IOU06 Quick-Start-Guide / Serial Demo

Serial Port Demo

In this demo, we’ll demonstrate how to connect an application on ModuCop with a IOU06 COM port. We’ll use a cable to loop the RS422/485 transmit pins to the receive pins, so that we’ll get all characters back that are sent to the COM port.

Preparation Steps:

  • Connect a PC and ModuCopto the same network, e.g. by using an Ethernet Switch or a Wifi Access Point
  • From the PC, login into the ModuCop via ssh

Check whether IOU06 COM ports are recognized on ModuCop

ModuCop’s linux image is configured to detected COM Ports of io4edge devices automatically.

For each detected COM port, a linux device /dev/tty<device-ID>-com is created. For example, if your IOU06 device ID is S101-IOU06-USB-EXT-1, you’ll find the following tty device:

root@moducop-cpu01: ~# ls -l /dev/ttyS101-IOU06-USB-EXT-1*
crw-rw---- 1 root dialout 199, 3 Jul 28 13:33 /dev/ttyS101-IOU06-USB-EXT-1-com

If you don’t see this device, but you see a -can device, you have to clear the CAN configuration, in order to activate the COM port.

On your ModuCop, run:

io4edge-cli -d S101-IOU06-USB-EXT-1 set-parameter can-config ""
# Restart to apply parameters
io4edge-cli -d S101-IOU06-USB-EXT-1 restart

Function Test

Now, let’s make a hardware loop between the RS422/485 transmit pins to the receive pins of the COM1 RS232 interface. Connect pin 1 to 4 and 6 to 9 of the CAN/COM port D-Sub connector:

Rev. 0

COM Loop

Rev. 1

COM Loop

Start the minicom terminal program on ModuCop:

root@moducop-cpu01: ~# minicom -D /dev/ttyS101-IOU06-USB-EXT-1-com1 -b 115200

Because we don’t have hardware flow control lines, we have to tell minicom not to use hardware flow control:

  • Press CTRL-A followed by O (O like Omega)
              │ Filenames and paths      │
              │ File transfer protocols  │
              │ Serial port setup        │
              │ Modem and dialing        │
              │ Screen and keyboard      │
              │ Save setup as dfl        │
              │ Save setup as..          │
              │ Exit                     │
  • Select Serial Port Setup
  • Press F

Then hardware flow control should be off:

F - Hardware Flow Control : No

Press two times ESC and you are back in the main screen of minicom.

Now type some character, and you should see that the characters are echoed back, due to the hardware loop we have created!

Welcome to minicom 2.7.1

Compiled on Apr 18 2017, 09:55:23.
Port /dev/ttyS101-IOU06-USB-EXT-1-com, 13:45:27

Press CTRL-A Z for help on special keys


To leave minicom, type CTRL-A, followed by x.