Description
- Brand: Emerson Network Power
- Full Model Number: PMCSPAN
- System/Series Family: PowerPlus VME Embedded Computing
- Core Function: PCI expansion carrier for Emerson VME processor modules
- Top 3 Hardcore Specs: 6U single-slot VMEbus / 2 single-wide or 1 double-wide PMC / PLX PCI-to-PCI bridge
- PCI Standard: PCI Local Bus Specification Revision 2.1
- I/O Access: Front-panel and/or P2
- Expansion Capacity: Up to 6 PMCs with compatible stacked configuration
- Stock Status: New Surplus — exact variant and condition to be verified
Commercial-Technical Deep Dive
A VME processor may still have adequate CPU resources while its available PMC capacity becomes the limiting factor. Emerson PMCSPAN addresses that constraint by adding PCI-based PMC expansion to compatible PowerPlus VME processor boards. The PMCspan itself is a 6U single-slot VME-format module linked to the host processor through a PCI expansion connector. Each carrier accepts either two single-wide PMCs or one double-wide PMC, with front-panel and P2 I/O supported.
The important specification is expansion topology, not processor speed. One PMCspan adds two single-wide PMC positions, while compatible stacked arrangements can add up to four more single-wide PMC positions to the host processor platform. The design uses a PLX PCI6150 PCI-to-PCI bridge and complies with PCI Local Bus Specification Revision 2.1. For legacy control, test, data-acquisition, and communications systems, this architecture can preserve an existing VME CPU while adding the required PMC interfaces rather than replacing the complete processor platform. (Actual stacking depends on the host VME board and PMCspan variant.)
Compatibility & Installation Traps
Migration/Compatibility
PMCSPAN is not a universal VME plug-in replacement. It is a PMC carrier designed for compatible Emerson PowerPlus VME processor modules. Published documentation identifies specific PMCspan variants for host boards such as the MVME5100 and MVME5500 families. The primary and secondary PMCspan versions are not interchangeable because their mechanical and PCI functions differ.
A same-variant replacement normally does not require a control-logic rewrite. However, the host processor, PMCspan primary/secondary configuration, PMC type, I/O routing, and mounting hardware must match the original system arrangement. Verify the exact suffix before ordering; PMCSPAN alone does not identify every hardware variant.
⚠️ Field Traps (Watch Out)
- Wrong primary/secondary carrier: Primary and secondary PMCspan versions have different functions. A secondary unit relies on a compatible primary carrier and cannot simply substitute for it.
- Powered installation: Emerson documentation warns that inserting or removing modules with power applied can damage components. Follow full system power-down and ESD procedures before installation.
- Mechanical clearance: PMCspan mounts onto the host VME processor using specific expansion connectors and standoffs. Confirm connector alignment before tightening hardware.
Emerson PMCSPAN
Quality Assurance SOP
Our inspection protocol for PMCSPAN inventory should focus on the board, expansion interface, and host compatibility.
- Part-number verification: Record all visible PMCSPAN model and revision markings.
- OEM anti-counterfeit visual inspection: Check PCB markings, labels, connectors, bridge-device identification, mounting hardware, and manufacturing details.
- PCB condition inspection: Examine solder joints, connector contacts, PCB surfaces, mounting points, and components for corrosion or physical damage.
- PCI bridge verification: Confirm the expected PLX bridge device is present where applicable to the documented variant.
- PMC connector inspection: Check both PMC positions for bent contacts, contamination, mechanical damage, and abnormal wear.
- Host-interface inspection: Verify the PCI expansion connector and mounting interface against the applicable host-board configuration.
- Power-on validation: Install in a compatible test platform where available and check for abnormal diagnostic indications.
- Communication verification: Confirm the host system can enumerate the PMC expansion path and recognize an installed test PMC.
- I/O verification: Test front-panel or P2 routing when the applicable PMC and test chassis support it.
- ESD packaging check: Return the board to antistatic packaging immediately after testing.
Published installation guidance specifically calls for ESD protection and warns against energized insertion or removal.
CRO-Driven Buyer FAQ
Is Emerson PMCSPAN obsolete?
The PMCspan belongs to Emerson’s legacy PowerPlus VME embedded-computing architecture. Current sourcing therefore depends heavily on remaining inventory and compatible replacement stock. Confirm the exact suffix before purchasing because several PMCspan variants exist.
How many PMC cards can one PMCSPAN support?
A single PMCspan supports either two single-wide PMC modules or one double-wide PMC module. With compatible stacking, the overall Emerson processor configuration can support additional PMC positions, reaching up to six PMCs in the documented architecture.
Can PMCSPAN be hot-swapped?
Do not treat it as a hot-swap module. Emerson installation documentation states that inserting or removing modules while power is applied may cause component damage. Use the prescribed power-down and ESD handling procedure.
Does PMCSPAN work with any VME CPU?
No. Compatibility is host-specific. Emerson documentation identifies PMCspan configurations for compatible PowerPlus VME processor families, including specified MVME5100 and MVME5500 platforms. Verify the host connector, primary/secondary designation, and PMC requirements
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