#31
|
|||
|
|||
Quote:
Now that's one less to worry about for me. Last edited by Nikonauts; Wed 07 January 2009 at 04:11.. |
#32
|
|||
|
|||
My G540 arrived yesterday and I had time today to start running it through its paces. I started out with some PK268-02AA motors (because I have a drawer full of them and I wouldn't be too upset if I fried one). However, I was pleasantly surprised. The G540 handled the 2A motors at 48V without any problems. When I get time, I'll hook up some PK296B2A-SG3.6 motors and see what happens.
I'm still concerned with the DB-9 motor connectors. In a perfect world, they would handle the current, but . . . It looks to me, that if you screwed the DB-9 connectors firmly in place and didn't make habit of removing the connectors, that the G540 would be a viable alternative to the G203v stepper drivers. The I/O on the G540 is limited with two outputs, four inputs (plus the disable input), and a VFD speed control built in, but that would be enough for most CNC routers. The unit is well built. I pulled the cover off to take a look inside and saw that Mariss had done a great job - as usual. After more testing, I'll be able to form a more accurate opinion, but on first look, the G540 is impressive. It certainly is simple to hook-up and because of its limitations, the control box could be much smaller than a box built for the G20x stepper drivers. |
#33
|
|||
|
|||
That DB9 connector also means that some soldering needs to be done. That is another potential can of worms, because it is not the easiest soldering for a beginner. It needs some practice and practicing on those connectors can get expensive. Maybe get some old/spare connectors to practice on first. The tip of the soldering iron should be shaped nearer to a blunt pencil, rather than a screwdriver.
The posts relating to the soldering of the connectors were moved to their own thread: http://www.mechmate.com/forums/showthread.php?t=1486 |
#34
|
|||
|
|||
BTW, there is a special for the 540 running at the cnczone, here are the details: http://www.cnczone.com/forums/showth...304#post560304
|
#35
|
|||
|
|||
The G540 drives four PK296B2A-SG3.6 motors very well.
I've got the test bench configured with a 35VDC power supply, four PK296B2A-SG3.6 motors, the G540 and cables with 3.2K resistors. The 1K + 2.2K resistor combination is the closest match I had on hand to 3K. The G540's current limit resistors require 1K per amp of motor current. The PK296B2A-SG3.6 steppers are rated at 3A, but the PK296-F4.5 is rated at 4.5A. All other electrical specs for those two motors are identical, so I'm assuming that Oriental Motor has de-rated the PK296B2A-SGxx motors because of the gearbox. In any case, I thought that driving the steppers as close as I could to the G540's 3.5A current limit would be a good exercise. For those who are wondering what the difference is between the PK296B2A-SGxx motor and the PK296A2A-SGxx motor, the PK296B2A-SGxx motor is the PK296A2A-SGxx motor with a dual-ended shaft. After an hour of running all four motors at speeds ranging from 50 RPM to 1300 RPM (motor shaft speed, the gear box's output shaft is turning 3.6X slower), the motors are at 90F and the G540 is 100F. The G540 is just sitting on a wooden bench without heat-sinking of any kind. Wiring time, compared to connecting the PMDX-122 and four G20x stepper drives is minimal. It took just over 1/2-hour to build four new cables this morning, including the time it took to install shrink-tubing on the cables and the time it took to install ferrules on each wire. It looks to me like the G540 would be a good stepper driver for a MINIMAL system (assuming that the DB-9 connectors continue to carry the required Amps). Edited: My G540 is one of the "custom" units that Pablo referred to. I has a non-standard nut on the DB-9 female connectors to suit a particular customer's special needs. If I use this G540 in production, I will have to use a non-standard length screw and some spacers between the DB-9 female and DB-9 male connectors. Last edited by Richards; Sat 07 February 2009 at 10:25.. |
#36
|
|||
|
|||
G540- yes or no?
Hi all,
This my first post. Found out about this site last Monday and can’t stop reading!! Must Build MechMate!! I have done nothing all week, because I have been up every night till 5am! Thinking of using the g540 on my MM for 3 reasons 1) It’s almost $400 cheaper (vs. 4-203v's and bob) 2) I am in CA with Gecko (so shipping is cheap if it has to be sent back a couple of times) 3) It’s almost $400 cheaper, I could buy 2 and still be ahead I am planning on building MM with the PK299A2A7.2 as per recommended, anyone foresee any other reason for not using the g540? as yet, other than the DB9 connectors. Also had a thought on the DB9 could you buy 2-DB9 patch cords cut them in half Splice in shielded cables and resistors inside you’re your control box? Much easier to splice than solder ends, I think. Thanks Gerald and all for this grate site and all your hard work. I don’t think I can sleep till I finish this thing The posts relating to the soldering of the connectors were moved to their own thread: http://www.mechmate.com/forums/showthread.php?t=1486 |
#37
|
|||
|
|||
Gerald,
Thanks for the pics I understand what a DB9 connector is and as far as soldering goes it is a easy job, but will not be as durable as the factory molded connectors. Just not sure about the gauge of the simple DB9 patch cord. I can’t believe I must have had 10 of them around and threw them all out. Anyway my g540 will be here tomorrow. |
#38
|
|||
|
|||
I have sold over 30 of the G540's systems. I too was worried about the DB9 connectors. I talked with Mariss about that . He stated that the db9 were easily rated for the currrent that the G540's put out. In my own tests I have not had a problem with the connectors. I have run into problems with some chines 10ft cables getting hot. With 22 AWG cable there isn't a problem.
I have a crimping tool so I buy the db9 crimp type pins for uses with the connectors. The regular low cost crimping tools that they sell for that job doesn't do a good job. I have a expensive tool that does a great job. I bought it on ebay for a fraction of the cost. Dan Mauch Advertising section of this post moved here. |
#39
|
|||
|
|||
G540 and prox,s
Mike,
You mentioned early in this thread The G540 can be used with the two wire prox switches. Can they be used in series? I have done some looking around but have not come across a circuit diagram for the G540 any body have a line on one. MAC |
#40
|
|||
|
|||
#41
|
|||
|
|||
G540
Thank you for your reply. I do have the manual. It shows limit switches each
with it's own Pin. Can they be wired in series to one pin leaving more in put free? The diagram I was wondering about, for the BOB in side. Thanks MAC |
#42
|
|||
|
|||
Mac,
The G540 inputs are not form c (dry contacts) thus, I would suggest you need to add a simple relay to the prox sensor and wire those in series. I have a detailed explanation of this in the following threads: http://www.mechmate.com/forums/showt...ht=prox&page=4 Certain Proximity sensors will allow you to wire in series, but I found that a certain small level of BAD EMF is picked up by the proximity sensor and the addition of relay's on all my machines elimitated/isolated that. The relays I used are the DIN mounted and located in this thread http://www.mechmate.com/forums/showt...t=prox&page=10 |
#43
|
|||
|
|||
Proximity sensors Relay
I feel this is the best way also, question was over an early post.
I think I m on the right track using relay in series MAC |
|
|