Section 1
General Information
Programming & Operation 4-21MN715
Table 4-2 Parameter Block Definitions Level 2 Continued
Block Title Parameter Description
BRAKE ADJUST
Continued Stop Brake Time The maximum number of seconds that DC injection brake voltage will be applied to the
motor windings after a stop command. After the time specified by this value, DC
injection braking is automatically turned off. If DC injection braking starts at a
frequency less than the DC brake frequency parameter, the stop brake time is
calculated as follows:
BrakeTime +StopBrake Time X OutputFrequency at Braking
DC Brake Frequency
Brake on Start If set to ON, turns DC injection braking ON for a period of time (Start Brake Time) when
a run command is issued. This ensures the motor is not rotating. Braking will
automatically turn off and the motor will accelerate at the end of the start brake time.
Start Brake Time The amount of time that DC injection braking will be applied after a run command is
issued. This will only occur if brake on start is set to ON. Braking may cause the
motor to overheat for applications that require frequent starts/stops. Be careful in
selecting this value. The start brake time should be just long enough to ensure the
motor shaft is not rotating when a start command is issued.
PROCESS
CONTROL Process Feedback
Invert Feedback
Setpoint Source
Setpoint Command
Set PT ADJ Limit
At Setpoint Band
The type of signal used for the process feedback in the PID setpoint control loop.
OFF – The process feedback signal is not inverted (no polarity change).
ON – Causes the process feedback signal to be inverted. Used with reverse acting
processes that use a unipolar signal such as 4-20mA. If “ON”, the PID loop will see a
low value of the process feedback signal as a high feedback signal and a high value
of the process feedback signal as a low feedback signal.
The source input reference signal type to which the process feedback will be compared.
If “Setpoint CMD” is selected, a fixed value that is entered in the setpoint command
parameter (of the Level 2 Process Control block) will be used.
The setpoint value for the PID loop that the control will try to maintain. This is only used
when the setpoint source parameter is set to “Setpoint Command”. Negative
percentage values are ignored in the PID loop if the feedback signal contains only
positive values (such as 0-10VDC).
The maximum frequency correction value to be applied to the motor (in response to the
maximum feedback setpoint error). For example, if the max output frequency is 60
Hz, the setpoint feedback error is 100% and the setpoint adjustment limit is 20%, the
maximum speed the motor will run in response to the setpoint feedback error is ±12
Hz. (60Hz x 20%= 12Hz or a total of 24 Hz total output band-width centered around
the effective setpoint frequency).
The operating band within which the at setpoint opto output is active (turned ON). This
feature indicates when the process is within the desired setpoint range. For example,
if the setpoint source is 0-10VDC and the at setpoint band value is 10%, the at
setpoint opto output will turn on if the process is within (10 x 10% = 1) ±1VDC of the
setpoint.
Process PROP Gain
Process INT Gain
Process DIFF Gain
Follow I:O Ratio
The PID loop proportional gain.
The PID loop Integral gain.
The PID loop differential gain.
The ratio of the master input to the follower output. Requires the master pulse
reference/ isolated pulse follower expansion board. For example, the left number is
the master input rate. The number to the right of the colon is the follower output rate.
If you wish the follower to run twice the speed of the master, a 2:1 ratio is entered.
Fractional ratios such as 0.5:1 are entered as 1:2.
Process Type Selects whether process control is Forward Acting or Reverse Acting.