5.2.1 Front panels

The plate on the front of a module, or a blank that fills unused width in a row. It screws to the rails through a rail insert.

A front panel shall be no more than 2.0 mm thick (PANEL-004). EIS recommends 5052 aluminum or FR-4 circuit board, from 1.6 mm to 2.0 mm thick. FR-4 is less stiff, so an FR-4 panel needs extra mounting holes at a narrower width than aluminum (Annex J). The screw length window in 5.3 assumes a panel no thinner than 1.6 mm and keeps room for one up to 2.0 mm; a front panel thinner than 1.6 mm shall ship with mounting screws whose length fits that window for its own thickness (PANEL-014), since the enclosure's screws can bottom out through it.

A patch jack shall be a 3.5 mm mono (TS) socket (PANEL-005). 7.1 recommends insulating jacks from the panel.

A blank panel plays the panel role of 4.1 and meets the same height, width, thickness, and hole requirements as a module's panel.

Height

Format Panel height Hole span Holes from panel center Provenance
1U 39.65 mm 33.65 mm ±16.825 mm inherited: Intellijel 1U
3U 128.5 mm 122.5 mm ±61.25 mm inherited: Doepfer A-100

A 3U front panel shall be 128.5 mm high (PANEL-006). Three rack units are 133.35 mm, so a 3U panel is 4.85 mm shorter and sits in the 132.55 ± 0.4 mm aperture of 5.1. The 4.85 mm is clearance, not a rail lip; the lip EIS recommends, where a rail has one, is at most 1.5 mm (Annex A).

A 1U front panel shall be 39.65 mm high (PANEL-007), the Intellijel 1U format. That is 4.80 mm under one rack unit. EIS defines no other panel height.

Mounting holes shall be 3.0 mm in from the top and bottom panel edges (PANEL-008). The hole span is the panel height less 6.0 mm, 122.5 mm at 3U and 33.65 mm at 1U, and it shall be the same on the panel and between the inserts of a row's two rails (PANEL-009).

EIS · The 3U and 1U vertical budget, at one scale 3U = 133.35 panel 128.5 holes 122.5 board ≤ 110 3U 1U = 44.45 panel 39.65 holes 33.65 1U 3U panels are 128.5 mm (PANEL-006) and 1U panels 39.65 mm (PANEL-007); holes sit 3.0 mm in from each edge. A rail covers at most 9.25 mm of the panel face, and a board stays 9.25 mm clear of each edge (PANEL-012): grey is rail, blue is board.

Width

The nominal width of an N HP panel is N × 5.08 mm, where N is any positive whole number. An N HP panel shall be no wider than its nominal width (PANEL-002). EIS recommends making it 0.3 mm narrower, so that neighboring panels do not bind:

panel width = N × 5.08 − 0.3 mm

The board behind the panel is 0.6 mm under the nominal width (5.2.2). A rail is at least the nominal width of its row, so a row of panels at either width fits it.

EIS · Panel and board widths on the HP grid HP grid, 5.08 mm 4 HP 20.02 mm 20.32 nominal 8 HP 40.34 mm 40.64 nominal 2 HP 9.86 mm 10.16 nominal the joint, enlarged nominal edge panel board 0.3 mm 0.6 mm An N HP panel is no wider than N × 5.08 mm (PANEL-002). EIS recommends N × 5.08 − 0.3 mm, so that neighbors do not bind; the board behind it is N × 5.08 − 0.6 mm. Panels sit on the HP grid wherever they are in the row: each is centered between its nominal edges, so the clearance splits evenly between neighbors. The joint is drawn about 25 times larger than the row.

HP Nominal (mm) Panel (mm) Board (mm)
1 5.08 4.78 4.48
2 10.16 9.86 9.56
3 15.24 14.94 14.64
4 20.32 20.02 19.72
6 30.48 30.18 29.88
8 40.64 40.34 40.04
10 50.80 50.50 50.20
12 60.96 60.66 60.36
14 71.12 70.82 70.52
16 81.28 80.98 80.68
18 91.44 91.14 90.84
20 101.60 101.30 101.00
24 121.92 121.62 121.32
28 142.24 141.94 141.64
32 162.56 162.26 161.96
36 182.88 182.58 182.28
42 213.36 213.06 212.76
84 426.72 426.42 426.12
104 528.32 528.02 527.72

Mounting holes

Mounting holes shall be drilled Ø3.2 mm, or slotted 3.2 mm wide and no longer than 5.5 mm along the rail, centered on the hole position (PANEL-010); either clears the M3 mounting screw, and a short slot takes up the position error of a rail without letting the panel drop.

Along the rail, each mounting hole shall be a whole number of HP plus 2.54 mm from the panel's nominal left edge (PANEL-011). The nominal edges are N × 5.08 mm apart and centered on the panel, so every hole meets a hole in the rail insert, whatever the panel's width and wherever it sits in the row. Measured from the panel center, the holes of an odd-HP panel are a whole number of HP out, and those of an even-HP panel a whole number of HP plus 2.54 mm. The outer hole is 7.62 mm in from each nominal edge, except that a 1 HP panel has one hole on its center and a 2 HP panel has its holes at ±2.54 mm. Each rail gets the same row of holes.

EIS · Mounting holes from 1 to 8 HP, over one rail insert 1 HP center 2 HP ±2.54 3 HP center 4 HP ±2.54 6 HP ±7.62 8 HP ±12.7 rail insert: a hole every 5.08 mm, 2.54 mm in from each HP boundary Each hole is a whole number of HP plus 2.54 mm from the panel's nominal left edge (PANEL-011), so it meets an insert hole wherever the panel sits in the row. Holes are drilled Ø3.2 mm (PANEL-010) and are 3.0 mm in from the top and bottom edges (PANEL-008). Under each width: the hole positions from the panel's center, in millimeters. The outer hole is 7.62 mm in from each nominal edge; a 1 HP or a 3 HP panel has one hole on its center, and a 2 HP panel has its holes at ±2.54 mm.

The cards show an 8 HP panel. Each dimension runs from the panel center to one hole; the other three holes mirror it.

EIS · 3U front panel ±12.70 mm ±61.25 mm 0 3U front panel 8 HP 40.34 × 128.50 mm holes measured from the center ±12.70 mm along the rail ±61.25 mm up the panel drill Ø3.20 mm the other holes mirror the center

EIS · 1U front panel ±12.70 mm ±16.825 mm 0 1U front panel 8 HP 40.34 × 39.65 mm holes measured from the center ±12.70 mm along the rail ±16.825 mm up the panel drill Ø3.20 mm the other holes mirror the center

Four holes are the usual pattern. How wide a panel can be on four screws before it flexes under a plug, and where to add holes on a wider one, is in Annex J.

The numbers are in data/module.json. tools/module.py derives the hole spans and widths, computes the hole patterns of Annex J, and draws these cards.