Serad PMA 628 Replacement Solution for PMA Series

Product Overview

Serad PMA 628 Replacement Solution for PMA Series: Smooth Transition & Legacy System Compatibility

The Serad PMA 628 is a multi-axis motion controller from Serad’s proven PMA Series platform, widely deployed in precision motion, CNC, and industrial automation systems across Europe and Asia. As legacy PMA Series controllers reach end-of-life or become increasingly difficult to source, many facilities are now planning structured replacements or direct drop-in upgrades to maintain production continuity. TOPNLMS maintains verified stock of the PMA 628 to support both emergency replacement and planned migration projects.

Whether your existing system runs a PMA 620, PMA 624, or an earlier multi-axis variant, the PMA 628 is engineered to integrate within the same control cabinet footprint. Its axis command architecture, encoder feedback interfaces, and analog/digital I/O pinout are designed for backward compatibility within the PMA Series family, significantly reducing rewiring effort during changeover. Engineers familiar with the PMA platform will find the programming environment and parameter structure consistent with prior generations, allowing existing motion programs to be adapted rather than rewritten from scratch.

During a typical retrofit, the PMA 628 is installed alongside or in direct replacement of the legacy controller. The unit accepts standard differential encoder signals and supports both RS-232 and RS-485 communication interfaces, making it compatible with upstream supervisory systems, HMI panels, and SCADA hosts that were originally configured for earlier PMA Series hardware. If your control cabinet uses a Serad PMA power supply module or a dedicated PMA axis expansion board, these components typically remain in service without modification, preserving your existing cabinet layout and reducing downtime during the transition.

For facilities integrating the PMA 628 into a broader automation architecture, the controller is commonly paired with Serad servo drive units compatible with the PMA command interface, as well as terminal block wiring modules that simplify field connections during installation. In multi-axis configurations, the PMA 628 coordinates with PMA Series I/O expansion modules to handle additional digital inputs, limit switch signals, and home position sensors without requiring a separate I/O controller. Where communication with a host PLC or DCS is required, a fieldbus gateway module supporting PROFIBUS-DP or Modbus RTU can bridge the PMA 628 to the plant network, preserving existing communication topology.

Physical installation follows the standard DIN-rail or panel-mount configuration used across the PMA Series. The PMA 628’s connector layout is consistent with earlier models, and in most cases the existing cable harness can be reused with minor pin verification. Where axis count or I/O requirements have grown since the original installation, a PMA Series backplane expansion rack can be added to accommodate additional modules without redesigning the cabinet structure. Commissioning typically involves parameter upload from the legacy unit, axis tuning verification, and a supervised test cycle — a process that experienced PMA engineers can complete within a standard maintenance window.

For systems where the original PMA 628 or its predecessor has been discontinued by the OEM, TOPNLMS sources units through verified industrial distribution channels and subjects each unit to functional testing prior to dispatch. This ensures that replacement stock performs to original specification and is ready for immediate installation upon arrival. Units are shipped from our Xiamen warehouse with full documentation, and each order is covered by a 12-month warranty against manufacturing defects and functional failure.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful PMA 628 migration rarely involves the controller alone. In practice, the upgrade process touches several interconnected components within the control cabinet and the broader automation system. The PMA Series power supply module that feeds the legacy controller is typically retained, as the PMA 628 operates on the same 24 VDC rail. Where the existing power module is aging or undersized for an expanded axis count, a replacement Serad PMA power supply of equivalent or higher current rating is recommended as a concurrent upgrade.

Wiring termination is simplified by using PMA-compatible terminal block modules, which allow field cables to be connected and labeled without modifying the existing cable harness. For axis feedback, the existing differential encoder cables connecting servo motors to the legacy controller are reused directly with the PMA 628, provided cable shielding and grounding are verified during commissioning. In systems where additional digital I/O is required — for example, to handle more limit switches, proximity sensors, or output relays — a PMA Series digital I/O expansion module can be added to the rack without structural changes to the cabinet.

Communication integration is handled through the PMA 628’s onboard RS-485 port, which connects to the plant network via a Modbus RTU to PROFIBUS-DP gateway or directly to a supervisory PLC or SCADA system. In facilities where an HMI panel was previously connected to the legacy PMA controller via RS-232, the same serial connection is maintained with the PMA 628, preserving the operator interface without reprogramming. For multi-cabinet installations, a fiber optic serial converter may be used to extend the RS-485 bus across longer distances while maintaining signal integrity.

Finally, where the legacy system included a Serad programming cable or USB-to-serial adapter for parameter upload and diagnostics, the same cable is compatible with the PMA 628, allowing engineers to use existing tools for commissioning and ongoing maintenance. This continuity across peripheral components — power, I/O, communication, and programming tools — is what makes the PMA 628 the preferred replacement choice for facilities already invested in the PMA Series platform.

Retrofit Guidance FAQ

Q: Can I reuse my existing wiring harness when replacing a PMA 620 or PMA 624 with the PMA 628?
A: In most cases, yes. The PMA 628 uses the same connector types and signal pinout as earlier PMA Series controllers. A pin-by-pin verification against the PMA 628 wiring diagram is recommended before powering up, but full harness replacement is rarely necessary.

Q: Will my existing motion programs run on the PMA 628 without modification?
A: Programs written for earlier PMA Series controllers are largely compatible with the PMA 628. Minor parameter adjustments may be required for axis scaling or acceleration limits if the new unit is configured for a higher axis count. TOPNLMS recommends a supervised test cycle before returning the system to production.

Q: Is the PMA 628 compatible with PROFIBUS-DP or Modbus RTU networks?
A: The PMA 628 communicates natively via RS-232 and RS-485 (Modbus RTU). Integration with PROFIBUS-DP networks requires a gateway module. TOPNLMS can advise on compatible gateway options based on your network topology.

Q: Does the PMA 628 fit in the same cabinet space as the legacy controller?
A: Yes. The PMA 628 uses the same DIN-rail or panel-mount form factor as the PMA Series family. No cabinet modification is required for a direct replacement. Expansion modules can be added to the existing rack if additional I/O or axis capacity is needed.

Q: What is the lead time for the PMA 628 from TOPNLMS?
A: Units in stock ship within 1–3 business days from our Xiamen warehouse. For urgent replacement requirements, please contact us directly at [email protected] or +86 18359293191 to confirm availability and arrange expedited dispatch.

Q: How is the PMA 628 tested before shipment?
A: Each unit undergoes functional testing prior to dispatch, including power-on verification, communication interface check, and axis command response testing. A test report is available upon request.

Warranty Assurance

Every Serad PMA 628 supplied by TOPNLMS is covered by a 12-month warranty from the date of shipment. This warranty covers manufacturing defects, functional failure under normal operating conditions, and communication interface faults. Units that fail within the warranty period are replaced or repaired at no additional cost to the buyer, with priority processing to minimize production impact.

Prior to shipment, each PMA 628 is subjected to a multi-point functional test: power supply verification, encoder interface continuity, RS-232/RS-485 communication handshake, and axis command response. Units that do not pass all test criteria are quarantined and not dispatched. This pre-shipment inspection process ensures that the unit you receive is ready for immediate installation.

For after-sales support, TOPNLMS provides technical assistance via email and phone throughout the warranty period. If a compatibility issue arises during installation — for example, a wiring discrepancy or a communication configuration question — our technical team is available to assist with diagnosis and resolution. Replacement units for warranty claims are dispatched from stock, typically within 2 business days of claim approval, to ensure that production downtime is kept to a minimum.

Procurement teams can request a formal warranty certificate, test report, and certificate of origin for each PMA 628 order. These documents support incoming inspection processes and quality management system requirements at the buyer’s facility.