Specifications

NORMAL Enables the PID function for direct acting systems. An

increase in the feedback variable will cause a decrease in motor

speed.

REVERSE Enables the PID function for reverse acting systems. An

increase in the feedback variable will cause an increase in

motor speed.

NOTE: The REVERSE selection is not used to compensate for reverse acting feedback

devices. If a reverse acting feedback device is used, program Parameters 75 and 76 - FB @

MIN and FB @ MAX as described in Section 19.1 - FEEDBACK DEVICES.

When PID is enabled, and the drive is in REMOTE and AUTO mode, the drive will operate

in a CLOSED LOOP fashion, responding to the feedback signal in order to maintain the

process setpoint. In this case, the setpoint reference can be a 0-10 VDC or 4-20 mA signal,

or the keypad. The SPEED REFERENCE SOURCE indication in the CONTROL display

will indicate VDC (0-10 VDC), IDC (4-20 mA), or AKB (keypad), depending on the

setpoint reference.

When PID is enabled, and the drive is in LOCAL and AUTO mode, the drive will also

operate in a CLOSED LOOP fashion. However, in this case, the only setpoint reference

available is the keypad, and the SPEED REFERENCE SOURCE indication in the

CONTROL display will indicate AKB.

When PID is enabled, and the drive is in MANUAL and LOCAL or REMOTE mode, the

drive will operate in an OPEN LOOP fashion, responding directly to speed commands from

the keypad only. The SPEED REFERENCE SOURCE indication in the CONTROL display

will indicate MKB.

When PID is disabled, the drive will operate in an OPEN LOOP mode, responding directly

to speed commands from either the keypad (MANUAL mode) or an analog input signal

(AUTO mode).

74 PID FB (PID FEEDBACK SOURCE)

This parameter selects the terminal to be used for the feedback signal, and can be set to TB-

5A or TB-5B. TB-5A is used for 0-10 VDC signals, and TB-5B is used for 4-20 mA signals.

NOTE: The AC400 has only one analog input of each type, so the same type of signal

cannot be used for feedback and setpoint reference. For example, a 4-20 mA signal from a

transducer could not be used as a feedback signal if the setpoint is being controlled by a 4-20

mA signal from a PLC.