High Country Tek DRF Series - Manual (Page 11)

021-DRF Rev A DRF User Manual 11
Copyright © High Country Tek, Inc. – 2013
DRF
Closed-loop Valve Controller
DRFx-xxx - The title parameter is fixed. It displays the model number and the firmware version.
Cx MODE - Four modes of operation.
Open Loop Modes -
Modes 1 and 2 are open loop modes for channel 1 & 3.
For modes 1 & 2, channels 2 & 4 use its own inputs.
For modes 3 & 4, channels 2 & 4 use the inputs from channel 1 & 3 for dual-coil applications.
E.g., to drive a two-coil directional proportional valve, set C1 mode 1 and C2 mode 3. Do not overlap the input
ranges.
Closed Loop Modes - Modes 3 and 4 use the velocity PID algorithm. Channel 1 or 3 input is the command input;
channel 2 or 4 input is the feedback. Only channel 1 or 3 has output current.
When the feedback is bigger than the command, the output reduces to 0A; when the feedback is smaller than
the command, the output current increases to maximum current until the feedback matches the command.
PROPORTIONAL GAIN – Sets the P term in a PID control loop. It is a multiplication of the error added to the
output. The higher the setting, the faster the response will be. Also, higher settings result in shorter ramp time,
but it can cause oscillation. It is variable type.
INTEGRAL GAIN – Sets the I term in a PID control loop. It is the sum of the error over time. It overcomes an offset
in the output or to correct for small deviations over time. A higher gain will result in more integral control but
can cause oscillation. It is variable type.
DERIVATIVE GAIN – Sets the D term in a PID control loop. It is the rate of change of error. The higher the
derivative gain, the quicker the system will respond to sudden changes. It is variable type.
Mode Enable Channels comments
1 CUR NO ENBL 1,3 Open loop, use its own input
2 CUR USE ENBL X 1,3 Open loop, use its own input
3 VEL NO ENBL 1,3 Closed-loop, C1 & C3 are the command inputs
4 VEL USE ENBL X 1,3 Closed-loop, C1 and C3 are the command inputs
1 IN2 NO ENBL 2,4 Open loop, single-coil valve, use its own input;
Closed-loop, feedback
2 IN2 USE ENBL X 2,4 Open loop, single-coil valve, use its own input;
Closed-loop, feedback
3 IN1 NO ENBL 2,4 Open loop, dual-coil valve, use inputs from C1 & C3
4 IN1 USE ENBL X 2,4 Open loop, dual-coil valve, use inputs from C1 & C3