Siemens 39SDM024DCCBN Replacement for APACS+ Series

Product Overview

Siemens 39SDM024DCCBN Replacement for APACS+ Series: Seamless Migration & Smooth Transition

The Siemens 39SDM024DCCBN (Part No. 16101-174/8) is a 24 VDC Discrete Output Module engineered for the APACS+ Distributed Control System platform. As Siemens has progressively phased out the APACS+ product line in favour of the SIMATIC PCS 7 and SIMATIC S7-400 ecosystems, many process plants, chemical facilities, and power generation sites are now facing urgent replacement and migration decisions. This listing provides a verified, tested, and immediately shippable replacement unit to support your control system continuity with zero compromise on signal integrity or rack compatibility.

Compatibility Comparison Table

Seamless Upgrade Solutions

A successful APACS+ migration rarely involves a single module swap. In practice, engineers replacing the 39SDM024DCCBN will typically audit the surrounding rack assembly at the same time. The APACS+ I/O carrier board and backplane must be confirmed serviceable before the new discrete output module is seated. If the carrier shows signs of corrosion or connector wear, a replacement APACS+ I/O carrier should be sourced concurrently to avoid a second outage window.

On the power supply side, the APACS+ 24 VDC system power module — often a Moore Industries or Siemens-branded redundant PSU — should be load-tested before commissioning the new output module. A marginal power supply that was previously masked by a failed output module can cause nuisance trips on the replacement unit. We recommend verifying the APACS+ power supply module output under full I/O load prior to final sign-off.

For sites migrating from APACS+ to SIMATIC PCS 7, the 39SDM024DCCBN is frequently used as a bridging solution during phased cutover. In this scenario, the SIMATIC ET 200M remote I/O station with SM 322 digital output modules is the target architecture, and the APACS+ discrete output module continues to serve legacy loops until the new PCS 7 AS 410 controller takes over. The PROFIBUS DP communication module installed in the ET 200M rack must be configured to match the existing field device addresses to avoid loop numbering conflicts during the transition.

Where the control cabinet also houses APACS+ analog I/O, the 39ADM024DCCBN analog input module and 39AOM024DCCBN analog output module are common co-residents in the same rack. Replacing the discrete output module while leaving aging analog modules in place is a valid interim strategy, but a full rack audit is advisable to identify any modules approaching end-of-life simultaneously. Signal isolators — particularly DIN-rail-mounted galvanic isolators for 4–20 mA loops — should be inspected for drift if the cabinet has been in service for more than ten years.

For sites that rely on HART-enabled field instruments, the APACS+ HART multiplexer module provides pass-through HART communication over the existing 4–20 mA wiring. Confirming that the HART multiplexer remains functional after the discrete output module swap is a standard commissioning checklist item, as backplane bus activity changes can occasionally affect HART polling schedules.

Finally, the programming interface: APACS+ WorkShop software running on a dedicated engineering workstation is required to download the I/O configuration to the replacement module. If the site no longer maintains a licensed WorkShop workstation, TOPNLMS can assist with configuration file archiving and recommend compatible engineering PC setups. The APACS+ controller module — typically the ACM (Advanced Controller Module) — must remain online during the hot-swap procedure if the system supports redundant I/O scanning.

Retrofit Guidance FAQ

Q: Do I need to rewire the field terminal block when replacing the 39SDM024DCCBN?
A: No. The existing field terminal block (FTB) connects to the module via the APACS+ carrier board. The replacement module seats into the same carrier slot and the FTB remains undisturbed. No field wiring changes are required.

Q: Will my existing APACS+ WorkShop configuration download to the replacement module without modification?
A: Yes. The replacement unit uses the same hardware revision baseline. Your existing I/O configuration file can be downloaded directly from the WorkShop engineering station without any parameter changes.

Q: Is the 39SDM024DCCBN compatible with both simplex and redundant APACS+ controller configurations?
A: Yes. The module operates identically in simplex and redundant ACM configurations. Redundancy switchover behaviour is governed by the ACM, not the I/O module.

Q: What is the physical installation clearance requirement?
A: The module occupies a single APACS+ I/O slot (standard width). No additional clearance beyond the existing slot spacing is required. Cabinet door clearance should be verified if the original module had a front-panel indicator that the replacement unit also carries.

Q: Can this module be used as a long-term spare while we plan a full PCS 7 migration?
A: Absolutely. Many customers purchase one or two units as strategic spares to extend APACS+ system life during a multi-year migration programme. The 12-month warranty covers the spare period from date of shipment.

Warranty Assurance

Every 39SDM024DCCBN unit shipped by TOPNLMS undergoes a pre-shipment functional verification process that includes visual inspection, connector integrity check, and power-on self-test validation. Units are shipped in anti-static packaging with individual serial number documentation.

Our standard 12-Month Warranty covers manufacturing defects, functional failure under normal operating conditions, and DOA (Dead on Arrival) replacement. In the event of a warranty claim, TOPNLMS will issue a replacement unit within 5 business days of receiving the defective module. Return shipping for warranty claims is covered by TOPNLMS for orders above USD 500.

For urgent plant shutdowns or unplanned outages, expedited shipping via DHL Express or FedEx International Priority is available from our Xiamen warehouse, with typical transit times of 3–5 business days to most global destinations. Stock availability is confirmed at time of order. For large-quantity procurement or blanket purchase orders, please contact our sales team directly.

Contact: [email protected] | +86 18359293191

© 2026 TOPNLMS. All rights reserved. Original Source: https://topnlms.com