EZ-B Connection Disconnection Issue

Thanks - that log line is expected. Below I explain why it appears, why your 2-5 hour disconnects most commonly happen when using a USBTTL cable, and give a stepbystep checklist and tests to isolate and fix the issue.

Why the log says "Reports EZB v4 OS With Comm 1"

• When you connect the EZB v4 over a USB TTL (UART) cable you are bypassing the EZB’s WiFi/Comm2 interface and using the hardware UART (Comm1).
• The EZB will therefore identify itself as "Comm 1" (v4.x/1) in the ARC log. This is documented in the EZB v4 manual: https://synthiam.com/Support/Hardware/EZ-B-v4

Why frequent disconnects (every 2-5 hours) commonly happen with USBTTL / UART connections

• UART/TTL over long or unshielded wiring is very sensitive to EMI/noise from motors, switching power supplies, WiFi, etc. This frequently causes intermittent corruption and disconnects.
• USBTTL adapter stability (chip type/driver) can be an issue (FTDI, CH340, CP2102 differences).
• Cable length, untwisted/unshielded wires, or floating unused wires can act as antennas and cause intermittent failures.
• Poor grounding or missing common ground between PC and robot.
• USB power issues (poor USB port, hub, or power saving/suspend).
• Wrong UART timing/baud mismatch or driver quirks (256000 is nonstandard for some adapters).
• Computer sleep/power management or automatic USB power saving can drop COM ports.

Immediate checks & quick tests (stepbystep)

1. Confirm basics

   • Which OS and ARC version? (Windows 10/11? ARC build?)
   • Which USBTTL adapter chip are you using (FTDI, CH340, CP2102)?
   • Cable length and wiring: how long is the cable between EZB and adapter? Are wires single jumper ribbon or shielded/twisted?
   • Are motors or highcurrent devices running while connected?

2. Try a knowngood short connection

   • Use the shortest, shielded cable possible (ideally < 12 inches / 30 cm).
   • Use a different USB port on the PC (avoid unpowered hubs). Try a different USB cable and/or adapter.
   • If possible, connect the EZB via its native USB port (not a long TTL jumper). This avoids UART noise completely.

3. Check drivers & COM stability

   • Update the USBTTL driver for your adapter.
   • In Device Manager, watch the COM port while connected - does it disappear/reappear when it drops? That points to USB/driver problems.

4. Try changing baud / timing

   • 256000 shows in your log - some adapters/drivers are flaky at this rate. Test using a standard baud (115200 or 230400) if your hardware supports it. Adjust the COM baud in the Connection control CONFIG COM/USB Connection tab.

5. DTR / RTS settings

   • In ARC Connection control CONFIG COM/USB Connection, toggle DTR and RTS checkboxes (try both enabled and both disabled). Some adapters and controllers require or behave better with DTR/RTS set.

6. Grounding / wiring best practices

   • Use twisted pair: pair TX with GND, RX with GND.
   • If using shielded cable, connect shield to ground at ONE end (preferably EZB side).
   • Avoid running UART wiring near motors, motor drivers, battery leads. Cross at 90 if they must cross.

7. Power / Sleep settings

   • Disable USB selective suspend in Windows power options for the used USB Root Hub(s).
   • Ensure the PC does not go to sleep and that ARC remains running.

8. Run the Connection Diagnostic skill & capture logs

   • Add the Connection Diagnostic skill to your project and run the tests. Copy the diagnostic log (use the "Copy Log" button) and compare messages at disconnect times. Skill info: https://synthiam.com/Support/Skills/Communication/Connection-Diagnostic?id=16164

9. If you can, switch to WiFi connection

   • For long term stability, connect the EZB over WiFi (Client/AP) instead of USBTTL; WiFi avoids UART electrical/noise limitations. See EZB v4 docs: https://synthiam.com/Support/Hardware/EZ-B-v4

Quick ARC JavaScript snippet to monitor connection status

• Add a JavaScript script to poll the connection status and log when it disconnects or reconnects. Paste this into a project script to capture timestamps of disconnects:

// Poll EZB connection status every 30 seconds and print changes
var prev = controlCommand("Connection", "GetStatus", 0);
print("Initial connected:", prev);
while (true) {
  var s = controlCommand("Connection", "GetStatus", 0);
  if (s !== prev) {
    print("Connection changed at " + new Date().toLocaleString() + " connected=" + s);
    prev = s;
  }
  // check every 30 seconds
  sleep(30000);
}

Follow-up diagnostics I recommend you run and report back

• Which USBTTL adapter chip (FTDI / CH340 / CP2102)?
• Cable length, wiring type (ribbon, twisted, shielded)? Are motors running while connected?
• Does Device Manager show COM port disappearing when disconnect happens?
• Can you try a short shielded cable or direct USB and report if disconnects stop?
• Also run the small monitor script above and paste the timestamps when disconnect happens (or the Connection Diagnostic log).

Useful links

• EZB v4 manual: https://synthiam.com/Support/Hardware/EZ-B-v4
• Troubleshoot USB connections: https://synthiam.com/Support/troubleshooting/Troubleshoot-USB-Connections
• Connection Diagnostic skill: https://synthiam.com/Support/Skills/Communication/Connection-Diagnostic?id=16164

If you post the adapter type, cable details, OS, ARC version, and a short excerpt of the Connection Diagnostic / ARC log around a disconnect time I’ll suggest the next, most likely fix (driver/cable/baud change or switching to WiFi), and give exact ARC settings to try.