SimpleIO - TriacOut Board Notes

DESIGN NOTES

Design Center » TriacOut Board Notes

These are notes from the layout of the TriacOut pc boards. This started with the TriacOut4, then made some changes for the TriacOut8 and TriacOut12 boards.

This is meant to be a general discussion, but assumes some basic electrical knowledge. We assume no liability for any content here, or what you do with it; experiment at your own risk, and with low voltages. Please let me know if you have any corrections or suggestions.


TriacOut4 Board Fabrication Drawing View larger View/Download huge	TriacOut4 Board Assembly Drawing View larger View/Download huge


TriacOut8 Board Fabrication Drawing View larger View/Download huge	TriacOut8 Board Assembly Drawing View larger View/Download huge


TriacOut12 Board Fabrication Drawing View larger View/Download huge	TriacOut12 Board Assembly Drawing View larger View/Download huge

The links above are various versions/sizes of the board drawings. Please keep the company and copyright information intact.
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For your convenience, I've collected the schematic, board, assembly, and bill of material into one PDF file for each board.
These packages are on the schematic design pages:
   TriacOut4 Schematic Notes
   TriacOut8 Schematic Notes
   TriacOut12 Schematic Notes

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Layout

Board

Triacs on one edge for heat sink.
Connectors on other edge for AC all together.
Fuse on end, and 5x20 mm, just for space.
Bottom right mounting hole drove the ACin connector to left.

DCin positioned to expand with channels.
- Pin 1 (+5) and 2 (unused, placeholder for gnd) always in same place.
- Pin 3 = In 1, etc.
- Room for 8 easily, 12 tight, no space for 16 (could have jammed J1 to the top, but would make the < 16 channels ugly).
- 12 or 16 could be 2-row connectors.
- Remove lower left mounting hole as needed (use a bumper or nylon spacer – recommend nylon spacers anyway, for proximity to AC).
- 2^nd mounting hole on bottom is in case bottom left is missing.

Opto-to-pullup resistor space is wide to allow horiz traces. 16 channel may need another board layer.
Input horiz traces use a via to make all channels symmetrical, even if not needed. Vias are offset from destination pin to sit between opto pins. Traces on bottom to be able to be cut, just in case.

VacIn seems reversed, but:
- H,N,H,N pattern is consistent.
- 4-pin stays below its two triacs, in the 'channel' (reversing to N,H would move 4-pin to the left too far).

Mounting holes are 5/16, from past boards. Positioned 0.2 in from corner, just for a round decimal number, and 0.25 was too far.
Found mini resistors for 0.2 grid, for trace spacing.
MOVs are 0.4 grid for space.
Vac traces at 0.050 wide. Do the heat calcs.

TriacOut8 Board Rev B

Lengthened board 0.5" for AC input connector, moving it up to the right of the fuse. 0.4" on the right, for an extra 0.1" on the left to separate inputs from channel 1 a little more.
Moved RJ45 jumpers up to top, to make room for input traces to get through.
Top and bottom input traces are just off grid from each other, to make it easy to see them on the two layers in Eagle.
Most of the little traces on 50 mil grid, so increased them to 12 mil.
Increased pad sizes.
Removed MOVs for space. Wire them into the connectors if needed.

Misc

Mount triacs with straight pinout to bend them over.
For rev A, moved the triacs even closer to the edge, so the tabs are just about flush with the board, for a large heat sink.
One vs. two strips of triacs – 12 might want 2x6 – would require two heat sinks.
Share Vdc In connector with pins on a ribbon-style connector.
If only 1 fuse, then it's not isolated. OK for typical use.
Run +5 to the pullup resistors along the top side, and drop down to each resistor on the bottom. This saves some horiz paths for the longer boards.

Connectors

Logic connector

Started with a terminal block, 0.1" centers (it's pretty small, but looks ok).
Need ability to wire the logic connector directly, or plug it into other logic or control boards.
Added separate right-angle square-pin header, for connecting to other logic or control boards.

Evolution: Would have liked a receptacle and terminal block in one connector. Did not want to replace the connector with yet more board options. A square-pin header could take a screw plug (sort of), but the screw plugs are very expensive. The additional square-pin header is very cheap, so added the connector, and grew the board 1/4".

Size: best if size can expand on this I/O board while logic connector can stay full size on the interfacing board (12 or 16). Else, this I/O always gets full size ($) or interfacing board has options for the connector (it may have options due to logic/drivers anyway).

J1, MPT06/254 package, drill was 0.047244. Increased drill to 0.05200 to match AC conn and fuse.

Added RJ45 connector and jumper block on TriacOut8 board (see schematic design discussion). It fit pretty well in the lower left corner. No board mounting hole in the corner, but next one is nearby.

The TriacOut12 connector uses most of the width of the board, nicely consistent with the other boards. There is no mounting hole in the lower left corner, but the next one is nearby.

AC input connector - TriacOut4, TriacOut12

Terminal block, 2-pin, 0.2" spacing for trace separation.
Wire the switched AC (hot) on left pin, common (neutral) on the right, to be consistent with outputs.
Locate on the far right.

AC input connector - TriacOut8

Header and plug, to be the same as the new output connectors.
Increased board length to locate connector on the right of the fuse.
2-pin, 0.2" spacing for trace separation.
Wire the switched AC (hot) on left pin, common (neutral) on the right, which is a natural layout on this rev, now that the connector is by itself

AC output connectors - TriacOut4, TriacOut12

Terminal block, 2-pins per channel, 0.2" spacing for trace separation.
Bring the common (neutral) to each channel, for easier wiring.
The 4-pin connectors are more cost-effective, so use them for 2 channels each. At 4 and up, the cost is linear per pin.
Start channel 1 on the left, and expand to the right, so channel 1 is consistent for all boards.

AC output connectors - TriacOut8

Plug-in style terminal block, 2-pins per channel, 0.2" spacing for trace separation.
Bring the common (neutral) to each channel, for easier wiring.
Located along the center of the board near the triacs. Vertical plug-in connectors guide the wiring directly off the board.
Start channel 1 on the left, and expand to the right, so channel 1 is consistent for all boards.

Sink/Source option

Create this with the two resistors and two test points.

The additional resistor went below the original one cleanly, and infringed on the MOV only a little bit. Nudged the MOVs down. The pattern in the opto and 2 resistors is a little complex, but it does repeat nicely.

See above for the assembly instructions.

AC traces

TriacOut4

Trying to get the traces wider (heat), but leave lots of space (UL).
Got traces to 50 mil, trying space of 100 mil; would like 125 mil.

For the triacs themselves, can always coat the leads for UL, rather than offset the pins. Or, since the pads are close anyway, may have to use the offset pin layout.
Surface mount can solve a lot of the spacing trouble. The pin won't be through to the bottom side.

Offset the traces to the MOVs on the bottom to run a 'leg' out to the MOV. It looks a little odd, but didn't want the AC going through the MOV pad.
Two of these pass right next to the MOV pad, and it always looks like a mistake (a short) at first glance. Have tried to move the trace farther over, but it's such a loop out of the way and back, it looks very strange. Leave it passing adjacent.
Similarly, added a little corner to the trace going to the triac 'through' the resistor. No room to push the resistor down without having to push the optos down even more.

Rotated the AC resistor so the pad is next to the triac pad, which helped some spacing.

TriacOut12

Changes made during TriacOut8 board Rev A, and carried to the TriacOut12.

Trying to get the traces wider (heat), but leave lots of space (UL).
Increase traces to 100 mil, which looks nice and wide. Trace width calculator has 47 mil for UL spacing, so change spacing limit to 50 mil. Lean toward higher current, less clearance, from the other boards being made out there.

With 100 mil, no longer need to offset the traces to the MOVs. Pass right through. The trace is wide to surround the pad. Might be good to fill the holes with solder if not installing MOVs.

The top MOV traces are not quite 45 deg. Channel 1 and 3 aim for the connector, and 2 and 4 just follow.

With 100 mil, also no longer needed to add a little corner to the trace going to the triac 'through' the resistor. The resistor pad is surrounded by trace.

Necked down the trace going to the middle triac pin to 60 mil. That's the size of the pad.
Increased the small triac traces to 20 mil, just because there's room.
Slid the gate trace over a bit, to run more in parallel with the adjacent wide trace.

TriacOut8 Board Rev B

Changes made during TriacOut8 Rev B board.

TriacOut8 Rev B groups the AC traces together with the opto output, connectors and triacs. This moves the DC traces to the edge of the board, further isolating them from the AC traces

Widened the AC traces to 120 mil, since there is space. Position the traces along the edge of the triac and connector pads, to maintain the spacing between the pads. Tried for 150 mil, to couldn't fit and maintain clearances.

Individual triac trace is 60 mil for a little bit, about 50 mil length, going into the pad. This is still good for 4-5 A.

Removed MOV for board space. With the plug-in connectors, it's easy to wire the MOV into the connector.