Electrolytics generally have more leakage current than ceramic or tantalum which may cause a bit of inaccuracy with high resistance thermistors. With a 10K thermistor I don't think you will notice. They also tend to have worse tolerances but I think the value of the capacitor gets calibrated out. You can get ceramic up to 20uF but they get pricey and may only be surface mount. I found this in tby nophead - Controllers
Eric, Yes it makes the problem clear, sorry I don't know what the solution is as I am not familiar with the official firmware / software yet. Odd that there should be an AngleSpeedFactor property though. I just use Pythagoras' theorem to correct the diagonal speed on my machine. Chrisby nophead - Controllers
Do you mean the straight line speed drops as the motors should slow down when doing a diagonal to keep that constant?by nophead - Controllers
It's only a rectangular block with about a dozen objects subtracted from it, cylinders and blocks. I wouldn't have thought that was "big and nasty" but I have no experience of 3D cad. It must be hard to burn up 2 minutes of CPU time these days but then it is written in Javaby nophead - RepRap Host
AOI takes nearly 2 minutes to open clamp.aoi on my system which is an Athlon XP2800. During this time the application does not respond and there is no progress bar. This seems ridiculous for such a simple model. Is this typical or is there something peculiar to my installation?by nophead - RepRap Host
Ah yes. I hadn't looked at the code as I am not using it so I had assumed full stepping used both coils as that is the convention. If torque is not an issue then using one coil will keep the motors cooler. Of course torque falls off with speed so using one coil instead of two limits the top speed. Again that is probably not an issue with belt drive as the extruder speed is probably the limitingby nophead - Mechanics
Dan P. Wrote: ------------------------------------------------------- > N.T. if there is the expectation to microstep > these motors down stream, then we need to be a > little careful as microsteps don't provide the > same torque as full steps. No and neither does half stepping so anybody using 200 step motors needs to bare that in mind.by nophead - Mechanics
Blerik, I think there are some problems with your calculations. 100 KHz / 400 steps is 250 revs per second or 15000 RPM which is way too fast for a stepper motor. To get reasonable speed with a lead screw you need to use one designed for the job. These are multistart, have a big pitch and are relatively expensive. As an example my machine uses ball screws with a pitch of 1/2" and 200 step motby nophead - Reprappers
Presumably curing with electron beams would require the liquid to be in a vacuum?by nophead - Laser Cutter Working Group
I just remembered I have 14 20 inch colour monitors in my loft. Probably a bit low on voltage and current at that size though, but I could parallel them up for more current.by nophead - Laser Cutter Working Group
I think 25KV at a few milliamps is about the spec of the EHT circuit of a large CRT television, and the circuit you describe is pretty much how a TV does it. I expect a lot of these are being replaced by LCD and plasma currently so it might be something fairly easy to get hold of. You do have to be careful with X-ray emission at these voltages, not sure if lasers are affected but CRTs and valvesby nophead - Laser Cutter Working Group
Studding is only used on the z-axis. The other two use timing belts so are much lower resoltion but faster moving.by nophead - Reprappers
I think the way I would handle this is to have the head return an identifer, possible a string or integer id, and the use that in the host s/w to load a plug-in of some sort. A bit like when you plug in a USB device and the OS loads a driver. That keeps the PIC firmware as simple as possible. The only complication to the host s/w is to create some sort of abstract interface to a head controller.by nophead - Reprappers
Simon McAuliffe wrote: > It's OK. But it is encumbered by one overriding and crippling original > design decision: that code blocks should be decided purely by > indentation. I originally considered Python for RepRap, but the > indentation thing is so utterly dumb (just like tabs in Makefiles) that > I voted against it. I think this is one of the great things about Python. I agreeby nophead - RepRap Host
Comms errors while the motors are running are likely to due to noise. You are using higher current motors than the standard RepRap so ground bounce may be an issue. Make sure you have thick (pref 32/0.2) ground wires from the power board to the driver boards and keep them as short as possible. Although the comms is a ring, the power should be a wired as a star. Whereas the steppers are lilelyby nophead - RepRap Host
I don't think bad connections are to blame because Eric reported no amount of swapping chips and boards changed the fact that Y was not working but simply running the stepper test fixed it. That points to s/w to me and unless the PICs store anything across power off it looks like a problem at the host end.by nophead - RepRap Host
Perhaps the serial port was in the wrong mode, i.e not raw, and a character in the Y message had some special significance. Running the exerciser fixed it by putting the serial port in the right mode. If you are interested in solving the mystery you could try rebooting the PC and then doing the poke test again. As you might guess I don't like mysteries, in my experience if you ignore them and mby nophead - RepRap Host
They should be linked. I.e, run two wires between the three boards linking all the pin 1s together and all the pin 2s together. The signal is used to synchronise the stepping of the steppers so that you can move diagonally.by nophead - Controllers
You could load the Z code into the spare chip to rule out the chip being damaged. If it works in the Z position it looks like the Y firmware that is faulty. Also might be worth removing the other nodes from the ring as the reply has to pass through them so could get corrupted on the way.by nophead - RepRap Host
The other parameter to consider is the ripple current rating. That tends to be higher on larger caps, i.e. higher voltage ones. Sometimes a higher voltage part is specified to get a higher current rating. It does look like both parts are somewhat overrated. I must admit that when I design something at home, i.e. a one off I just pick parts that are generously rated and don't bother with the sumsby nophead - Controllers
This is in reply to Jonathan's question in the developer forum. Capacitor temperature and voltage ratings are not just the maximum the capacitor can handle, they also define its lifetime. Usually they are rated for 2000 hours at max current and voltage. In most application you want them to last longer so you derate them according to the formulas here . Lifetime doubles for each 10C drop in tempby nophead - Controllers
I don't think patents matter if your not doing anything commercial do they?by nophead - General
Rather than filling the bath you could rotate the object on a horizontal axis. That would get both halves, pretty much the same as the laser and turntable method but you have replaced the laser with milk and the turntable with a spit.by nophead - 3D Scanners, Book Scanners, and Optics
I recently managed to output 80 8 bit PWM signals at 1KHz using only one timer and some software in C. Who needs hardware PWM? Mind you it was on an 18 series running at 40MHz.by nophead - RepRap Host
Here is a relatively cheap way of stepping up voltages for PIC VPP.by nophead - Controllers
Yes you can also use the bulbs to light your machine for photography . You can add a fair amount of current to the low voltage rails without wasting masses of power because the voltage is low. It's worth trying if your 12V rail is too low or you 5V too high or in fact some PSU don't run with no load. They repeatedly start, go over voltage and shutdown again.by nophead - Controllers
You might want to consider moving to the 18 series, they have a much better instruction set for running C, although you need a compiler that makes use of it of course.by nophead - RepRap Host
Yes see my post in PowerComms + Programmer. PC PSUs are designed to run with massive loads on the 5V and 3.3V rails. When you use the 12V rail only they struggle to regulate. Adding a big dummy load to the 5V rail will probably bring it down into spec and raise the 12V rail as well.by nophead - Controllers
The trouble with using PC power supplies is that the rails are not individually regulated much. This means for example that if the 5V rail is very lightly loaded the whole PSU throttles back to keep it in range and the 12V rail tends to be too low. You can usually get the 12V rail to pull in spec by adding a big power resistor accross the 5V rail to give it a significant load. Not sure where theby nophead - Controllers
The 5V rail should be resonably clean when it leaves the PSU, appart from some high frequency switching noise, but after it has travelled around the machine next to wires carrying stepper motor currents and DC motor currents I would not use it to feed digital logic. You might get away with it but its not good practice. Also you would need to fuse it. PC supplies can give of the order of 20A on thby nophead - Controllers