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My Experiment Stops Collecting Data in the Middle

"My Experiment starts, but hangs in the middle of data acquisition."

Possible Cause: Interrupt Overrun

An interrupt is a signal generated by a hardware device such as a potentiostat which tells the computer that the device requires attention.  Gamry potentiostat generate interrupts whenever a data point has been acquired.  If the computer cannot read that data from the potentiostat before the next data point is taken, an “Interrupt Overrun” error occurs.

Steps that may help solve the problem:

1.  Turn off display hardware acceleration from the Windows Control Panel:

  • Windows 98: Display -> Settings -> Advanced Properties -> Performance 
  • Windows 2000: Display -> Settings -> Advanced -> Troubleshooting
  • Windows XP: Display -> Settings -> Advanced -> Troubleshoot
Set the Hardware Acceleration slider to "None".

2.  Check that no other device is using the Gamry Potentiostat's IRQ:

Open the Device Manager from the Control Panel by selecting:
Windows XP: Performance and Maintenance -> System -> Hardware -> Device Manager

Highlight the computer icon at the top of the list and then click View/Resources by Type. Selecting IRQ will bring up a list of the possible interrupts and the device assigned to them.  The Gamry PC4 Potentiostat family can use IRQ values 5, 10, 11, and 15.  Interrupt 5 or 10 is preferred.  Make sure that no other device is assigned to the Gamry's IRQ.  The Gamry Potentiostat will not appear in this list.  If another device is using the desired interrupt, such as a sound card or network card, it must moved to another interrupt, or physically removed from the computer. 

Reserve the IRQ as a


3.  Reserve the IRQ as a "Legacy IRQ"

This requires changing the settings of your computer's Bios.  When your computer is booting up, a special key should allow you access to your computer's Bios settings.  The boot screen generally tells you which key. Often this is the Delete key (DEL) or the F2 Function key.  The Bios setup program varies quite a bit from computer to computer. 

4.  Turn off Power Management

Turn off all the Power Management features so that all portions of your computer stay powered up at all times.  From the Control Panel select Power Options/Power Schemes.  Select:

  • Power Scheme: "Always On"
  • Turn off Hard Disks: "Never"
  • System Standby: "Never"

It's OK to turn the monitor off after a time.  That does not interfere with running experiments.  It just keeps you from seeing the results! On some older computers you may have to re-boot your computer and enter the BIOS setup program (observe monitor during power-up to determine Hot Key).  Go to the Power Management Section and disable all power management features so that all peripherals stay ON while the computer is ON.

5.  Disable the Screen Saver.

They can tie the processor up needlessly.

6.  Disable any Anti-Virus applications.

If this works, try adjusting the application’s settings to allow for manual scanning only.

7.  Remove the Network card and its driver.

Network Interface Cards and their supporting drivers may also play a part in inducing interrupt overruns. You should remove the NIC driver completely to see if it is causing the problem. Heterogeneous networks with more than two protocol stacks are notoriously balky. Also try getting the latest NIC drivers from your vendor.

8.  Remove unneeded background applications

Often there are background utilities that are running while the Gamry Framework is running. 

Use Ctrl-Alt-Delete to bring up a task list.  OSA.EXE and FINDFAST.EXE often interfere with interrupts.  These are installed as part of the Microsoft Office Standard Installation and automatically start when Windows finishes loading.  OSA.EXE is responsible for loading the Microsoft Office shortcut bar and helping various Microsoft applications load and initialize faster.  FINDFAST.EXE is a notoriously unstable program that indexes your office files on your fixed drives for full-text content searching. 

You should remove FINDFAST.EXE and OSA.EXE from your Start Up folder.  While you’re there, remove the Microsoft Office shortcut as well.