
• Software lock can include the output frequency by setting B031.
B031
• Software lock by the operator is also possible without the [SFT] terminal being used (B031).
Mg2/Mg3 delay time 0.5 to 1 sec.
B003 (Retry wait time
before motor restart)
Frequency matching
Normal operation
4–23
SJ700 Inverter
2