In today's highly automated industrial field, high-performance and highly reliable servo drive systems are the core of achieving precision motion control. The SERVOSTAR 300 (S300) series digital servo amplifier from Kollmorgen, as a mature product that has undergone multiple iterations and verifications, integrates advanced driving technology, rich interface options, and critical safety functions. It is widely used in various demanding motion control scenarios. This article is based on its official manual, providing a systematic review and in-depth analysis of its technical essence, safety standards, installation points, and application configurations.
Product Overview and Core Positioning
The S300 series is a digital servo drive family launched by Colmorgen, covering standard versions with rated currents ranging from 1.5A to 10A. This series is mainly divided into two voltage levels:
S3xx6 type (such as S303, S306, S310): suitable for wide range single-phase/three-phase power supply from 110V to 230V AC.
S3xx0 type (such as S341, S343, S346): suitable for three-phase industrial power grids ranging from 208V to 480V AC.
Its design complies with overvoltage category III (according to EN 61800-5-1) and can be directly connected to grounded TN or TT power grid systems. The driver integrates B6 bridge rectifier, input filter, and soft start circuit, and supports single-phase power supply operation (such as for debugging phase).
The core features include:
Integrated safety function: Standard safety torque off (STO) function, compliant with SIL CL 2 (IEC 62061) and PLd (ISO 13849-1) safety levels, providing functional safety restart interlock.
Powerful communication capability: onboard CANopen interface (default 500 kBaud), with reserved expansion card slots, supporting various mainstream fieldbuses such as PROFIBUS, SERCOS, EtherCAT, DeviceNet, SynqNet, etc.
Multi feedback system support: fully compatible with traditional rotary transformers (Resolvers), sine encoders (Sin/Cos, supporting protocols such as EnDat, Hiperface, BiSS), incremental encoders (ROD), and modern single cable connection technologies (SFD3, HiperFACE DSL).
Intelligent control: Built in high-performance position controller, supporting electronic gears, master-slave synchronization, point-to-point positioning, and motion task sequence.
Dynamic braking and energy management: equipped with internal braking resistors, supporting external braking resistors or optional KCM (Colmorgen capacitor module) for energy recovery and storage, optimizing system energy efficiency.
Critical safety regulations and STO functionality
Safety is the cornerstone of drive system design. The S300 manual extensively emphasizes the safety operation guidelines.
1. General safety guidelines:
Professional personnel operation: Transportation, installation, commissioning, and maintenance must be carried out by professionals with electrical engineering qualifications.
Automatic restart risk: If the parameter AENA is set to 1, the drive may automatically restart after power is restored. A "power on automatic restart" warning sign must be set on the device, and it must be ensured that personnel cannot power on when in a hazardous area.
High voltage hazard: There is a voltage of up to 900V inside the equipment. After a power outage, the dangerous voltage of the capacitor may remain for up to five minutes. Before operation, all power sources must be cut off, wait for at least five minutes, and measure the DC bus voltage to confirm it is below 50V.
Leakage current: According to IEC 61800-5-1, the leakage current of the protective earth (PE) may exceed 3.5mA. Therefore, PE connections must use cables with a cross-sectional area greater than 10mm ² or adopt double line parallel connection.
Unauthorized modification is prohibited: Any unauthorized modification by the manufacturer will result in the invalidation of warranty and all certifications.
2. In depth analysis of the Safety Torque Off (STO) function:
STO is a core safety function of S300, aimed at safely removing motor torque to prevent accidental restart of the drive shaft and protect personnel safety.
Safety level: Single channel design, certified to PLd (ISO 13849-1) and SIL CL 2 (IEC 62061), with an average probability of hazardous failure (PFH_D) of 1.50E-07/hour and a mission time (TM) of 20 years.
Working principle: By disconnecting the 24V DC safety signal connected to the X4/5 terminal (STO Enable) of the driver, the internal electronic circuit of the driver will immediately cut off the energy supply to the motor, causing the motor to enter a torque free state.
Key safety instructions:
Non electrical isolation: STO does not provide electrical isolation for power output terminals. If you need to touch the motor power terminal, you must cut off the main power and wait for discharge.
No braking capability: When STO is activated, the driver cannot provide any braking torque. For vertical suspended loads, an additional safe and reliable mechanical brake must be equipped.
Prohibited as emergency shutdown or maintenance isolation: In case of prolonged shutdown, maintenance or emergency power outage, the main switch should be used to cut off the entire system power supply.