KB130: How to: Use two PMD-1024 devices on the same computer


You need more inputs and outputs than a single PMD-1024 device has, so you want to connect two of these devices to the same computer for use with IOLink.

Note: Measurement Computing have changed the name of these devices to USB-1024. If you want to purchase a device, you will find it under USB-1024, not PMD.


Typically, only one PMD is connected to a computer at a time, so IOLink only recognizes the first device connected, but you can configure two PMD devices and IOLink so that both devices work on a single computer.

To callibrate PMD devices for use with IOLink:

  1. Install the PMD drivers, provided by Measurement Computing, onto the same computer which has IOLink installed.
  2. Connect both PMD devices to the computer.
  3. Click Start > Programs > Measurement Computing > InstaCal. The InstaCal dialog box appears. InstaCal detects the device and the Plug-and-Play Detection dialog box appears.
  4. Click OK. The PMD devices appear in the InstaCal devices list.
  5. The Board and serial number for the devices are shown in the window.
  6. Note the board numbers of both devices.

Next, connect an IO device to the PMD, then test the connections.

To test an IO device connection:

  1. From the Omnivex software directory, located in: C:\Program Files\Omnivex\IOLink 3, start IOTest.EXE.
  2. The Omnivex I/O Hardware Test (IOTest) application window appears.
  3. In Board #, select the number of the board be tested.
  4. Click Check for Hardware. The IOTest application window is populated with data from the PMD device.
  5. Click Initialize Hardware. Port A configures as input and port B configures as output.
  6. To test the inputs, close a switch on the IO device. The corresponding port in IOTest changes from Open to Closed, as shown on port 4 in the example below.
  7. To check the output connection, select the output port that the IO device is connected to. The IO device responds.
  8. In Board #, select the number of the other board.
  9. Repeat steps 4 though 7.

When adding an input source to IOLink, ensure that the board number corresponds to the PMD you to be used.