Altivar 312 Variable Speed Drives Page 15 Introduction

15 Altivar 312 variable speed drives Functions Functions (continued) PI regulator This function is used for simple control of a flow rate or a pressure with a sensor supplying a feedback signal adapted to the drive. It is suitable for pumping and ventilation applications. PI reference: - Internal regulator reference, adjustable from 0 to 100 - Regulation reference selected from all the possible types of regulation reference - Preset PI references 2 or 4 preset PI references adjustable from 0 to 100, require the use of 1 or 2 logic inputs respectively Manual reference - Speed reference selected from all the possible types of speed reference PI feedback: - Analog input AI1, AI2 or AI3 Auto/Man: - Logic input LI for switching operation to speed reference (Man) or PI regulation (Auto) During operation in automatic mode, the process feedback can be adapted to correct inverse PI, adjust the proportional and integral gain, or apply a ramp (time = ACC - DEC) for establishing the PI action on starting and stopping. The motor speed is limited to between LSP and HSP. Note: The PI function is incompatible with the Preset speeds and JOG functions. The PI reference can also be transmitted on line via the Modbus RS 485 serial link or via the CANopen bus. Current limit switching A second current limit can be configured between 0.25 and 1.5 times the nominal drive current. This function limits the torque and the temperature rise of the motor. Switching between the two current limits can be enabled via: A logic input A bit in a Modbus or CANopen control word Limiting low speed operating time The motor is stopped automatically after a period of operation at low speed (LSP) with a zero reference and a run command present. This time can be set between 0.1 and 999.9 seconds (0 corresponds to an unlimited time). Factory setting: 0 s. The motor restarts automatically on the ramp when the reference reappears or if the run command is interrupted and then re-established. This function is suitable for automatic stopping/starting of pressure-regulated pumps. Motor switching This function allows two motors with different powers to be supplied alternately by the same drive. Switching must take place with the drive stopped and locked, using an appropriate sequence at the drive output. The function can be used to adapt the motor parameters. The following parameters are switched automatically: Nominal motor voltage Nominal motor frequency Nominal motor current Nominal motor speed Motor cosine Phi (power factor) Selection of the type of voltage/frequency ratio for motor 2 IR compensation, motor 2 Motor frequency loop gain Motor stability Motor slip compensation Motor thermal protection is disabled by this function. Motor switching can be enabled by: A logic input A bit in a Modbus or CANopen control word With hoisting applications, this function enables a single drive to be used for vertical and horizontal movements. ACC DEC RPG RIG PIC X1 FBS + PI reference PI feedback Manual reference Reference Auto Man PI inversion PI regulator Ramp Multiplier Auto/man ACC: Acceleration DEC: Deceleration FBS: PI feedback multiplication coefficient HSP: High speed PIC: Reversal of the direction of correction of the PI regulator LSP: Low speed RIG: PI regulator integral gain RPG: PI regulator proportional gain HSP LSP PI feedback

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