GenTiba = Gen7 + TB6560AHQ - project

I decide to build two separate pcb's for my Alfa project. 1st one is a motherboard based Gen7 electronic ans 2nd one is doublesided driver's pcb. Two pcb's 7x12,5 cm. Is a easy way to test many wariants of driver's electronic without change motherboard. Soon I will show my electronics (mobo is almost finished - waiting for Molex-24 and mosfets) and driver's pcb is under construction. Driver's pcb have enaugh place for heatsinks, has been designed using 5W ceramic resistors 0R16, dip-switches, molex-4pin power, and goldpins for motors. Two pcb's connected with 10 wire cable

In this solution is easy way to use driver's pcb with Sanguinololu - needs build only adapter 10-wire to stepstick's ports or plug wires directly inside sanuinololu's connectors

Edited 1 time(s). Last edit at 02/07/2012 02:51AM by codec.

Oh, yet another Gen7 with TB6560

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

here is my 1st one pcb - modified Gen7

Interesting idea to have a separate driver board. Might be a good compromize between all in one boards and modular stuff like Gen3 for those who want modularity that is. Are you going to leave the driver board separate once the design is finalized or integrate it back in?

Driver's pcb project in attachment (almost finished)

bryanandaimee: I want to leave my project with two separate boards. In future 2nd over 1st one

Edited 1 time(s). Last edit at 02/07/2012 02:14PM by codec.

I'd rather see this in a one board solution myself modular solutions drive up prices when it comes to connectors, however the modular solution may allow for using the original gen 71.31 pcb and just plug in some connector wires to from the pololu headers to the new toshiba driver board could come in handy, anyone ever think about designing a single plug-in replacement (where you have a slightly longer pcb that plugs right in to the pololu headers since the pololu side towards the edge of the board is the major current carrying one the far side could be used with jumper wires / thin traces (not much current going through this) furthermore it would make a transition easier all it would take would be to change the firmware on some of the electronics we use and well presto instant replacement boards. They would be longer and probably ugly but it would be in the realm of the possibilities and well a good transition from our dependance on a chip that uses smd components. the bigger surface area would allow for all throughhole components but well may need standoff's to ensure the toshiba header's stay in place. (PC plastic ones come to mind as an example.)
just asking terramir

I think 4 additonal connectors are not expensive, but have smallest, handy electronic, I want to build universal driver board for any reprap's electronics. Unfortunately TB's, 5W resistors etc are large elements My first gentiba's pcb was standalone, but I stop this project (ugly and big). And do not forget about heatsinks for TB's - is an important point

Gen7 and Sanguinololu have different stepstick's spacing of connectors, so is not possible to build universal plug-in electronic Wiring is only way (needs only builds cheap apapters)

Edited 1 time(s). Last edit at 02/08/2012 01:30AM by codec.

Quote

5W resistors etc are large elements

2W ones are sufficient, for RepRap purposes even 1W. See current sensing resistor vs. motor current vs. resistor wattage:

R	I	P
ohms	amps	watts
0.15	3.3	1.7
0.18	2.8	1.4
0.2	2.5	1.2
0.22	2.3	1.1
0.24	2.1	1.0
0.27	1.9	0.9
0.33	1.5	0.8
0.39	1.3	0.6
0.43	1.2	0.6
0.47	1.1	0.5
0.51	1.0	0.5
0.56	0.9	0.4
0.68	0.7	0.4
0.75	0.7	0.3
0.82	0.6	0.3
1	0.5	0.2
1.2	0.4	0.2
1.5	0.3	0.2
1.8	0.3	0.1
2	0.2	0.1

Also, avoid wire-wound resistors, as these have an inductivity.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

Traumflug thnx !!
In my nu project I want to use nema23 motors 2.2-2.8A

Edited 1 time(s). Last edit at 02/08/2012 11:02AM by codec.

Traumflug: speaking of power resistors do you know of a source for 1W .25 ohm (or .24) resistors that are not wire wound? Mouser seems to have only wirewound in resistances below .5 Ohm.

[de.mouser.com]
[de.mouser.com]
[de.mouser.com]
[de.mouser.com]
[de.mouser.com]

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

my first double sided pcb

Edited 1 time(s). Last edit at 02/12/2012 01:59PM by codec.

good work on the double sided pcb however shouldn't we focus on single sided if possible for the gen7 variations in order to let people be able to replicate?
terramir

For now I think a double sided PCB is fine. Routing traces for this chip isn't as easy as with the Pololus, so we likely need an iteration or two until the results are satisfying. The Toshiba has new challenges, for example there is no motor current trimpot possible (unless you find one with 2.0 ohms at 2 watts for a reasonable price).

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

how is the current being regulated by this chip your saying we have to go with a fixed current and change resistors if we change motors, I really didn't read that deeply in the data sheet yet
terramir

current and microstepping is regulated via pins/switches (6 pcs). You dont need to change resistors with motors change. Current options: 25% of 3.5A / 50% of 3.5A / 75% of 3.5A / 100% of 3.5A

True, but jumpers can switch between four currents, only. Designing the maximum current (100%) might be 1.5A or 2A, set by the resistors. With 1.5A we'd have 1.5/1.125/0.75/0.3A, sounds reasonable to me.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

work in progress

Edited 1 time(s). Last edit at 04/09/2012 06:13AM by codec.