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TECHNICAL DOCUMENT

ELECTRONIC 38

PVW/H/C VV (A Frame)

STROKE CONTROL WIRING

General Notes: This document references schematic wiring standards and software configurations/calibrations required to operate a specific pump, utilizing the Oilgear EPC amplifier. The pump is identified by a partial model code. Complete model codes are defined in pump bulletins. “L” (list) numbers or serial numbers may also identify pumps. Contact the Oilgear Company to cross reference “L” and serial numbers to model codes. Reference Technical Document 836261 for the “Flow Control Program” and Technical Document 836260 for the EPC “User Manual”. Both may be accessed from the Internet at www.oilgear.com. Caution! Improper wiring, configurations & calibrations may result in loss of pump control, improper operation, damage to components, machinery and even personal injury. (*) Calibration data for LVDT feedback, pump response gain, and LVDT offset, as listed in the table, are initial values. The initial values (*) are adequate for many applications but may need to be optimized for specific applications. • Pump Rotation - Pumps are designed for clockwise (CW) or counter-clockwise (CCW) rotation. • • Port of Delivery LVDT Location - Pump & control design, mounting clearance and/or mounting preference, determine LVDT location. Location is defined as left hand side facing shaft (LHSFS), right hand side facing shaft (RHSFS) or top. The LVDT may be inside a control housing or as a component (visible). See “LVDT Invert” for control considerations. - Pumps may be one way, neutral to “A” or “B” port or two way (bi-directional) “A” to neutral to “B”, depending on pump design or application. The table assumes “A” port delivery. • Polarity (Command) - Commands may be either current (see Technical Document 836261) or voltage, plus (+) or minus (-) DC voltage polarity, for port of delivery as determined above. The table assumes a plus (+) voltage for “A” port delivery for standardization. • Polarity (LVDT) - The control/LVDT physical location, and schematic diagram wiring, determine LVDT feedback voltage polarity. “LVDT Invert” is set to insure command and feedback cancel. • Polarity, Module (Current) - The control/servo valve mounting physical location, and schematic diagram wiring, determine servo valve pilot flow to pump stroking pistons, and ultimately pump “Port of Delivery”. The table assumes a “Command polarity” and “Current Polarity” for “A” port delivery, unless otherwise listed. • Dither (Output Current) - Provides approximately 200 Hz current pulse to help keep servo valve from sticking (silting up). Value is based on valve design. • Current Limit - Matches electrical maximum saturated current output, to design limit specification of servo valve. Wrong current limit entries may result in servo valve reduced performance and life. • LVDT Feedback Gain - Matches maximum electrical LVDT feedback signals, to pump full mechanical stroke (flow) range. Analog Output #2 is configured for LVDT 0 to approximately +/- 10V DC feedback as a standard for customer use. • LVDT Feedback Offset - Matches minimum electrical LVDT feedback signals, to pump minimum mechanical flow (neutral). The initial 512* assumes an ideal condition. Hydraulic circuit design, mechanical pump machining & electrical component, tolerances, may require resetting the offset. • Stroke Controller Gain - Sets pump response (reaction time) and accuracy of stroking. PVW/H/C VV (A Frame) Notes: • The servo valve (VSC4/SCVA) is always mounted on top. • LVDT is rated +/- 0.50 inch stroke. • The pump is rated at +/- 0.462 inch stroke.
Telephone: Fax: Website: (414) 327-1700 (414) 327-0532 www.oilgear.com The Oilgear Company 2300 S. 51st. Street Milwaukee, WI USA 53219 Issued: Aug, 2004

Bulletin 836269C