I have a pmdx 424 in my CNC mill and it seems I’ve received every possible error in Mach. Can’t trace down the cause, and most of the errors are sporadic and random. I don’t have a VFD for my mill, and the usb cable is routed in such a fashion that it is isolated from everything else in the case.

Computer:
Windows 10 64 bit, Intel i5-4590T 2.00GHz, 8Gb ram

The errors I constantly receive:
Motion underrun error – Constantly get these while jogging the machine, especially when edge finding. I understand this is probably computer hardware related? My computer meets the Mach4 recommended specs and I have nothing but Mach4 installed on the computer with power settings set to “performance”. This error is not a massive deal because I can just hit enable and continue. I never see this error while running Gcode.
PMDX DEVICE ERROR ‘SYSTEM ERROR(18): Packet timeout, communications lost’ – This error seems very random, however I see it the most while jogging the machine around.
PMDX: Could not disable the PMDX-SmartBOB-USB, error ‘Cannot communicated with device’ – This error almost always shows up when I encounter a tool change in my Gcode files, specifically it will error out on T# M6 line of Gcode. I have an M1 optional stop the line before all my tool changes.
Error(17) – I’ve also received this error a few times, mainly at very random times.

Things I’ve done:
-   Reinstalled mach4 and the pmdx plugin twice. The second time, I started a brand new ini file (copy of the pmdx template) and manually changed all my settings.
-   Uninstalled/reinstalled ST vcom drivers
-   Updated windows
-   Power down everything, remove USB cable, boot PMDX board, wait 15 seconds or longer, plug in USB cable
-   Tried a different USB cable

I'm in the process of changing all step/dir and limit/homing wires to shielded wires with shields connected to the case ground, however, I can't see this doing much since the usb cable runs nowhere near any signal wires. Additionally, it's probably worthy to note that all AC power in the case is located in one corner and the usb/low voltage signal wires are all located in the opposite corner in an attempt to isolate any frequency issues caused by AC power.

I’m starting to get a little frustrated as my mill is rendered unusable, so any advice/help is greatly appreciated.

Could be noise or W10 taking too long to allow a smooth flow of data, up the buffer size on the PMDX if that fails reduce it so it needs data more often.

Thanks for the advice, increased the buffer size for jog movements to 250 (150 default), and saw a decrease in the amount of "motion underrun" errors while jogging, however, they were not eliminated.

I rewired my entire case with shielded cable. Shields are grounded to the case at one end. I also added ferrite noise suppressors to the usb cable. This seemed to slightly improve things. I cut air for about 45 mins and didn't run into any issues (losing connection at tool changes didn't happen), however, I don't think I ran for long enough to confirm the issues during gcode execution were resolved.

I am now receiving PMDX DEVICE ERROR ‘SYSTEM ERROR(18): Packet timeout, communications lost’ and PMDX: Could not enable the PMDX-SmartBOB-USB, error 'Internal Device Error 110 (Device not configured)' while jogging the machine around. These errors usually (but not always) follow immediately after a motion underrun error.

don't have Ethernet option?
i use pokeys ,cant said never had noise issue but only on extension cards(pokies have porelay cards connect via net work)
but i use only Ethernet
 

PMDX does not support ethernet.

Might help. Go into windows power settings and turn off all power off features except monitor
set hdd to always on. Set usb port to always on. Or ethernet port. Never let sleep happen.
set monitor to power off after ten minutes. and any other power save features.
I do this on all my machines if windows shuts down this or that you can get hung in the time it takes to start up

Just wanted to update this thread. I spent months trying to troubleshoot the pmdx board, I ended up completely rewiring my control cabinet, trying a different computer, etc, sent Steve @ pmdx multiple emails with no response. I just couldn't get the errors in Mach 4 to go away no matter what I tried...

So I got fed up and bought a pokeys57cnc. Plugged it in through ethernet and away I went. Not a single error, has been running reliably for the last few weeks and everything works great. Still have no idea what's wrong with the pmdx :/

if you compare to all big cnc producer in europe even in the east
no one use usb as com device with controler
also pokeys(that i use ,and i almost not have any problem with them)that have 2 options ,recomened use Ethernet

Pokeys 57CNC does not work with Mach4 on USB.  Works great over ethernet.

We use a ESS from Warp 9 with a PMDX-126 breakout board.
No problems.
I am sure that your issues are related to the USB.
Hate to say it but get away from USB control.