Weidmuller 8708680000 Migration-Ready 24VDC PSU

Overview

Weidmuller 8708680000 Migration-Ready 24VDC PSU: Legacy Control System Retrofit and Upgrade

The Weidmuller 8708680000 is a ConnectPower series 24VDC DIN rail power supply engineered for direct integration into existing control cabinets, retrofit projects, and legacy automation system upgrades. As industrial facilities face increasing pressure to modernize aging infrastructure without full system overhauls, the 8708680000 provides a reliable, drop-in power solution that bridges the gap between discontinued hardware and current control architectures. Whether you are replacing an end-of-life PSU in a Siemens S5 or S7 control cabinet, upgrading a legacy Allen-Bradley SLC 500 panel, or retrofitting a Mitsubishi MELSEC rack-based system, the 8708680000 delivers stable 24VDC output with the terminal compatibility and DIN rail form factor required for minimal downtime changeovers.

Before initiating any power supply replacement in a live control environment, engineers must verify several critical parameters. Power capacity confirmation is the first step: calculate the total current draw of all connected I/O modules, communication modules, and field devices to ensure the 8708680000 output rating meets or exceeds the existing load. Terminal wiring compatibility must be checked against the original PSU’s L+, M, and PE terminal assignments — the ConnectPower series uses standard push-in or screw terminal blocks that align with most legacy wiring harnesses, but conductor cross-section and torque specifications should be confirmed before re-termination. Backplane interface requirements are not applicable for standalone DIN rail PSUs, but the physical installation space within the control cabinet must be measured to confirm the 8708680000 footprint fits the available DIN rail segment without displacing adjacent modules such as Weidmuller ACT20P signal conditioners or terminal block assemblies.

For systems incorporating Weidmuller u-remote or UR20 remote I/O stations, the 8708680000 can serve as the primary 24VDC supply feeding the power feed module, ensuring consistent voltage to distributed I/O nodes across PROFINET or EtherNet/IP communication links. When migrating from older fieldbus architectures such as PROFIBUS DP or DeviceNet, the power supply stability directly impacts communication link integrity — voltage ripple or transient drops during switchover can corrupt node addresses or trigger watchdog faults in connected PLCs. The 8708680000’s regulated output and wide input voltage tolerance make it suitable for facilities operating on variable mains quality, a common challenge in older manufacturing plants undergoing phased modernization.

During retrofit planning, the interaction between the power supply and adjacent components must be carefully mapped. In a typical control cabinet upgrade scenario, the 8708680000 may supply 24VDC to a combination of Weidmuller WP series terminal blocks, ACT20C signal isolators, and a Siemens ET 200SP distributed I/O station. The firmware version of the connected PLC or remote I/O head station should be verified for compatibility with the control program logic, particularly if the retrofit involves replacing a CPU module alongside the power supply. HMI screen configurations referencing power supply status bits or diagnostic alarms may require updates if the new PSU reports health data through a different diagnostic channel than the unit being replaced.

Installation space confirmation is essential in densely populated control cabinets. The 8708680000 DIN rail mounting profile should be compared against the original unit’s width and depth to avoid interference with cable ducts, adjacent breakers, or contactor assemblies. Once physically installed, on-site commissioning should include output voltage measurement under full load, inrush current verification during cold start, and a functional test of all downstream devices before returning the system to production. KNMKS pre-shipment testing protocols verify output voltage accuracy, load regulation, and terminal integrity on every 8708680000 unit prior to dispatch, supporting rapid field installation with minimized verification time.

Migration Compatibility Table

Retrofit Planning for Existing Automation Systems

A structured retrofit plan for the 8708680000 typically begins with a cabinet audit. Document all devices drawing 24VDC from the existing power supply, including Weidmuller u-remote UR20-4DO-4A output modules, ACT20P process signal conditioners, Siemens S7-1200 or S7-300 CPU expansion racks, and any third-party safety relays or solenoid valve drivers. Calculate the aggregate current demand and compare it against the 8708680000 rated output to confirm adequate headroom — a minimum 20% derating margin is recommended for industrial environments with variable ambient temperatures.

Terminal block reassignment should follow the original wiring diagram. Where legacy systems used older Weidmuller WDU or SAK series terminal blocks, the existing conductor assignments can typically be preserved without re-labeling, provided the conductor cross-section is within the 8708680000 terminal specification. For systems incorporating Weidmuller ACT20C signal isolators between field sensors and the PLC analog input modules, verify that the 24VDC auxiliary supply to the isolator loop power terminals is correctly routed from the new PSU output. Communication modules such as Weidmuller IE-SW-BL05 industrial Ethernet switches or PROFIBUS repeaters should be powered from a dedicated 24VDC branch protected by a Weidmuller MCZ OVP surge protection device to prevent transient damage during PSU switchover.

Downtime Control During System Migration

Minimizing production downtime during a power supply replacement requires pre-staging the 8708680000 on a bench test rig before the scheduled maintenance window. Confirm output voltage, load regulation, and terminal continuity offline. During the live changeover, isolate the 24VDC distribution bus using the existing main circuit breaker or a dedicated load disconnect terminal, then swap the PSU while preserving all field wiring connections. If the control system includes a Siemens S7 CPU with retentive memory, ensure the CPU is in STOP mode before removing power to prevent program data loss. After reconnection, power up sequentially — PSU first, then communication modules, then I/O stations — to allow the PLC to re-establish network topology before resuming scan cycle execution. HMI panels connected via MPI or PROFINET should automatically reconnect once the CPU returns to RUN mode, but manual acknowledgment of any pending alarms related to the power interruption may be required before releasing the system to operators.

Retrofit Support FAQ

Q: Is the Weidmuller 8708680000 a direct replacement for other ConnectPower series PSUs?
A: Yes. The 8708680000 is designed as a form-fit-function replacement within the Weidmuller ConnectPower family. Verify output current rating and terminal block type before installation to confirm compatibility with your specific cabinet configuration.

Q: What commissioning steps are required after installing the 8708680000?
A: Measure output voltage at the PSU terminals under full load, verify all downstream devices power up correctly, check for any PLC diagnostic faults related to the power interruption, and confirm communication link status on all connected network nodes before returning to production.

Q: Can the 8708680000 supply power to both digital I/O modules and communication modules simultaneously?
A: Yes, provided the total current draw of all connected devices does not exceed the rated output current. It is recommended to use separate 24VDC branch circuits with individual fusing for I/O modules and communication equipment to isolate fault conditions.

Q: What support terms and pre-shipment testing does KNMKS provide for the 8708680000?
A: Every 8708680000 unit shipped by KNMKS undergoes pre-shipment functional testing covering output voltage accuracy, load regulation, and terminal integrity. A support terms confirmed by quotation is included from the date of shipment, covering manufacturing defects and functional failures under normal operating conditions.

© 2026 KNMKS. All rights reserved.
Original Source: https://knmks.com
Contact: [email protected] | +86 18359268345

Product Identification

Brand / Ecosystem

Other Brands
Assorted Brands

Model / Series

8708680000
Assorted Series

Product Family

Power Supplies

Availability Status

Available on request after model and quantity confirmation

Inquiry Type

B2B RFQ, replacement inquiry and project spare-part request

Pre-Quote Check

Exact SKU, brand, series, quantity, nameplate photos and destination country are checked before quotation

Specification & Inquiry Focus

Power range

DIN rail and switching power supplies

Common needs

Voltage, current and mounting style

Project support

Control cabinet and panel-builder inquiries

Inquiry Support

• 24VDC and cabinet power selection support
• Stable power support for PLC and HMI systems
• Batch inquiry support for panel builders

What to Send Us

• Brand and exact model number: Other Brands 8708680000
• Quantity and required delivery time
• Application, replacement requirement or nameplate photo
• Destination country and shipping preference