Seeking PC recommendations

Zahnrad Kopf wrote:

Getting ready to do a retrofit, here, and looking for current recommendations for a PC to use.
Have settled on Mesa cards and will be using my iron and servos.

I have an Intel D510MO, but that has been superceded by the D525MO, which also works well.

I run my D510MO board from an 8GB DOM SSD. It's working well so far, and was very cheap. It also means that you can use a very small PSU.
The SSD is one of these, which plugs directly into an SATA port
www.kingspec.com/solid-state-disk-produc...ata2channel-mlcj.htm
I have been rather abusing it, doing several full EMC2 compiles every night for a year or more with no problems, so there is no write-endurance issue, and in normal CNC use it will nearly all be data reading, where the endurance is infinite.
www.mini-box.com/picoPSU-80
80W is probably overkill for a fanless, SSD system. Note that it doesn't fit the whole PSU slot, but that doesn't matter.
If you have settled on Mesa then the combination of 5i25 and 7i77 looks like it should suit your requirements well.
(It should be fully supported when 2.5 is released, but 2.5 is available as a package from the Buildbot already, and is widely used)

Zahnrad Kopf wrote:

Can you please explain the differences in these "set ups" (below) for me?

Originally, Peter (I've written him a few days back, but haven't heard back yet)
had given me a recommendation of a 5I20, a 7I48, and one or two 7I37COMs.
How does this differ from the 5I25/7I77 combo?

7i48 is 6 analogue output channels with encoder conditioning, and 7i37 is 16 outputs and 8x 5-24V inputs.
7i77 is 6 analogue output channels with encoder conditioning, with 16x 5-28V outputs and 32x 5-32V inputs

The difference is that the 5i20/7i37 setup uses one-wire-per signal on 3x50 pin connectors, whereas the 5i25/7i77 combination multiplexes the data into a serial format, and the interconnection is via a 25-way parallel-port type cable.

In pinout spec they are very similar. With a second 7i37 you get another set of IO. The Mesa web site says that you can attach a second Serial card direct to the 7i77, but I am not actually sure this is true. But you can connect a second 25-pin header to the 5i25 and add one or two more of the Serial cards.

Neither setup uses the parallel port. One configuration of the 5i25 is as a "Super Parport" with a conventional pinout but on-card step/pwm generation etc, but it is a low-profile PCI card. In the suggested configuration the pinout is not the same as the parport, the communication is largely through a serial protocol (I think that the encoder signals are wired directly back to the 5i25, however)
This might mean that the 5i20 is faster, but I don't think this will ever matter.

I am not sure why Peter din't suggest the 5i25/7i77. The likely reason is that at the time even he didn't have a 7i77 and also there was no EMC2 driver for the cards. The 5i20/7i48 is a very much more mature and proven combination.

There is some price difference, the 5i20 + 7i48 + 7i37COM is $377, the 7i77 is not on the price list yet, but the 5i25 is only $89 and I _think_ Pete said that the 7i77 was around $150.