Hitachi hitachi series inverter 사용자 설명서

 

38 

Frequency arrival output [FA1] uses the 
standard output frequency (parameter 
F001) as the threshold for switching. In 
the figure to the right, Frequency Arrival 
[FA1] turns ON when the output 
frequency gets within Fon Hz below or 
Fon Hz above the target constant 
frequency, where Fon is 1% of the set 
maximum frequency and Foff is 2% of 
the set maximum frequency. This 
provides hysteresis that prevents output 
chatter near the threshold value. The 
hysteresis effect causes the output to 
turn ON slightly early  as the speed 
approaches the threshold. Then the 
turn-OFF point is slightly delayed. Note 
the active low nature of the signal, due to 
the open collector output. 

Frequency arrival output [FA2/FA4] 
works the same way; it just uses two 
separate thresholds as shown in the 
figure to the right. These provide for 
separate acceleration and deceleration 
thresholds to provide more flexibility than 
for [FA1]. [FA2/FA4] uses 

C042

/

C045

 

during acceleration for the ON threshold, 
and 

C043

/

C046

 during deceleration for the 

OFF threshold. This signal also is active 
low. Having different accel and decel 
thresholds provides an asymmetrical 
output function. However, you can use 
equal ON and OFF thresholds, if desired. 

Frequency arrival output [FA3/FA5] works 
also the same way, only difference is 
arriving at set frequency. 
 

 

 

 

FA1 

signal

Output 

freq.

F001 

F001 

Foff 

Fon 

ON

Foff 

ON 

0

FA2/FA4 

signal

Output

freq.

thresholds

C042

/

C045

ON 

0

C043

/

C046

Fon 

Foff 

FA3/FA5 

signal

Output

freq.

thresholds

C042

/

C045

0

C043

/

C046

Foff 

Foff 

Fon 

ON

ON