072-0300
Alphasense User Manual
OPC-N2 Optical Particle Counter
Issue 5
Alphasense Ltd Page 12 of 34
December 2015
Sensor Technology House, 300 Avenue West, Skyline 120, Great Notley. Essex.CM77 7AA. UK
Tel: +44 (0) 1376 556700 - Fax: +44 (0) 1376 335899
Email: [email protected] - Web: www.alphasense.com
1. If a SD card is found, the OPC will check for a USB connection. The OPC-N2 comes equipped
with a micro USB port.
2. If a USB connection is found the device will switch to “USB mode”. This makes the OPC-N2
behave like an external storage device (pen-drive) until the USB is disconnected.
3. If a USB connection is not found then it will check for the SPI master connection (SCLK). The
OPC will wait up to 60 seconds for an SPI connection to be established.
4. If an SPI connection is not found the OPC-N2 will switch to standalone “SD card mode”. When
in SD card mode the SPI is still active, if SPI command “SPIShutDownDAC” (0x03) is sent, the
OPC will close the current SD card log file and exit SD card mode.
Please note that if the unit has entered standalone mode before you have connected the
software the following error will be returned:
Found USB-ISS Version 6
USBISS SerialNo = XXXXXXXX
Device interface = USBISS
InfoStr not Found
SPI Busy
This can be cleared by connecting a second time or if this fails unplugging and replugging in the unit
More firmware commands (via software)
There are four commands that can be used to edit factory settings through the OPC software:
1. Ctrl + R: Read and display all configuration variables. This will display the variables available to
the user for edit. The data is displayed in the information window to the right of the software
window.
2. Ctrl + W: Write all values to configuration memory. This command will write the current
configuration values to volatile memory, this means that the user can run the OPC with their
desired configuration but the changes will be reset once the power is disconnected.
3. Ctrl + S: Save all values to configuration memory. This command will write the current
configuration values to non-volatile memory, this means that the user can permanently save
their configuration values.
4. Ctrl + B: Enter Bootloader mode. This allows the OPC to interact with the Bootloader application
so that new firmware can be installed via USB port.
5. These commands are also needed to make full use of the stand alone mode
