Group 25: Critical Speeds
This group denes up to three critical speeds or ranges of speeds that are to be avoided due, for example, to mechanical
resonance problems at certain speeds.
Table 35: Group 25: Critical Speeds
Code Description Range Resolution Default S
2501 CRIT SPEED SEL 0, 1 1 0
Sets the critical speeds function on or off. The critical speed function avoids specic speed ranges..
0 = OFF – Disables the critical speeds function.
1 = ON – Enables the critical speeds function.
Example: To avoid speeds at which a fan system vibrates badly:
• Determine problem speed ranges.
Assume they are found to be: 18…23 Hz and 46…52 Hz.
• Set 2501 CRIT SPEED SEL = 1.
• Set 2502 CRIT SPEED 1 LO = 18 Hz.
• Set 2503 CRIT SPEED 1 HI = 23 Hz.
• Set 2504 CRIT SPEED 2 LO = 46 Hz.
• Set 2505 CRIT SPEED 2 HI = 52 Hz.
2502 CRIT SPEED 1 LO 0.0…500.0 Hz 0.1 Hz 0.0 Hz
Sets the minimum limit for critical speed range 1.
• The value must be less than or equal to 2503 CRIT SPEED 1 HI.
• Units are rpm, unless 9904 MOTOR CTRL MODE = 3 (SCALAR SPEED), then units are Hz.
2503 CRIT SPEED 1 HI 0.0…500.0 Hz 0.1 Hz 0.0 Hz
Sets the maximum limit for critical speed range 1.
• The value must be greater than or equal to 2502 CRIT SPEED 1 LO.
• Units are rpm, unless 9904 MOTOR CTRL MODE = 3 (SCALAR SPEED), then units are Hz.
2504 CRIT SPEED 2 LO 0.0…500.0 Hz 0.1 Hz 0.0 Hz
Sets the minimum limit for critical speed range 2.
• See parameter 2502, page 51.
2505 CRIT SPEED 2 HI 0.0…500.0 Hz 0.1 Hz 0.0 Hz
Sets the maximum limit for critical speed range 2.
• See parameter 2503, page 51.
2506 CRIT SPEED 3 LO 0.0…500.0 Hz 0.1 Hz 0.0 Hz
Sets the minimum limit for critical speed range 3.
• See parameter 2502, page 51.
2507 CRIT SPEED 3 HI 0.0…500.0 Hz 0.1 Hz 0.0 Hz
Sets the maximum limit for critical speed range 3.
• See parameter 2503, page 51.
aCTual sIgnals and parameTers
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