Newbie- IM483H/IM805H Drives and PSU

[stangtjk]

I'm planning on building a cnc router and I'm in the process of gathering up some electronics to play around with. I know the gecko G540 is highly recommended and I may eventually go that route but for now I'm just trying to put together a cheap system to learn on. I like the IM483H/IM805H plus drives because they seem to have a lot of features, are compact, and I found some on ebay for relatively cheap. I ended up winning two "best offer" auctions so now I have 7 drives on the way to play with (3 IM805H and 4 IM483H).

I've been looking over the data sheets for the drives and they don't seem to terribly difficult to hook up but the the 4 IM483H drives that I bought are already soldered to a pcb. I understand most of whats going on with the connections on the pcb from the data sheets but one thing has me a bit confused. The pcb is said to have its own DC power supply and can take either 115V or 230V AC as an input via a switch. I never cared much for EE so I'm not sure how well this setup will work. I looks like the board has a bridge rectifier and some capacitors for the "DC power supply" but there is no transformer or anything. I'm clueless when it comes to building a power supply but it seems to me that there will be some sort of downfall for the way this thing is designed so my question is what is it?

Here is the link to the drivers quick reference and data sheets.
http://www.imshome.com/downloads/qui...5h_plus_qr.pdf
http://www.imshome.com/downloads/manuals/IMxH_Plus.pdf

And some images of the board.

[vger]

Ok..... by looking at the board traces, counting power connections, and knowing how such things work... The switch on the board it to control how the primary windings on an external transformer will be connected to the line voltage. Many power transformers have 2 primary windings. Connect the 2 windings in series for 220 volts and in parallel for 110 volts. The connector that has 3 pins would be connected to the secondary winding of the transformer. That 3 pin connector leads to the bridge rectifier. You will need a transformer, and it's secondary will to connect to the 3 pin connector, but you will not necessarily need to connect the primary(s) to the board unless you plan on switching input voltage back and forth from 110 to 220.

Since the drivers on that board are 48V max, you will want a transformer that has a secondary voltage of 24 or 28 volts RMS (34 or 40 volts peak) output to be safe.

The small circuit in the upper right of the first pic of the board it probably the +5 volt logic supply for the drivers.

Looks like a nice board though... To fully reverse engineer it you would probably have to remove the driver circuits and have it X-RAY'd to follow the multi layer traces.

Make sure you attach a sizable heat sink to the drivers and to the bridge rectifier to keep them from overheating.

Steve

[stangtjk]

Thanks Steve, that makes sense. I should be getting the board today so I'll be able to get a better look at it. Do you know where the best place would be to find a suitable transformer? I did a little bit of searching couldn't really find what I was looking for. Could I buy one of the cheap $40 power supplies off ebay and steal the transformer from it?

I was thinking the top circuit was for the logic as well, it looks like there is an input for vcc and gnd right above it. I'm not sure what that circuit does but I'm assuming I need a separate 5v dc supply for that connection, what do you think?

I'm considering just pulling the drives from the board and just wiring them each on its own board using the minimum connections as shown in the manual so I can see whats going on.

[vger]

I would leave the drives on the board as it is. Tracing the control inputs to the individual drives should be a piece of cake. Once you get the board you will probably be able to read the number on the IC that is in the little circuit in the upper right. Just google that number and you should be able to determin what that circuit does. It appears to be a small switch-mode power supply (black thing labeled 101 looks like an inductor) and it may take the main DC power on the board and regulate it down to the +5 logic voltage.

JP10 - JP13 look to be the motor control connections, step, direction, enable, and a fault output. Connecting your BOB to those points should be easy.

You may need an ohmeter to determin which motor output pins are which. The ribbon cable connector on the lower right appears to connect to the same points as JP10-JP13, or at least part of them. Probably step, dir, and enable, without the fault outputs there.

As for a transformer, you will may be able to find someting cheaper than $40. It will need to be capable of delivering at least the maximum current drawn by all your motors combined. I don't know what motors you plan on using but the individual phase output current is listed as 3 Amps. The actual output current is adjusted by the value of the resistor(s) connected to pins 1,2,& 3. Take a look at the manual pages 21-24. Looks like there are jumpers on the board to adjust the current ouputs and possibly the current reduction.

Steve

[stangtjk]

I got the board today. It looks like the circuit in the corner is indeed the 5v logic supply and pulls power from the main power supply.

I was reading up on how to build a power supply from a pdf file I found in another forum on here to determine what transformer I would need and how the on board components work with it. I don't have stepper motors yet. I bought 4 new parker os series stepper motors off ebay which I'm planning on listing right back. I was looking at so many different motors and got the specs mixed up and ended up getting something I didn't want.

The drives are rated at 3A RMS/4A Peak. On the guide I was looking at it said the transformer should be sized to supply the sum of the currents from the motors being used multiplied by 67%. If I use the max driver current instead I would need a transformer rated around 10A (4A*4drives*.67=10.72A). To calculate voltage it said to use the desired DC voltage/1.414. The max voltage of the driver is 48V so lets say I want 45V for safety I would need a transformer with a 32VAC secondary.

I found these two transformers on ebay which seem suitable.
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT

I think I'm ok up to this point. Now its time to size the filter capacitor which was given by the equation (C=80,000*I/V) so I would need a capacitor of around 27,000uf. This is where I may have a problem, the capacitors on the board are only 1500uf. Should these be replace with larger capacitors?

[vger]

The caps on the board are probably in parallel, and there are caps right next to the drivers. If all the caps on the board are parallel in the circuit and they are all 1500 uf, then 10 X 1500 = 15,000 uf. That value should be OK. Take a look at the voltage rating on the caps. Generally... caps in circuit are rated at almost double the operating voltage... 20 Volt circuit... 35 V caps would be normal.

Steve

[stangtjk]

I got some more toys to play with.

My IM805H drives finally arrived. They are each on their own pcb. I spent a few hours with the multimeter trying to determine what pins did what. I think I finally figured them out.


Now I just need to decide what parts I'm going to use and get a power supply.

The IM805H takes an input voltage between 12-75V and has a 7A peak output. The boards I have are already setup for 7A peak and the holding current when at rest is set to 2A. I'm not planning on running a 7A motor so if I use these drives I'll have to replace the resistor. What would be a good value for the holding current in relation to the peak current (i.e 50%-75%)?

I have 4 155 oz-in stepper motors rated at 4A peak and they have and the phase inductance is 4.2 mH. They are probably too small for what I have in mind but I couldn't pass up the deal ($50 for all four and they've never been used). The board I have with the IM483 drives is already set up for 4A peak so the motors should run ok on it.

I still need a parallel card. I noticed some are based off different chips, is there anything in particular I should look for?

[vger]

Are you talking about a parallel card for the computer? or Breakout board?

Again, take a look at the voltage rating on the electrolitic caps on the individual boards and go with a motor power supply with a DC output about half of the rated voltage on the caps.

On the board that has the bridge rectifier, you will want a transformer with an output that is about 1/3 the cap voltage rating. A 24V transformer will have a peak voltage of about 33 V and that is the voltage the caps will see.

Steve

[stangtjk]

I was referring to a parallel card for my computer.

The caps on all of the boards are 63V.

I'm just going to repeat what you said to make sure I'm understanding correctly.

For the boards with the IM805 drives I should use a power supply around half the rated voltage of the caps (63V caps so use ~30V PSU) and for the board with the IM483 drives I would need a transformer approximately 1/3 the rated voltage of the caps (again 63V so use ~21V transformer).

Would a 30V transformer be ok for the board with the rectifier? That would supply a peak voltage around 42V. The boards are only rated for 45V max, would this be pushing it?

[vger]

That might be pushing it just a bit... suppose your normal line voltage was 115 V and that gave you 30 V on the secondary of the transformer. That'd be 42.42 volts peak. Then there is a little power surge and your line voltage jumps up to 125 for a bit (not too unusual) and your secondary voltage increases proportionally... your peak jumps to 46 V. Better to be safe than sorry.

Just about any standard parallel board will work for you. Does the computer not have a printer port built in? If you add a second port it will go to the second printer port address which will have to be set up in your software.

Steve

[stangtjk]

Neither of the 2 computers I have are equipped with a parallel port. The computer I'm currently using only has usb and 1 fire wire port. Seems most newer computers have done away with parallel. I have an old computer in my parents garage with a parallel port that would probably suffice but I have a pet peeve about using slow computers.

[ee_t]

You can get a pcie or pci to parallel port adapter, or a smoothstepper, etc.