Description
ELTEC PMCE-740 | Dual PMC Extension Board | BAB 740 VMEbus Computer
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | ELTEC Elektronik |
| Model | PMCE-740 |
| Board Type | PMC Extension Board |
| Host Computer | BAB 740 |
| PMC Slots | 2 |
| PMC Interface | PCI Mezzanine Card |
| VMEbus Role | Power and rear I/O routing |
| VME P1 Signals | GND, +5 V, +12 V |
| VME Data Signals on P1 | None |
| PMC I/O Routing | PMC connectors to VMEbus P2 |
| Power Connector | X403 |
| PMC Connectors | X101, X102, X201, X202 |
| P1 Connector | X402 |
| P2 Connector | X401 |
The ELTEC manual explicitly states that the PMCE-740 allows the BAB 740 to be expanded by two PMC modules. Its VMEbus P1 connection does not carry normal VMEbus data signals; GND, +5 V, and +12 V are routed to the PMCE-740 power connection.
The PMC interfaces provide the PCI/PMC signal set, including PCI address/data, control, clock, interrupt, and power signals. PMC rear I/O is routed through the PMCE-740 toward the VMEbus P2 connector, allowing installed mezzanine cards to expose their I/O through the host backplane.
Product Introduction
The ELTEC PMCE-740 is the PMC expansion board designed for the ELTEC BAB 740 PowerPC VMEbus computer. Its primary job is straightforward: provide two additional PMC positions while handling the required electrical connection and rear-I/O routing between the PMC cards and the BAB 740/VMEbus assembly.
This is a system-specific expansion board rather than a generic PMC carrier. For replacement work, the should be evaluated together with the BAB 740, the installed PMC cards, connector configuration, and rear-I/O wiring. Treating it as an independent VME I/O card can lead to an incorrect spare selection.
PMCE-740
Application Scenarios & Field Pitfalls — The Engineer’s Perspective
Engineering Pain Point
A legacy VME computer can remain operational for years until a relatively simple carrier or interconnect board becomes unavailable. With the , the risk is not just whether the replacement board powers up. The PMC slot assignment, rear-I/O routing, jumper configuration, and physical relationship to the BAB 740 all affect whether the complete assembly behaves as intended.
Typical Applications
- Expansion of ELTEC BAB 740 VMEbus computers with PMC peripherals
- Legacy industrial computer systems requiring additional PCI/PMC functionality
- Image-processing or data-acquisition systems using PMC mezzanine cards
- Industrial control and measurement systems built around the BAB 740 platform
- Replacement of damaged or failed carrier hardware
Technical Pitfalls
- Do not classify as a standalone CPU. The BAB 740 is the computer/CPU board; is its PMC expansion board.
- Two PMC positions are available. The documented connectors correspond to two PMC slots, with dedicated connector sets for each position.
- P1 is not a normal VMEbus data interface. The manual states that only power-related connections are routed from VMEbus P1 and that no VMEbus signals are used there.
- Rear I/O requires attention. PMC I/O is routed toward the VMEbus P2 connector. A PMC replacement with a different rear-I/O pin assignment can therefore create a system-level compatibility problem even when the PMC electrical interface itself is correct.
- The board is mechanically tied to the BAB 740 installation. ELTEC documentation notes that the BAB 740 requires two VMEbus slots when used with the PMCE carrier and that the two-board assembly should be installed or removed carefully as a package.
- Check jumpers before replacement. provides configurable routing associated with PMC interrupt request/grant signals. The manual documents jumper settings for PMC slot routing, so the jumper configuration on a failed board should be recorded before swapping it.
Related Products
- ELTEC BAB 740 — Host VMEbus PowerPC computer designed to work with the expansion board.
- ELTEC BAB-740/1 — BAB 740 board variant encountered in legacy equipment; verify revision and assembly configuration before substitution.
- ELTEC PMGrabber — PMC-based frame-grabber hardware documented for use with a BAB 740 and combination.
- PMC Modules — The provides two positions for PCI Mezzanine Cards; the actual application depends on which PMC devices are installed.
- ADAP-740 — BAB 740-associated adapter hardware used for selected peripheral interfaces.
Procurement Note
For a replacement, do not purchase by the model number alone when the system is critical. Record the BAB 740 revision, board revision, installed PMC cards, jumper positions, rear-I/O cable/backplane arrangement, and visible connector condition.
A used should also be checked for bent PMC connectors, damaged VME contacts, cracked solder joints around the board-to-board interface, and evidence of mechanical stress. The correct spare is the one that matches the complete BAB 740 assembly configuration, not simply a board with the same silkscreen designation.
