Lenze MCH Series - Manual (Page 72)

68 13435744_EDBMH01_v13
70 PID MODE
This parameter activates the PID function, and selects whether the PID control will be
direct or reverse acting. Refer to Section 19.0 - MCH PID SETPOINT CONTROL. The
following options are available:
OFF
Disables the PID function to allow “standard” drive operation.
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 - FEEDBACK @ MIN and FEEDBACK @ MAX as
described in Section 19.1 - FEEDBACK DEVICES.
When PID is enabled, and the drive is in 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 PID setpoint reference is controlled by the source
defined by AUTO SOURCE (Parameter 24). The SPEED REFERENCE SOURCE
indication in the CONTROL display will indicate AKB (keypad), VDC (0-10 VDC) or IDC
(4-20 mA) depending on the setpoint reference source.
When PID is enabled, and the drive is in HAND mode, the drive will operate in an OPEN
LOOP fashion, responding directly to speed commands from the keypad or Preset #3,
depending on the setting of HAND SOURCE (Parameter 29). In this configuration, the
other settings in HAND SOURCE are disabled, and speed control will default to the
keypad.
When PID is disabled, the drive will operate in an OPEN LOOP fashion, responding
directly to speed commands from the selected speed reference source (HAND
SOURCE or AUTO SOURCE).
74
PID FEEDBACK
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 MCH 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.
75 FEEDBACK @ MIN
This parameter should be set to the value of the process variable that
corresponds to the minimum transducer feedback signal (0 VDC or 4 mA).