HP PWM Valve Driver

HP Single & Dual Coil PWM Valve Driver

Not recommended for new designs

Available in limited quantities.

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The HP proportional single coil or dual coil valve drivers use PWM (pulse width modulation) to vary current to the valves. Current to the valve is regulated, allowing the valve coils to heat up and increase their resistance without affecting operation. Coils rated lower than the power supply voltage may be used to provide headroom against voltage drops in the wiring and the valve driver, or to allow the same coil to be used with 12 volt supplies. This driver uses a microprocessor to read user controls and regulate coil current. Ten turn potentiometers are provided to allow the user to adjust the maximum current(s), minimum current(s), ramp time(s), and where applicable, the crossover between coils, the dither amplitude, dither frequency. If preferred, all or some of these pots can be eliminated and these settings can be accomplished via the HCT Serial Communications System.

Rugged Construction:

¨ Fuse protection in series with power to the unit allows inputs and outputs to be hooked up backwards, shorted to each other, grounded or hooked up to +/- 30 volts without harming the unit.

¨ Power Supply input is protected against automotive spikes.

¨ Epoxy potting provides mechanical protection and environmental resistance, including sealing potentiometers against moisture.

¨ Operating temperature range is -40°C to +75°C.

Control Input:

¨ Accepts control voltage and current inputs of -5V to +5V, 0 to +5V, 0 to +10V, 0 to 20 mA. or 4 to 20 mA. or an external potentiometer.

Note: A 10k potentiometer with a knob is included with every valve driver.

Power Supply:

¨ Power supply voltage range is from 11-14 volts. (12 Volt Systems)

¨ Red power LED indicates sufficient power present for proper operation.

¨ The coil can be driven to within 1.0 volt of the power supply voltage at maximum current.

Note: Some 10-volt coils require up to 13 volts for full valve shift when hot, making this an important feature for mobile systems.

Optical Interface:

An optical interface “port” located on the unit allows the valve driver to communicate to a PC’s serial port using HCT’s, "Opto3000", optical interface device. This non-corrosive port uses light for communication preventing the possibility of damage to the PC.

¨ The PC can program all valve driver functions set by pot as well as select the desired input range, enable and adjust a dead band at crossover, adjust the coil current regulation parameters and select desired behavior for out of range inputs.

¨ A system calibration routine is available to guide the user through the process of setting up the valve driver to function in the system. This method is much easier than using ten turn pots, as all actions are prompted for, and the input and output values are visible on the PC’s screen.

¨ The internal parameters of the valve driver can be saved or restored from disk, allowing replacement of a valve driver with a unit preset to be exactly the same as the original.

¨ The valve driver reports the power supply voltage, control input levels, coil current and PWM% both as numbers and a running graph for ease of troubleshooting. These values can be logged to a file for future reference or trouble shooting assistance.

Programmable Speed Reduction:

¨ LOW SPEED H input allows the driver to be placed in the user defined low speed mode. The driver will regulate to the user defined PWM current when this input is enabled.

Current Output:

¨ The valve driver uses current feedback to precisely set the current through the valve.

¨ Outputs to the valves are protected against short circuits across the valve's coil.

¨ The valve driver disables the output during error conditions.

Ramp:

¨ The valve driver ramp range is from 0 to 120.seconds

Dither:

¨ An optional on-board dither generator provides dither with adjustable amplitude and factory preset adjustable frequency. Note: Amplitude can be left at zero should dither not be required.

Status LEDs:

¨ Power OK LED - indicates power supply input voltage is greater than 8.0 VDC.

¨ PWM % LED - indicates relative percent of current output from the unit.

Note: This LED will flash red / off for a shorted coil, or green / off for an open coil. The HPD will have two PWM % status LEDs

¨ An error LED will flash if an error condition has been detected.

Note: Error conditions include: Power supply voltage out of range, open or shorted coil, insufficient power supply voltage to drive the commanded coil current, or control input out of range.

Options:

¨ "Q" Option, Weatherpack Connectors with 6-inch leads. See Order Guide for details.

- "V" Option, Single-turn waterproof potentiometer with bezel marked 0 to 100. See Order Guide for details.