Hitachi L100 Manuale Utente

Pagina di 192
“B” Group: Fine Tuning Functions
Configur
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B_88: Restart Mode Configuration – You can configure how the inverter resumes 
motor output control after a free-run stop. Setting B_88 determines whether the inverter 
will ensure the motor always resumes at 0 Hz, or whether the motor resumes from its 
current coasting speed (also called frequency matching). The Run command may turn 
OFF briefly, allowing the motor to coast to a slower speed from which normal operation 
can resume.
In most applications a controlled deceleration is desirable. However, applications such 
as HVAC fan control will often use a free-run stop. This practice decreases dynamic 
stress on system components, prolonging system life. In this case, you will typically set 
B_88=01 in order to resume from the current speed after a free-run stop (see diagram 
below, right). Note that using the default setting, B_88=00, can cause trip events when 
the inverter attempts to force the load quickly to zero speed.
NOTE: Other events can cause (or be configured to cause) a free-run stop, such as 
power loss (see 
terminal [FRS] signal. If all free-run stop behavior is important to your application (such 
as HVAC), be sure to configure each event accordingly.
An additional parameter further configures all instances of a free-run stop. Parameter 
B_03, Retry Wait Time Before Motor Restart, sets the minimum time the inverter will 
free-run. For example, if B_03 = 4 seconds and the cause of the free-run-stop lasts 
10 seconds, the inverter will free-run (coast) for a total of 14 seconds before driving the 
motor again.
B_86 Frequency scaling 
conversion factor
Specify a constant to scale the 
displayed frequency for D_07 
monitor, range is 0.1 to 99.9
1.0
1.0
1.0
/Hz01.0     0.00
B_87 STOP key enable
Select whether the STOP key 
on the keypad is enabled, two 
option codes:
00 ...enabled
01 ...disabled
00
00
00
STOP-SW       ON
“B” Function
Run 
Mode 
Edit
Defaults
Func.
Code
Name /
SRW Display
Description
–FE 
(CE)
–FU 
(UL)
–FR 
(Jpn)
Units
B_88 = 00
B_88 = 01
[FW, RV]
Motor 
speed
t
Resume from 0Hz
Zero-frequency start
t
Resume from current speed
[FW, RV]
Motor 
speed
B 03
Wait time
[FRS]
[FRS]