48 
 
 
B.) Warning and Self-Diagnosis Functions 
Protection function  Explanation 
LCD display 
(English) 
 
Low-voltage protection 
main  circuit  voltage
insufficient 
Monitor display appears if low voltage protection conditions such as a drop in 
main circuit voltage or momentary power loss occur while the inverter output is 
off. 
(blinking) 
Alarm (UV)*
1
 
DC Volt. Low 
High voltage protection 
Monitor display appears when the main circuit DC voltage rises above the 
detection level while the inverter output is off. 
(blinking) 
Alarm (OV)*
1
 
Over Voltage 
Cooling fin overheat warning 
Monitor display appears when a separate thermal protector contact is input to the 
external terminal. (Sn-15 ~ 18 = OB) 
(blinking) 
Alarm (OH2)*
1
 
Over Heat 
Overtorque detection 
This function is used to protect the machine and to monitor the inverter output 
torque. The inverter output reacts in a preset manner when the inverter output 
current exceeds the over torque detection level. The monitor display blinks when 
“operation continue” is preset. 
(blinking) 
Alarm (OL3)*
1
 
Over Torque 
 
 
 
Stall prevention 
Accel/decel is 
accomplished 
with maximum 
capacity of the 
inverter without 
tripping on over-
current or 
overvoltage a 
During 
acceleration
Inverter acceleration is stopped when 150% of or more of the inverter rated 
current is required by the load. This prevents overload protection (OL2) or 
overcurrent (OC) from occurring. When current is reduced to less than 170%, 
acceleration is enabled. 
- 
During 
normal 
operation 
Output frequency is decreased when 130% of the inverter rated current or greater 
is required by the load. This prevents motor and inverter overload (OL1, OL2). 
When current is reduced below 130%, inverter acceleration is than enabled. 
- 
During 
deceleration
Deceleration is stopped when the DC voltage is caused to rise by motor 
regenerative energy. This prevents overvoltage trips (OV). When DC voltage 
decreases, deceleration to the set value then resumes 
- 
Simultaneous normal and reverse 
rotation commands 
When forward and reverse rotation commands are simultaneously detected for a 
period of time exceeding 500 ms, the inverter is stopped according to the preset 
stop method. 
(blinking) 
Alarm (EF)*
1
 
Input Error 
External Fault 
Signal Input 
(Minor fault) 
Terminal ○
3
It is indicated on the monitor when the mode after external signal input is set to 
"Operation continue." 
 Ref. to the external faults ○
5
 ~ ○
8
 setting on page 87 
 Minor fault setting - terminal ○
3
 (Sn-12=11XX) 
terminal ○
5
 (Sn-15=2C) 
terminal ○
6
 (Sn-16=3C) 
terminal ○
7
 (Sn-17=4C) 
terminal ○
8
 (Sn-18=5C) 
(blinking) 
Alarm (EF3)*
1
 
External Fault 3 
Terminal ○
5
(blinking) 
Alarm (EF5)*
1
 
External Fault 5 
Terminal ○
6
(blinking) 
Alarm (EF6)*
1
 
External Fault 6 
Terminal ○
7
(blinking) 
Alarm (EF7)*
1
 
External Fault 7 
Terminal ○
8
(blinking) 
Alarm (EF8)*
1
 
External Fault 8 
Digital Operator communication 
error 
Operator transmission fault 1 
(Initial fault) 
Alarm (CPF00)*
1
OP Comm. Fault 
Operator transmission fault 2 
(on lime fault) 
Alarm (CPF01)*
1
OP Comm. Fault 2