Configuring USB-MaxSonar® Ultrasonic Sensors

Multiple Sensor Operation

1. Open a second terminal window 2. Click settings 3. Change port to match the newest COM# 4. Configure the COM port settings to the required values in the chart on the top of this page 5. Click ok

1. Download terminal program 2. If the operating system doesn't recognize the sensor, drivers are available to download here 3. Configure terminal program 3. Select "Settings" menu 4. Select "Modem Preferences" option 5. Select "usbserial0" the zero may change depending on hardware configuration 6. Set the following options a. Set "Data Rate" to 57600 b. Set "Data Bits" to 8 c. Set "Parity" to None or 0 d. set "Stop Bits" to 1 7.Remove check boxes from "Flow Control" options 8. The "Service Name" can be named at the user's preference 9. "Phone Number", "Pre-dial init", and "Password" options can be left blank Please be aware that we have not evaluated Zterm for operation with the USB‑MaxSonar ultrasonic sensors. If you have a preferred terminal software, it can be configured with the same settings of Zterm

Computer USB ports have latency and buffer sizes which can change the time between the range readings reported by the USB‑MaxSonar ultrasonic sensors. This time delay can be caused by the USB hardware on the computer’s system board, the chipset managing USB communication ports, the age of the computer hardware, the number of devices using USB communication, and by the computers operating system. When multiple USB connections are working in parallel, such as a mouse, keyboard, and flash-drive, the bandwidth is shared among the devices. When bandwidth is shared between devices, the buffer and latency is increased due to the extra demand of resources from the computer chipset. The following direction sets are how to help lower the latency of the USB port in the computer's operating system.

Windows Users

For advanced Windows users, this instruction set will allow the use of a low-latency mode of operation for the USB‑MaxSonar. 1. Open "Device Manager" 2. Expand the "Ports (COM & LPT)" menu 3. Select the COM port that is assigned to the USB‑MaxSonar 4. Right click on the COM port and go down to "Properties" on the new menu 5. On the Communications Port Properties window select the "Port Settings" Tab 6. Click on the option that says "Advanced" 7. Set the "Recieve (Bytes)" option to 512 8. Set the "Transmit (Bytes)" option to 512 9. Set the "Latency Timer (msec)" option to 2 10. The "Serial Enumerator" option should be checked. This setting makes Windows remember the COM port assigned to the Device When this is unchecked, Windows will assign it the first available Com Port A screenshot of what the Advanced Communications Port Properties window should look like after configuration can be seen here.

Linux Users

For advanced Linux users that wish to operate in low-latency with the USB‑MaxSonar please use the following directions. While operating in low-latency mode, the USB buffer delay will be reduced to 128mS at most. 1. Open xTerm window 2. Type the following command: $ dmesg | grep FTDI. a line that looks like "/dev/ttyUSB#" will be output 3. enter the following command. $ setserial /dev/ttyUSB# -g. The # sign will be the USB port assigned to the USB‑ProxSonar‑EZ sensor. Information will be output that looks like"/dev/ttyUSB#, UART: unk, PORT:0X0000, IRQ:0". 4. Enter the low latency command: $ setserial /dev/ttyUSB# low_latency. This command will set the USB‑MaxSonar into low-latency mode. It is recommended that the configuration is confirmed. 5. Enter the command $ setserial /dev/ttyUSB# -g. The low-latency flag should be appended as follows: "/dev/ttyUSB#, UART: unk, PORT: 0X0000, IRQ: 0, Flags: low_latency".