[ericdwilso]

Sam,

I am looking to build a servo CNC gantry mill. Thinking of using the MESA card with EMC2 (EMC2 for sure)...
I read that you got your H-Bridge circuit to work... Mind sharing the design?

Eric

[samco]

Sorry - I overlooked this tread.
http://www.electronicsam.com/images/...vostart/schem/
http://www.electronicsam.com/images/...start/mess.JPG
http://www.electronicsam.com/images/...art/almost.JPG

lets call it revision .01 The componants where picked for their package size - not what was actually used.

Here is the short list.

FDH44N50 N - MOSFET transistors 500V / 44A for the power mosfets.
RURG5060 Ultra Fast Diodes 600V 50A for the free wheeling diodes
IR2111 for the half bridge driver.
MUR120RLGOSCT-ND DIODE ULTRA FAST 1A 200V AXIAL for the boot strap.
LM340T-15-ND 15volt regulator
TLP2530-ND PHOTOCOUPLER DUAL 6N135 8-DIP
.1uf caps and
iirc 10uf electrolytics.
The big cap is 1200uf I think at 350volts (I think)

Couple things
- when there isnt any pwm signal applied to the bridge - both lower mosfets are on. (braking)
- I had a lot of help from a emc developer that does high power circuits for his real job.
- there is no current limiting yet.
- you should find lower Rds mosfets.
- if your going to run higher than 100v you need higer voltage boot strap diodes.
- this cannot have 100% duty cycle pwm signal other wise the boots strap doesn't get charged.
- use at your own risk (of cource)
- great care was made to have a short power circuit loop - to help get rid of stray inductance.

sam

Sam,

I am looking to build a servo CNC gantry mill. Thinking of using the MESA card with EMC2 (EMC2 for sure)...
I read that you got your H-Bridge circuit to work... Mind sharing the design?

Eric

[samco]

Also - the mesa board right now does only pwm+dir and my bridge does pwm+pwm. (known as up/down) so you will need a few extra logic chips to turn the pwm+dir out of the mesa board to pwm+pwm.

I think at some point they will have an up/down option on the mesa board - I keep mentioning it anyways.

sam