KOLLMORGEN SERVOSTAR 403M-P S403M-PB AC Servo Drive – SERVOSTAR 400

KOLLMORGEN SERVOSTAR 403M-P S403M-PB — Single-Axis AC Servo Amplifier in the SERVOSTAR 400 Platform

The SERVOSTAR 403M-P, identified by its factory model code S403M-PB, is a fully digital, single-axis AC servo amplifier belonging to KOLLMORGEN’s SERVOSTAR 400 drive family. Within a closed-loop motion control architecture, this unit occupies the power conversion and regulation layer: it receives a motion command from an upstream controller — either as a ±10 VDC analog reference or as cyclic process data over PROFIBUS-DP — and translates that command into precisely modulated three-phase output current to drive an AC brushless servo motor. The drive executes a cascaded control structure: an outer position loop feeds a velocity loop, which in turn commands the innermost current (torque) loop. All three loops are resolved in a fixed-point DSP core operating at a 62.5 µs servo cycle, giving the current loop a bandwidth sufficient to track torque transients without introducing phase lag that would destabilize the velocity loop.

At 3 A continuous and 9 A peak output, the S403M-PB is sized for servo axes in the sub-kilowatt range — typical applications include rotary indexing tables, precision lead-screw axes, label applicator heads, and single-axis pick-and-place mechanisms. The 60 mm panel width allows high-density cabinet layouts when multiple axes are required. DC bus architecture supports shared bus configurations across multiple SERVOSTAR 400 units in the same enclosure, enabling regenerative energy from decelerating axes to be absorbed by accelerating axes, reducing net energy draw and thermal load on the braking resistor circuit.

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Technical Parameters

Hardware Logical Analysis

The S403M-PB power stage is built around a three-phase IGBT bridge with gate drive circuits that implement dead-time compensation in hardware. Dead-time compensation is critical at 8–16 kHz switching: without it, the blanking interval between complementary gate signals introduces a systematic voltage error proportional to load current direction, which manifests as torque ripple at low speeds. The SERVOSTAR 400 hardware corrects this by measuring DC bus voltage and output current polarity on each PWM cycle and injecting a compensating duty-cycle offset, keeping torque linearity intact down to near-zero speed — a requirement for applications such as vertical load holding or slow-speed contouring.

The current measurement path uses two shunt resistors in the lower legs of the IGBT bridge, with differential amplifiers feeding a 12-bit ADC sampled synchronously with the PWM carrier. Synchronous sampling eliminates switching noise aliasing that would otherwise corrupt the current feedback signal and force the current loop bandwidth to be derated. The result is a current loop crossover frequency in the range of 1–2 kHz, which provides adequate phase margin for the velocity loop to be tuned to several hundred Hz bandwidth on low-inertia loads.

EMC design on the SERVOSTAR 400 platform follows a layered approach. The DC bus capacitor bank is physically located close to the IGBT module to minimize the high-frequency current loop area, reducing radiated emissions from the switching node. The encoder interface uses RS-422 differential signaling with 120 Ω line termination, making it immune to common-mode noise induced by long cable runs in electrically noisy machine environments. The PROFIBUS-DP physical layer (RS-485) similarly uses differential signaling with galvanic isolation at the drive boundary, preventing ground loop currents from corrupting fieldbus communication when the drive shares a cabinet with variable-frequency drives or other high-power switching equipment.

The inertia identification routine, accessible via DRIVE.EXE, applies a series of controlled velocity perturbations and measures the resulting torque response to estimate the total reflected inertia at the motor shaft. This value is used to pre-scale the velocity loop proportional gain, placing the initial operating point within a stable region before fine-tuning. For machine builders commissioning multiple identical axes, this automated procedure reduces per-axis setup time and eliminates the variability introduced by manual gain estimation.

System Integration Benefits

• PROFIBUS-DP Slave Node: The PB suffix enables the S403M-PB to operate as a DP slave with configurable node address (1–125 via DIP switch), integrating directly into Siemens S7, Beckhoff, or any IEC 61158-compliant master without gateway hardware. Cyclic data exchange supports velocity setpoint, torque limit, and status word at the DP cycle rate.
• Cascaded Loop Transparency: All three control loop gains (position Kp, velocity Kp/Ki, current Kp/Ki) are individually accessible via serial interface, allowing control engineers to characterize and document the exact tuning state of each axis — essential for machine replication and spare-drive swap-in procedures.
• Deterministic Fault Response: Hardware overcurrent, overvoltage, undervoltage, and overtemperature protection circuits operate independently of the DSP firmware. A hardware fault disables the IGBT gate drives within microseconds, before firmware can respond, preventing motor winding damage in fault conditions.
• DC Bus Sharing for Energy Recovery: Multiple S403M-PB units in the same cabinet can share a common DC bus rail. Regenerative energy from decelerating axes flows back onto the shared bus and is consumed by accelerating axes, reducing peak demand on the AC supply and lowering heat dissipation in the braking resistor.
• Resolver Feedback Option: For applications in high-vibration or high-temperature environments where optical encoders are unreliable, the resolver feedback option provides absolute single-turn position data without battery backup, using a transformer-coupled signal that is inherently immune to contamination and shock.
• Programmable I/O for Machine Sequencing: Seven digital inputs and three digital outputs, all 24 VDC logic, can be mapped to drive functions (enable, fault reset, speed preset select) or used as general-purpose I/O for machine interlock logic, reducing the I/O count required on the upstream PLC.
• Wide Motor Compatibility: Motor parameters (pole count, back-EMF constant, stator resistance, stator inductance) are entered via DRIVE.EXE, allowing the drive to operate with KOLLMORGEN AKM, Goldline, and compatible third-party AC brushless servo motors without hardware modification.
• Compact 60 mm Panel Footprint: The narrow profile allows multi-axis installations to be housed in standard 600 mm wide control enclosures without requiring custom cabinet widths, reducing enclosure cost and installation space.

Quality Assurance & Global Logistics

Every KOLLMORGEN SERVOSTAR 403M-P S403M-PB unit supplied by siemensplc.com is sourced through verified industrial channels and subjected to a structured incoming inspection protocol. Each drive undergoes visual examination for physical damage, power-on functional test under no-load conditions, parameter readback verification via DRIVE.EXE to confirm firmware integrity, and output current measurement to validate the analog and PWM stages. Units that do not pass all inspection criteria are quarantined and not listed for sale.

A 12-month warranty is provided from the invoice date, covering functional failures under normal operating conditions. Warranty claims are processed through [email protected] with a target response time of one business day. Replacement units are dispatched from Xiamen, China, with express freight options available for time-critical production line situations.

Logistics operations are based in Xiamen, Fujian Province, China — a major export hub with direct access to international freight carriers including DHL Express, FedEx International Priority, UPS Worldwide Express, and sea freight consolidation services for bulk orders. Standard export documentation (commercial invoice, packing list, certificate of origin) is provided with every shipment. HS code classification and customs value declaration are handled by our logistics team to minimize clearance delays at destination ports. Typical transit times: 3–5 business days to Europe and North America via express air freight; 7–14 business days via economy air; sea freight available for orders exceeding 50 kg.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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