Omron 3G3RX - Current Limitation Functions

RX Quick Start Guide 33
PROGRAMMING RX
In standard operation, inverter uses a reference source selected by A001 for the output frequency which may be a fixed or vari-
able value. To enable PID operation is necessary to set A071 to “01” and this will cause the inverter to calculate the target fre-
quency or set point. This presents some advantages like potential energy saving and direct control over the process variable
instead of the motor speed.
3.21 Current limitation functions
Overload Restriction reduce the output frequency while motoring or increase
it during regeneration to restrict the overload when the output current exceeds
a certain limit. You can adjust the inverter to apply overload restriction only
during constant speed allowing higher currents for acceleration.
Additionally two separate sets of parameters are available and is possible to
choose between them by intelligent input terminal “39: OLR”
Over-current Trip Suppression function monitors the motor current
and actively changes the output frequency profile to keep the motor cur-
rent below 150% of the motor rated current. Basically the acceleration
ramp is stopped above this current and only restarts when the current
goes below the set value. It avoids the trip but the total acceleration time
could be longer when this function is enable.
Please consider that this function doesn’t operate keeping a constant
motor current so is still possible to have an over-current trip during
extreme acceleration.
Parameter Parameter name Description
A071 PID selection 00: OFF (Disabled)
01: ON (+) (Enabled)
02: ON (+/-) (Reverse output enabled)
A072 PID P gain 0.2 to 5.0
A073 PID I gain 0.0 to 3600.0 s
A074 PID D gain 0.00 to 100.00 s
A075 PID scale 0.01 to 99.99
A076 PID feedback selection 00: OI
01: O
02: Modbus (RS485 communication)
03: Pulse (Pulse train frequency)
10: Math (Operation function output)
A077 Reverse PID function 00: OFF (Deviation = Target value - Feedback value)
01: ON (Deviation = Feedback value - Target value)
A078 PID output limit function 0.0 to 100.0%
A079 PID feed forward selection 00: Disabled
01: O
02: OI
03: O2
C044 PID deviation excessive level 0.0 to 100.0%
C052 PID FB upper limit 0.0 to 100.0%
C053 PID FB lower limit 0.0 to 100.0%
Motor
current
Restriction area
B022
0
t
Output
frequency
0
t
B023
Regenerating
Powering
B023
Motor
current
0
t
Output
frequency
0
t
Stops accel
Resumes accel
B027 = 01
OC LAD STOP = Enabled
Set acc time
Actual acc time
Approx. 150% of the inverter
rated current