Calibration and Start-Up 4-13
DC590+ DRV Series DC Digital Drive
tunes the drive's armature voltage calibration and has a range of 1.1000 to 0.9800, corresponding to -10% to +2% trim. Changes outside this range
require re-calibration as described earlier in this Chapter.
IR COMPENSATION SETUP
Properly setting the PARAMETERS::CALIBRATION::IR COMPENSATION parameter, or motor loss compensation, improves the speed
accuracy when running in armature voltage feedback.
• Run the motor without a load. Monitor the actual speed with a hand tachometer.
• With the same speed setpoint, run the motor at full load and monitor the actual speed again with a hand tachometer.
• Adjust IR COMPENSATION until the full load speed is the same as the no load speed.
NOTE Too much IR COMPENSATION causes instability.
4. MICROTACH or WIRE-ENDED ELECTRICAL ENCODERS
• You can monitor the encoder speed under DIAGNOSTICS::ENCODER in the keypad.
• Either encoder gives rotational speed for which adjustment is unnecessary; however, the process may require an accurately set speed
calibration. If required, adjust the calibration parameter CONFIGURE DRIVE::ENCODER RPM to match the motor rotational speed to the
roll speed with a hand tachometer. Speed match the motor through the ratio calculation:
New ENCODER RPM Setting = Present ENCODER RPM Setting × Desired RPM ÷ Measured RPM
5. AC/DC ANALOG TACHOMETER GENERATOR
• Settings on the analog tachometer generator feedback option card give a coarse scaling of the analog tachometer generator feedback voltage.
Fine-tune the feedback by adjusting drive software parameters.
NOTE The option card settings for AC tachometer generators are 1.3 × Calculated Value.
Use a hand tachometer to measure the motor speed and adjust SETUP PARAMETERS::CALIBRATION::ANALOG TACH CAL to scale the
overall feedback. Speed match the motor through the ratio calculation:
New ANALOG TACH CAL Setting = Present ANALOG TACH CAL Setting × Desired RPM ÷ Measured RPM
The gain range varies from 1.1000 to 0.9800, or -10% to +2% trim. Changes outside this range require a re-calibration of the feedback calibration
card as described earlier in this chapter.
If a tachometer’s observed operation is within its rated accuracy, adjustment is not recommended and will complicate speed calibration.
6. SAVE PARAMETERS when finished.
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