newbie questions

[omnivore]

I just received my ServoPod today. Very exciting - I have it up and communicating with my Linix box.

A few questions:

Are the various boards that use the JEDSTACK format compatible with the ServoPod? For instance, the servo and relay boards are bits I used in previous projects.

Is there a good tutorial on using timer pins to control servos? I'm starting small with three servos so I can use just the PWM pinsn now, but I'm aiming at a project that will use the full 26 servo control of the board. Any power supply issues anyone else has found for this many servos?

If I need to gang two or more servos together, is it any more complex than connecting them in parallel? The desired result is that a single channel sets more than one servo to the same position.

Finally, my searches on the forum were inconclusive re> using Linux terminal programs, but I seem to have no problems so far using Minicom which is part of Redhat 8.

TIA

dan donaldson

[RMDumse]

Originally posted by omnivore
Are the various boards that use the JEDSTACK format compatible with the ServoPod? For instance, the servo and relay boards are bits I used in previous projects.

No, there is no provision for adding boards from the JEDSTACK format. The Controller was so complete, we couldn't see adding anything else to the bus. It was difficult getting all the I/O pins that were there out to connectors, and still keep the board reasonably small.

The controller does a better job at servo control than the old servo control board. Go figure. We have sample programs that give the full trapezoid profiling capabilities of the NMIS-7056.

I can see where it would be nice to add relay boards, and peripherals of that nature. But it wasn't provided on the ServoPod(TM). It would still be possible to wire an adapter, and put the NMIS cards on port lines, and operate them that way. It's probably more trouble than it is worth.

Is there a good tutorial on using timer pins to control servos? I'm starting small with three servos so I can use just the PWM pinsn now, but I'm aiming at a project that will use the full 26 servo control of the board. Any power supply issues anyone else has found for this many servos?

The power from the board's supply will not be sufficient for more than a small servo or two without overloading. The rail supplying the servos, though, was intended to be feed directly from another power source. There's no direct connection from the rail to the internal power supply. The traces on the rail are rather hefty. The limitation might be the individual pins, though, as they are rated at 4A. So multiple connections could be used, and are spread through the servo connector banks.

I think the early walker code examples used direct manipulation of the timer registers. But now that the OO words have been added for control of the Timer PWM, they really are very easy to use to generate PWM. You'll probably want to use the OO words.

If I need to gang two or more servos together, is it any more complex than connecting them in parallel? The desired result is that a single channel sets more than one servo to the same position.

Ganging a few servos in parallel should be no problem. I've done it myself. There would be an upper limit to how many could be paralleled, but without knowing the load each servo draws, I can only speculate, but I'd guess 6 or 8 should be easily handled.

Finally, my searches on the forum were inconclusive re> using Linux terminal programs, but I seem to have no problems so far using Minicom which is part of Redhat 8.

You might find some problems later, when downloading stretches of source code. I think that is the only short coming of Minicom we know.