Modernization of DCS and PLC with Electronic Marshalling

Now, with many control systems being 30+ years old, most of these legacy systems have been placed in to end of life or retired lifecycle status. This means no further factory support is available. I caught up with Emerson’s Scott Ross about some of the choices that must be considered moving forward.

Manufacturers and producers face options whether to modernize to a newer family of distributed control systems (DCSs) and programmable logic controllers (PLCs) or move the PLC I/O and logic to a DCS, such as the DeltaV DCS. For many users with legacy PLCs and DCSs, the ongoing challenge has been to decide what I/O solution to use in the migration project.

Many users have been very creative with the use of DeltaV Electronic Marshalling – CHARMs solutions. This approach locates the I/O out in the process, provides mounting options horizontally, vertically or both, communicates with the DeltaV communication backbone via fiber or copper, and enables the removal of 30-year-old intrinsically safe (I.S.) barriers by using the I.S. Electronic Marshalling – CHARMs. These provides both signal characterization and galvanic isolation for intrinsically safe applications.

Flexible 19-inch DeltaV Electronic Marshalling - CHARMs solutions

Flexible 19-inch DeltaV Electronic Marshalling – CHARMs solutions

Flexible 19-inch DeltaV Electronic Marshalling – CHARMs solutions for Basic Process Control System (BPCS) Migration and SIS Migration projects simplifies the legacy hardware conversion and enables flexible design & installation cost-savings.

These solutions offer the following advantages:

Flexible Footprint

  • 12 to 96 I/O per CHARMs I/O Card (CIOC) vs. 8, 16 or 32-channels for traditional I/O cards
  • Distributed CHARMs in grouping of 12 CHARMs in a star or ring topology
  • Mount upside-down or sideways in an existing rack, if necessary
  • Use in place of existing junction box or marshalling terminations
  • Copper Ethernet or fiber optic connections to the DeltaV Area Control Network

Environmental Flexibility

  • Class 1, Division 2; ATEX Zone 2; -40 to +70 degC
  • Mount indoors or out in the process

DeltaV CHARMs mounted in motor control center bucket

Flexible I/O Options (on a channel by channel basis)

  • 3 times the I/O coverage of other suppliers: 39 CHARMs–16 BPCS, 17 SIS, 6 I.S. and 14 terminal blocks cover most of the field wiring signals
    • Relay term blocks to handle high current applications
    • I.S. CHARMs (the only configurable I/O solution to offer I.S. in the same form-factor/space)
  • Single channel integrity and Field Termination Assembly functionality

Some additional “hidden” benefits of Electronic Marshalling include:

  • Cleaned up existing cabinets allowing for easier expansion/maintenance
  • Moved the CHARMs to the cabinets where the field wiring enters the plant, eliminating all the undocumented old troublesome home runs and termination cabinets
  • Removed external 3rd party “Retired” I.S. barriers; adding I.S. CHARMs with integrated barriers saved valuable cabinet space and time in re-wiring the barriers.
  • Risk avoidance and enabled better maintenance practices
    • Removing the common AC neutral, now each CHARM has a dedicated AC neutral.
    • CHARMs Diagnostics, Electronic Wiring Diagrams (DEWD) troubleshooting app available on iPhone and Android.
  • Removed larger height termination/marshalling panels and replaced them with 19-inch 3 EIA height horizontal CHARMs solutions, freeing up additional space in the existing cabinets.
    • The 19-inch horizontal Electronic Marshalling migration mounting solutions are available for the CIOC’s (Qty 2) and CHARM baseplates (Qty 2 – 12 CHARM baseplates = 24 CHARMs per panel)

Contact your local sales office or Emerson Impact Partner for more on the capabilities and delivery times on these modernization solutions or visit the Modernization & Migration section on You can also connect and interact with other modernization and DeltaV experts in the Services group and DeltaV forum in the Emerson Exchange 365 community.

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