Set-up Serial Communications

Connecting to the BMS controller RS232 serial port with a computer COM port.

A terminal can be connected to the RS232 port on the BMS controller to program and monitor it.

While pretty much any terminal will work, typically a computer running a terminal emulation program is used.

• PC computers
  • For PC computers with a serial port, use a DE9 extension cord (male DE9 to the controller, female DE9 to the computer) and connect it to any COM
  • For PC computers without a serial port, use a RS232-USB dongle
• Apple MAC computers
  • For Mac computers with a printer/modem port, use a male DE9 to printer/modem port cable with a null-modem and connect it to the Modem port or the Printer port.
  • For Mac computers without a printer/modem port, use a RS232-USB dongle

To communicate with the BMS controller, a serial port is needed (a male DE-9* connector: 9 male pins surrounded by a trapezoidal metal shroud) Few laptop computers have serial ports any more. If your computer doesn't have a serial port, you'll need a USB-Serial adapter (dongle).

* Yes, DE-9 (not DB-9): DA-15, DB-25, DC-37, DD-50, DE-9

• Windows:
  • Connect the dongle to a USB port
  • When asked, insert the CD that came with the dongle into the CD drive
  • When done, take out the CD
  • Open a terminal emulation application (see below)
• MAC OS-X:
  • Insert the CD that came with the dongle into the CD drive
  • Navigate to the installer package (e.g.: Driver/(USB-SERIEL2302)/mac/md_pl2303hx_v108b3/PL2303_1.0.8b4.pkg)
  • Open the installer package and follow the instructions (select your hard drive when asked)
  • When done, eject the CD
  • Open a terminal emulation application (see below)

• 19200 baud
• 8 data bits
• no parity
• 1 stop bit
• Flow control: none

• Pin 2 = TXD: from controller to terminal
• Pin 3 = RXD: from terminal to controller
• Pin 5 = GND

No other pins are used.

To communicate with the serial port, you will need a terminal emulation application.
Unlike previous versions of Windows, Vista doesn't have HyperTerminal.
Many options are available; most are quite poor (HyperTerminal), or way too complicated and unfriendly (Indigo Terminal). Few are free.
Our recommendation is a very simple yet powerful, free application that has been the workhorse of computer geeks for a long time: PuTTY.
Here are the instructions to set-up PuTTY to talk to the BMS controller.

• Download PuTTY.exe from PuTTY download page
• No installation is needed
• Open PuTTY; a window will open
• In "Connection type:" click "Serial" (left-most radio button)
• In "Serial line" enter the COM port used (such as "COM7")
• In "Speed" enter "19200"
• Click "Open" or press the Enter key on your keyboard; a new window will open, replacing the old one
• To get to the Home menu, press the ESC key on your keyboard, or cycle the power on the BMS controller Off and on

• For Windows computers up to XP, use HyperTerminal (Start / Accessories / Communications / HyperTerminal)
• HyperTerminal will ask you for a modem type (ignore it), and may require you to press control-C before it will operate.

• Download ZTerm (free)
• Open the "ZTerm 1.1...OSX.dmg" file to extract it; a new disk image window opens
• Drag the contents of the disk image into the "Utilities" folder in the "Applications" folder
• Open the "Zterm" application; a window opens
• Unselect "Edit/Save Lines Off Top..."
• Select "Settings/Connection..."; a dialog opens
  • Set the "Data rate" to 19200; click "OK"
• Select "Settings/Modem Preferences..."; a dialog opens
  • Select the "Serial Port" to the port with the USB-Serial dongle (e.g.:"usbserial0"); click "OK"
• To get to the Home menu, press the ESC key on your keyboard, or cycle the power on the BMS controller Off and on

Kermit and minicom
Sample .kermrc file
rothen@ublt:~$ cat .kermrc
set line /dev/ttyUSB0
set speed 19200
set carrier-watch off
set flow-control none
c

We don't know what that means, but that's all we could get out of a Linux user. If you can translate that into English for us humans, please let us know.

In a PC computer, the terminal emulation application will ask you for the COM port. For computers with a serial port, that is usually COM 1. On the other side, if you're using a USB-RS232 adapter (dongle) the COM port will vary, and will depend on which USB socket you're using. There are 2 ways to find out which COM port the dongle is using.

1. Trial and error
   • Try COM1. In that doesn't work, try COM2; etc.
2. Look it up
   • Click the "Start" icon on the bottom right; the Windows menu pops-up
   • In the "Start Search" field at the bottom type "Device Manager"; "Device Manager" appears at the top of the list
   • Click the "Device Manager" item; a dialog appears: "Windows needs your permission to continue"
   • Click "Continue"; the "Device Manager" window appears
   • In the list, find the "Ports (COM & LTP)" item
   • Click on the '+' sign to the left of it; the item opens, showing the ports that are used
   • Note the number of the COM port (if you later use a differ USB port, the COM number will change!)

Troubleshooting guide