High Country Tek DVC80 - Manual (Page 42)

P/N: 021-00154, Rev. A.6 - updated for V4.7 Tools Page | 42
Single Coil High Side
Single Coil Low Side
High-Side Only
Process P
Setting the P in the Process PI Loop
Range: 0 to 655.00
Process I
Setting the I in the Process PI Loop
Range: 0 to 655.00
Process I Time
The time in between updates to the Integral portion of the output correction for the Process PI Loop
Range: 0.10 to 10.000
Process Selection
Range: Current Regulation, Enable Process PI, Enable Current Ramps and PWM Duty Cycle Control.
Each selection will activate the appropriate selection boxes.
Current Regulation
Current Regulation provides for automatic hardware and BIOS based adjustments to maintain the coil current at
the application code’s PWM% setting.
The Low-Side variable name sets the desired coil current. Example: Min 0 amp, Max 1 amp. Low-Side Name =
50% will cause the DVC hardware and BIOS to regulate the current to 500 ma or 50% of the current range.
This regulation will compensate for coil resistance variations typically caused by manufacturing tolerances,
increases in operating temperature and any other wiring resistances to and from the terminals of the coil.
Enable Process PI
Enable Process PI provides a facility where the application program sets a desired setpoint value and then
continually determines a feedback variable. The hardware and BIOS then adjusts the coil current to close the
error between the feedback and the setpoint. The feedback value is usually derived from a sensor that reflects
pressure or RPM and the setpoint represents the target value.
The current to the Low-Side output is increased or decreased under BIOS control to make the Feedback and
the Setpoint equal. In addition, the High Side activation is automatically switched for a Dual Coil configuration.
High Side 1 will be activated when the setpoint is greater than the feedback and High Side 2 activated when the
setpoint is less than the feedback. The Low-Side access variables are Low-Side Name.SetPoint and Low-Side
Name.FeedBack. Both SetPoint and FeedBack are variables from 0 to 100% or integer values from 0 to 1023.
This capability is generally used when the feedback signal to be regulated to is not the coil current but rather a
RPM or PSI reading from a sensor. The application program will convert the feedback sensors value to the
Low-Side Name.Feedback value. The current through the coil will increase to its maximum as long as the
feedback is less than the setpoint and decrease to zero if the feedback is greater than the setpoint. In a normal
case you should update the feedback value in your the Always code and when the feedback equals the setpoint
the coil current will remain fixed. Note that when you use the simulator and do not drive an actual coil the PWM
command will never exceed the setpoint %.
For example: if you system is capable of generating 0 to 3000 psi and you wish to generate 1500 psi you would
set the setpoint value to 50% or 512. Then typically in the Always code (since it updates every 10ms) you would
read the pressure sensors voltage to determine the current pressure and set the feedback value as a percent of
the 0-3000 psi range.
Enable Current Ramps
The output current will be ramped up or down based on the ramp times to the Low-Side Name setpoint. As the
current setpoint is ramped to in steps, the DVC hardware and BIOS change the current to the set point using the