Roller485 with PWRCAN and CORE

iorex

Hello,
I am trying to get a Roller485 to work with a POWRCAN module attached to a CORE controller but I don't seem to get it to run.
Please note that it does work over I2C.
Here's the configuration:

POWERCAN:
12V, line A to line A, line B to line B, TX:G17, RX:G16, terminator enabled.
Roller485:
RS485, node #:1, 115200 Baud, MODE: Speed

I am attaching the UIFlow2 application.
Thank you for your support.

import os, sys, io
import M5
from M5 import *
from module import PwrCANModuleRS485
from unit import Roller485Unit



label0 = None
pwrcan_0 = None
roller485_0 = None


def setup():
  global label0, pwrcan_0, roller485_0

  M5.begin()
  Widgets.setRotation(1)
  Widgets.fillScreen(0x222222)
  label0 = Widgets.Label("label0", 38, 38, 1.0, 0xffffff, 0x222222, Widgets.FONTS.DejaVu18)

  pwrcan_0 = PwrCANModuleRS485(2, baudrate=115200, bits=8, parity=None, stop=1, tx=17, rx=16)
  roller485_0 = Roller485Unit(pwrcan_0, address=1, mode=Roller485Unit.RS485_MODE)


def loop():
  global label0, pwrcan_0, roller485_0
  label0.setText(str('Label'))
  roller485_0.set_motor_mode(1)
  roller485_0.set_motor_speed(100)
  roller485_0.set_speed_max_current(100)


if __name__ == '__main__':
  try:
    setup()
    while True:
      loop()
  except (Exception, KeyboardInterrupt) as e:
    try:
      from utility import print_error_msg
      print_error_msg(e)
    except ImportError:
      print("please update to latest firmware")

iorex

I also tried the example app at:
https://uiflow-micropython.readthedocs.io/en/develop/units/roller485.html
(see roller485_485_fire_example.m5f2 : https://uiflow2.m5stack.com/?example=https://raw.githubusercontent.com/m5stack/uiflow-micropython/develop/examples/unit/roller485/roller485_485_fire_example.m5f2)

but it errors out:

E (10676) i2c: i2c driver install error
Traceback (most recent call last):
File "<stdin>", line 67, in <module>
File "<stdin>", line 43, in setup
File "unit/roller485.py", line 127, in get_motor_mode
TypeError: 'NoneType' object isn't subscriptable

It appears that the i2c error is benign.

Your help is appreciated.
Iorex

hammurabi

@iorex I’ve had partial success using the Roller485 with the pwrCan module. Your setup looks similar to mine, except I’m using a Core3, so my pin numbers are different.

First, check whether your motor is in RS485 mode. The screen on the back should show COM: 485.
Second, make sure the motor ID is set to 1. The third line on the motor screen should read ID: 0x01.
Lastly, confirm that the motor’s baud rate is 115200 (this is the default).

If all of the above is correct, you can move on to the pwrCan module. Did you flip the resistor for RS485 to the ON position? Are the DIP switches configured correctly?

I was able to control motor speed over RS485, but I still get the error: “Unexpected response length: 32, expected: 17.” It looks like there’s a communication issue from the motor back to the pwrCan module.

As an alternative, you can power the motor using the power pins on the RS485 terminal and send commands via I²C. It requires more wiring, but it works with much less hassle.