Test and Measurement Forum

The ADC-16 is connected with a RS-232 cable to a laptop through COM1. The PicoLog software has been sucessfully installed to the laptop as well. An input voltage of 1.25V is inputted into Channel 1 on the board. But an error message indicates that "ADC16 COM1 unit not opened". When we checked the status on "Convertor Details", an message says, " ADC16 driver version 2.4ADC16 Unit not found. Can you let us know if we are doing anything wrong, or how to resolve this error. Thank you!

Hi,

This is a communication error where the ADC16 and the PC are not talking to each other. Please check that you have done the following:

Ensure that you PC has been re-booted after installation of the software.

Ensure that the ADC16 is plugged into the serial port directly with the serial cable provided, do not use switching boxes or through port dongles.

Check that no other serial port devices have conflicting IRQs, ie internal modems and other PCI cards. This can be checked by going to the control panel and checking the system properties of all serial port devices.

Is the port used with any other devcies such as Palm Pilots, scanners, zip drives, etc - if so, ensure that their software has been disabled.

If you have done all this and the ADC16 still gives the same results then check the voltage being supplied to the ADC16. Connect the ADC16 to the PC's serial port with the cable. Start Picolog up and then unplug the serial cable from the ADC16. With a multimeter test the voltage.


Pin 5 - Gnd
Pin 7 - >7 volts (positive voltage)
Pin 4 - <-7 volts (negative voltage)

If the voltage that you are getting is not in this range then this two can stop communication.

The solution at this point would be to use a USB to serial port convertor.

Best regards,

Hi,

I am now using a usb to serial adapter and the same problem persists. I have checked the voltages across pins 7&5 and 4&5. The voltage across 7&5 is >+7V but the voltage across 4&5 is actually identical to the one across 7&5 and not negative, as it's expected. Is there anyway to know if the ADC-16 is actually working itself? The ADC-16 has previously been used in other projects, so is there anyway to detect if the device is actually defective?

Hi,

Check the ADC-16 on a different PC, does it still give you the same results.

When you checked the voltage you did connect the ADC-16 and then start Picolog, before testing the voltages.

Have you checked the conformity of the serial cable that you are using. It should be straight through.

If you have checked all this and the unit still will not work then we will need to get it back so that we can investigate its problem. To do this I will need your contact details, so that I can give you a returns number. Please email me these details to:

email: tech@picotech.com

Best regards,