Omron MX2 User Manual

123
"B" Group: Fine Tuning Functions Section 3-6
In most applications a controlled deceleration is desirable, corresponding to
B091=00. However, applications such as HVAC fan control will often use a
free-run stop (B091=01). This practice decreases dynamic stress on system
components, prolonging system life. In this case, you will typically set B088=01
in order to resume from the current speed after a free-run stop (see diagram
down below: active frequency matching resume). Note that using the default
setting, B088=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 3-6-1 Automatic Restart Mode on page 100), or an intelligent
input 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 fur-
ther configures all instances of
a free-run stop. Parameter
B003, Retry Wait Time Before
Motor Restart, sets the mini-
mum time the inverter will free-
run. For example, if B003=4
seconds (and B091=01) 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.
The figure at below right
describes how active fre-
quency matching resume
operates. After waiting the
time set in B003, the inverter
tries to catch the speed of the
motor shaft and output speed
depends of the setting in
B030. At this time, if the motor
current rises up to the value
set in B028, the inverter
decreases the frequency
according to the deceleration
time set in B029, and finally
comes to the required speed.
Following are the related
parameters for this control.
Code Parameter contents
B028 Current level of active frequency matching
B029 Deceleration rate of active frequency matching
B030 Start freq. selection for active freq. matching
B088 Restart mode after FRS
B091 Stop mode selection
Motor
speed
Stop mode = free-run stop
B091 = 01
0
t
[FRS]
0
t
Resume from 0Hz
B088 = 00
Zero-frequency start
Zero frequency resume
Motor
speed
Stop mode = free-run stop
B091 = 01
0
t
[FRS]
0
t
Resume from current speed
B088 = 01
Wait time
B003
0
t
Motor
current
RMS
B030
B028
B029
Active frequency matching resume

Omron MX2 Specifications

General

Model	MX2
Category	Inverter
Enclosure Rating	IP20
Control Method	V/f control, Sensorless vector control
Frequency Range	0.1 to 400 Hz
Protection	Overcurrent, Overvoltage, Undervoltage, Overheat, Short circuit
Communication	Modbus RTU
Ambient Temperature	-10 to 50 °C (without freezing or condensation)
Overload Capacity	150% for 60 seconds
Cooling Method	Fan Cooled
Humidity	5 to 95% RH (without condensation)
Altitude	Up to 1000m without derating
Voltage	200-240 VAC, 380-480 VAC
Braking Unit	Built-in (for certain models), Optional External