Hardware Setup

Hardware setup consists of making the physical connections of the chamber and computer to the apparatus. In addition, the hardware must be configured within the software in order to calibrate the apparatus and perform data collections.

Below is a close-up look at the Chamber connections.  Please take notice that the words "DSI" is right-side up.  This will ensure that the signals are not inverted.  

Below is a close-up of the ACQ connections.  Please note that specific placement of the connections to the port will be mapped in the channel mapping of the protocol file (Groups section of P3 Setup).  

Calibration

Hardware Connections

Before you initiate calibration, please ensure the following:

1.  The plethysmograph is empty (no animal).

2.  The plethysmograph is closed tightly and sealed with the Calibration Plug

3.  Perform all connections similar to the diagram shown in the Hardware Setup

4.  The TSI Flowmeter is connected in line between the Bias Flow generator or regulated lab air source and the luer fitting on the Calibration Plug.

5.  An applicable Protocol file has been created in the Ponemah software.

Flow/Volume Calibration

There is a two-step calibration procedure for the chamber flow signal. First take a measurement of the zero flow, then apply a constant flow and take another measurement.

In order to calibrate the chamber, all ports must be closed off so that the only air flow is through the pneumotach. The only other connection to the chamber is the constant flow.

NOTE: For the correct Volume calculation, the inspiration portion of the signal must go in the positive direction. If the inspiration has a negative deflection the user can use the Invert Flow attribute in the Analysis Attributes for the signal.

To calibrate the configuration, launch Ponemah and navigate to the Hardware menu | 7700 Amplifier Setup. 

Pressure Transducer

In the Universal XE | General tab

In the Universal XE | General tab

• Set the Mode to Transducer.
• Set the Low pass filter to 30Hz. 
• Leave the the rest of the settings at default values.

In the Universal XE | Calibrations tab

1. Set the Excitation to 5V.
2. Enter Low and High Units based on the actual flow values you will use for calibration.
   • These values should be entered in units of mL/sec.
     • Conversion from L/min to mL/sec: L/min * (1000/60) = mL/sec
   • The Low Unit should be 0; as this will take a measurement at no flow.  
   • The High Unit is typically based on the flow rate your bias flow can achieve.
     • Mice: 1 L/min = 16.67 mL/sec 
     • Rat: 2.5 L/min = 41.68 mL/sec
3. Calibrate the Pressure Transducer
   • With no flow being provided to the chamber, left-click the Low Cal cell associated with the Pressure Transducer channel.
   • Select the Measure button.
   • Apply the bias flow to the chamber and wait for the flow in the chamber to stabilize. Typically, a TSI Flow Meter is placed between the bias flow and chamber to obtain an accurate flow rate and know when the desired flow has been achieved; see the calibration hardware connection diagram above.  
   • Left-click the High Cal cell associated with the Pressure Transducer channel.
   • Select the Measure button.
4. The Value cell associated with the Pressure channel provides real-time, calibrated data from the transducer connected to the channel. It may be used to test the calibration by applying various flows through the chamber. 

An example of the Ponemah ACQ-7700 calibration dialog for the Universal XE General Tab is shown below.  *Note, the values listed above (-51.19, 273.14, -0.7937, 0.1391) are not realistic values and were captured using demo mode.

An example of the Ponemah ACQ-7700 calibration dialog for Universal XE Configuration Tab is shown below. *Note, the values listed above (-51.19, 273.14, -0.7937, 0.1391) are not realistic values and was captured using demo mode. 

Temp/Humidity Probe

In the Universal XE | General tab

1. Set the Mode to V.
2. Set the Low pass filter to 30Hz. 
3. Leave the the rest of the settings at default values.

In the Universal XE | Calibrations tab

• Set the Excitation to 7.5V.
• Low and high values for Temp/Humidity calibration are provided on the on the label of the sensor.
  Note: Temperature calibrations are standard for all modified temp/humidity probes, but the Humidity calibration values are specific to each probe. 
  
  
  • High and Low Units for the Temperature need to be converted to Kelvin before entering the values in Ponemah:
    • 0 degrees Celsius = 273.15Kelvin
    • 50 degrees Celsius= 323.15 Kelvin

Suggested Span Ranges:

• Temp: 273.15-323.15
• RH: 0-100