6U Modular Multi-Axis Linear Amplifier Systems

The VRS-LA6U Varedan Rack Systems build upon the proven performance and reliability of Varedan Technologies linear amplifiers and VPS power supplies by enabling the creation of compact and modular multi-axis packages in the industry standard rack mountable 6U form factor. The LA6U Linear Servo Amplifier Series are the perfect choice for systems requiring low radiated noise and zero distortion. These high power linear amplifiers are well suited to drive loads such as brushless and brush servo motors or voice coils. Our designs incorporate class AB linear output stages for true linear output.

The design of these amplifiers includes an onboard high-speed DSP that monitors all key system functions in real time, and provides protection for the outputs by limiting output power to a “Safe Operating Area”. An intelligent user interface allows setup and storage of all system parameters via the serial interface. Non-volatile memory provides storage of the parameters during power off conditions.

A complete multi-axis system of up to five LA6U linear amplifier modules and one VPS-LA6U power supply module can be installed in a standard 19 inch rack reducing system wiring and system complexity. The pluggable LA6U linear amplifier modules are available in multiple power levels and motor configurations including three-phase brushless, single-phase brush/voice coil, and the new “Independent” configuration capable of driving three separate single phase loads from each LA6U amplifier module. This allows the engineer to create and configure up to an astonishing 15 axis high power precision linear motion control solution with one 6U size 19 inch rack mountable enclosure.

Modes of Operation

Current Mode

In current mode the amplifier is commutated by an external controller. Our Linear Amplifier Series are designed to drive single & 3-phase loads by analog input commands.

These current mode linear amplifiers are available in the following standard configurations:

“T-Mode” – Three-phase current output. This configuration is used for driving three phase rotary or linear motors with a full-bridge output configuration. In this configuration the amplifier receives two sinusoidal current commands for phases A and B (ABSine). The phase C command is generated internally in the amplifier.

“S-Mode” – Single-phase H-Bridge type output. This configuration is used for driving single phase loads such as brush-type motors or voice coils. In this mode the amplifier can deliver the full rail-to-rail bipolar bus voltage to the load.

The following is an example of S-Mode operation. When operating in full-bridge configuration (Phase to Phase), the maximum bus voltage that can be applied to the voice coil is the full B+ to B- voltage. For example if you are using a +/-50VDC bus and a full-bridge connected voice coil, the maximum voltage that can be applied to the voice coil is +100V or -100V. This is illustrated in the following picture which shows positive current from PhaseB to PhaseC (+100V):

Linear Amplifier Sizing — S-Mode Operation

“D-Mode” – Dual independent Half-Bridge type outputs. This mode is used to drive two independent single phase loads, such as brush-type motors or voice coils, with one amplifier module. In this mode the amplifier can deliver half of the full rail-to-rail bipolar bus voltage to the load. The sum total wattage requirements of the two independent loads must be within the capabilities of the amplifier module.

The following is an example of D-Mode operation, (or one or two voice coil connected to a T-Mode amplifier). When operating in Half-Bridge configuration (Phase to Common), the maximum bus voltage that can be applied to the voice coil is 1/2 of the full +/-Bus supply. For example if you are using a +/-50VDC bus and a half-bridge connected voice coil, the maximum voltage that can be applied to the voice coil is +50V or -50V. This is illustrated in the following picture which shows positive current from phaseB to Common (+50V).

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Standard Models

Amplifier Series	Current Continuous/Peak	Power Continuous/Peak	±VDC Bus Voltage	Dimensions	Weight
LA6U-415	5/15 Amps	400/1200 Watts	±12 - ±150VDC	11.025" x 9.19 x 2.77"	4.6 lbs.
LA6U-525	10/25 Amps	500/1500 Watts	±12 - ±150VDC	11.025" x 9.19 x 2.77"	5.0 lbs.
LA6U-540	20/40 Amps	500/3000 Watts	±12 - ±150VDC	11.025" x 9.19 x 2.77"	5.5 lbs.

Key Design Benefits

Linear Output Control for quiet operation
True Rail to Rail Output
Multiple Power Levels Share Common Interface
Three-Phase, Single-Phase & Independent mode versions
Safe Operating Area Protection of Power Devices
Zero Crossover Distortion
Over Current Protection

Over Voltage Protection
Up to 10kHz Bandwidth
Configure using RS232 serial cable
7-Segment Display Shows Status in Real-Time
Factory Programmable Options
Custom tuning for highest performance available

6U rack-mount amplifier/ power supply enclosure system
Multiple power levels share common interface
Standard backplanes simplify system wiring / custom backplane designs available
Up to 5 amplifier module enclosure fits into standard 19 inch equipment racks
Up to 2 amplifier module Stand-Alone enclosure available

Models & Specifications

LA6U Specifications

Component		Datasheet	Installation Drawing	Manual	STEP File
	LA6U Series Linear Amplifier Modules - The LA6U series linear servo amplifier modules are the next generation of high-performance motion products from Varedan Technologies. They are the perfect choice for systems requiring low radiated noise with zero distortion. These current mode linear amplifiers are well suited to drive loads such as brushless and brush servo motors or voice coils.
	VPS-LA6U Power Supply Module - The VPS-LA6U power supply module is designed to slide into our 6U rack mount system. The VPS-LA6U accepts a center tapped single or three phase AC input from an external transformer to generate the +/- DC bus voltage. In addition, the VPS-LA6U also generates +5VDC@10A, +/-15VDC@3A & +24V@2A.
	VRS-LA6U-5A 5 Amplifier Module Rackmount Enclosure - The VRS-LA6U-5A is a modular enclosure that holds up to 5 LA6U-400 or LA6U-500 series linear amplifier modules along with one VPS-LA6U power supply module giving you up to 15 axis of control in a standard 19″ rackmount configuration.
	VRS-LA6U-2A 2 Amplifier Module Stand Alone Enclosure - The VRS-LA6U-2A is a modular enclosure that holds up to 2 LA6U-400 or LA6U-500 series linear amplifier modules along with one VPS-LA6U power supply module giving you up to 6 axis of control in a stand-alone enclosure.