Four-bay modular bench instrument
Swap a module without stopping the measurement.
A scope front end, a logic analyser, programmable power and a generator, in one chassis. Each bay is electrically its own instrument. All four share one clock.
B4 chassis, bay 1 module withdrawn. Leads, probes and a bench supply, for scale.
00 · Front elevation, dimensioned
212 mm88 mm48 mmM3 x 8, 8 offBAY 1BAY 2BAY 3BAY 401 · The decision
The chassis is the product. The modules are the easy part.
Each bay runs from its own isolated DC-DC converter, so a short on bay 3 does not take bay 1 with it. One differential 10 MHz reference is distributed from the backplane to all four bays, so captures line up without software correction.
The connector is published under CERN-OHL-P v2. You can build a module we have not thought of, and it will clock with the ones we have.
02 · What is inside
Nine part groups, one explosion axis.
Bill of materials
| No. | Part | Qty |
|---|---|---|
| 01 | Bezel, milled 6082 | 1 |
| 02 | Module, bay 4 | 1 |
| 03 | Module, bay 3 | 1 |
| 04 | Module, bay 2 | 1 |
| 05 | Module, bay 1 | 1 |
| 06 | Bay carrier, extruded | 1 |
| 07 | Isolated DC-DC, per bay | 4 |
| 08 | Backplane, 4-layer | 1 |
| 09 | Shell, folded 1.5 mm | 1 |
Scroll to separate. Scroll back and the parts return to their seats.
03 · Rear panel
Trace any net to the bay it serves.
Eight BNC on the rear plate. Hover one to follow its path through the backplane. The 10 MHz reference is the only net that reaches every bay.
04 · Specifications
Property, value, method.
| Property | Value | Method |
|---|---|---|
| Bays | 4 | Mechanical |
| Bay pitch | 48 mm | Mechanical |
| Chassis | 212 x 88 x 240 mm | Measured |
| Mass, no modules | 2.4 kg | Measured |
| Reference | 10 MHz differential | Design |
| Inter-bay skew | See capture 04-A | Measured, raw capture |
| Bay isolation | 1 kV, bay to bay | Design |
| Supply, per bay | Isolated DC-DC | Design |
| Backplane | 4-layer, 1.6 mm | Mechanical |
| Connector | Published, CERN-OHL-P v2 | Licence |
Performance rows link a raw capture rather than a headline number. A figure with no method behind it is marketing.
05 · Open and repairable
Every fastener is an M3 cap screw.
- Connector specCERN-OHL-P v2
- FirmwareMIT
- Enclosure drawingsSTEP + DXF
- FastenersM3 x 8, 8 off
- Backplane sparesDistributor part number
There are no glued joints and no proprietary screws. The bezel comes off with one hex key, and the backplane is a stocked part.
06 · Batch one
140 chassis. No countdown.
The first run is 140 chassis with two module types. We will publish the connector before we ship, so a third party can start work without waiting for us.