Omron R88D-GT series, User Manual

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5-17
5-8 Electronic Gear
5
Ope
rati
ng Func
tions
rotation.
• When an encoder with a resolution of 2,500 pulses/rotation is used, the number of internal
command pulses (F) in the Servo Drive will be 10,000 pulses/rotation (2,500 pulses/rotation
×
4).
• Given the conditions above, the relation between the number of command pulses per Servomotor
rotation (f) and the electronic gear ratio is as follows:
Calculation Examples (For a 2,500 pulses/rotation encoder)
• Make the following settings to operate with 2,000 pulses/rotation.
• Similarly, make the following settings to operate with 1,000 pulses/rotation.
• Conversely, make the following settings to increase the resolution per rotation and operate with
40,000 pulses/rotation.
The setting ranges for Pn48, Pn49, and Pn4B are from 1 to 10,000, so reduction is required in the
settings.
Calculation Example (For a 17-bit encoder)
• Use the following setting to operate at 5,000 pulses/rotation:
Set the parameters so that the command pulse frequency multiplied by the electronic gear ratio
does not exceed 80 Mpps. If 80 Mpps is exceeded, alarm 27 will occur.
Example:
The following calculation is for an absolute encoder with a resolution of 131,072, an electronic gear
setting of 500 (Pn48 = 1 , Pn49 = 1 , Pn4A = 17 , Pn4B = 500 ), and a command pulse frequency
of 500 kpps.
500 kpps
× 131,072/500 = 131,072,000 = 131.072 Mpps, which exceeds 80 Mpps.
The calculation changes as follows if the electronic gear is set to 5,000 (Pn48 = 1 , Pn49 = 1 , Pn4A
= 17 , Pn4B = 5,000) and the command pulse frequency is 500 kpps.
500 kpps
× 131,072/5,000 = 13,107,200 =13.1072 Mpps, which does not exceed 80 Mpps.
F = f
×
Pn4B
Pn48
×
2 Pn4A
=
Pn4B
Pn48
×
2
Pn4A
F
f
10000
f
=
10000 (Pn48)
×
2
0 (Pn4A)
2000 (Pn4B)
10000 (Pn48)
×
2
0 (Pn4A)
1000 (Pn4B)
10000
=
40000
2500 (Pn48)
×
2
0 (Pn4A)
10000 (Pn4B)
1 (Pn48) ×2
17 (Pn4A)
5000 (Pn4B)