Mesa 5i20 daughter cards

Rick,

The 5i20 is all you need for EMC unless you need the extra plug on the 5i22. I used 7i37ta isolated I/O cards on my Hardinge conversion as all my I/O is 24vdc... you need to pay attention to that as some cards are only 12vdc and some are ttl only etc. just depends on what you need. On my plasma cutter I went direct from the 5i20 to my Gecko 203v drives but used 7i37 for I/O...

John

Rick G wrote:

Hello all,
We are just about done with the mechanical work of converting our newest knee mill to EMC.
It is now time to decide on electronics. Although the parallel port has been fine on the machines we have done in the past we are now looking for a smoother, higher step rate and more inputs.

The 7i43 is possibly worth a look too, it connects to the P-Port and gives you the fast hardware stepgens and encoder counters up to a total of 48 IO lines. It might make wiring easier in some situations. (It is what I use on my mill/lathe combo.) Functionally it is equivalent to the PCI cards, apart from having fewer IO lines (the PCI cards have 72 or 96 pins) and then there is the external PCIE 3x20 card with 144 pins. I don't know how well EMC2 works with the 3x20, but the driver certainly knows it exists.

You might not need any daughter cards at all, the various stepgen etc outputs are available as logic levels on the FPGA card connectors. The daughter cards are mainly various types of signal conditioning.
My 7i43 plugs in to a section of stripboard with pin headers on it for each line. Some are wired to buffer ICs to drive relays, but many of them wire straight to encoders and limit switches.

There are a range of different firmwares available for each Mesa card with various combinations of modules, but you get a choice of how many of each you initialize and any unused pins are available as general purpose IO. I am not sure whether unused pins are easily usable with daughter-cards fitted, but there is no reason you can't fit two output connectors to the ribbon cable and only have a subset of the lines crimped into each.

I made a little breakout board from a radio shack perf board and a plug from newark



John

PWM to voltage only needs a resistor and a capacitor in its simplest incarnation. You can probably do it by mounting the components on the VFD terminal clamps (not that I am actually advocating that)

My "Breakout" is effectively identical.
I mounted a ULN2008 to the board to drive the FWD/REV button contacts on the VFD
The PWM was a little more complex as I needed a fully isolated 0-10V for a speed controller where the reference was the +100V line....
I ended up with an isolated 5V-12V DC-DC converter and an opto-isolated PWM-Voltage converter.

I have a schematic somewhere, but it turns out that I messed up the design and the PWM-voltage conversion is badly non-linear unless the PWM frequency is around 300Hz. If you are happy with a 300Hz PWM then I can forward the schematic.

The header part number is HRP50H-ND and I got them from Digi-Key
A terminal block that has the same pin spacing is A98074-ND and A98336-ND
I got the board from radio shack and don't know the part number.

The 7i24TA card for $45 from Mesa might be worth the hassle of making something. I might not have made them if I knew about the 7i42TA before hand.

John