If the channel in LabChart is set at the full ±10 Volt range and the Volume signal is still saturating, you may need to adjust the Gain in the MPVS Ultra Control Interface software. This issue may happen in only one or multiple Volume segment channels.
Signal saturation in LabChart may look something like the figure below:
How to Adjust Gain Settings in MPVS Ultra Control Interface
1) In the Millar Control Utility software, select the appropriate catheter in the Millar Catheter Selection section at the top of the window.
2) Next, click the orange box labeled Catheter Configuration Locked to unlock the catheter. The box should turn to green, with the text inside the green box changing to Catheter Configuration Unlocked. This will automatically relock after 60 seconds, but can easily be unlocked again. This allows configuration of the catheter, including setting the Gain, Zeroing, Calibration, and selecting active electrodes/segment preference. The values available in the Conductance Range box will depend on the catheter selected.
3)In the Conductance Range section, you can toggle between the Show Conductance Display option and the Show Volume Display option. If you know the approximate volume for the test subject, use the Show Volume Display option, and select the value that encompasses the total volume measured across all segments (composite volume, or total chamber volume). If it is unknown, use the Show Conductance Display option, and choose a value that encompasses the total conductance across all segments (composite value before calibration).
This effectively adjusts the Gain.
NOTE: These values will change the options available in the Catheter Calibration tab, as well (see below).
Please Note: The Gain settings in the MPVS Control Interface Software are inverted when compared to standard gain amplification nomenclature. For example, x1 gain is the highest gain level in the Control Interface Software instead of the correct nomenclature of x100 being used for the higher gain level. This is a known issue in the software and will be corrected in a future release.
For further technical assistance with this or any other issue, please contact ADInstruments Technical Support by clicking HERE.