101 – Transducer Calibration and Signal Re-Scaling

AcqKnowledge software allows users to rescale any analog signal being acquired. Instead of simply measuring voltage, input signals can be scaled and renamed to more meaningful units. The rescaling function can also be used to calibrate a force transducer or similar device so that the recorded data matches the physical measurement of the transducer—the only requirement is that the data being acquired is an analog signal. Analog channels are the most common type of acquired channel and should be used to acquire any data with continuous values. The range of input values for analog channels using the MP150 is ±10 Volts.

There are various applications and uses for calibrating and rescaling different signals. A general knowledge of the three applications listed below will help address and hopefully solve any problems you might run into.

• skin temperature measurement using SKT100C
• displacement transducer calibration using SS14L with TCI114

• accurate signal measurement (reversing the amplified gain setting)

Note: The calibration and signal rescaling procedures detailed in this application note are intended for AcqKnowledge 4.0 and earlier; for AcqKnowledge 4.1 and higher, it’s recommended to use the MP150 > Set Up Channels > Add New Module feature, which automatically scales the signal based on the selected transducer or hardware. If additional scaling modifications are desired, they may be manually applied via the “View by Channels > Setup” option.

Associated Applications

• Psychophysiology - Record and analyze BP, ECG, HRV, EDA, EMG, EEG, EOG, RSP, etc. Interface to stimulus presentation programs...use automated analysis routines to easily score and analyze data.
• Sleep Studies - Long term recordings with up to 16 channels of data. Record EEG, EOG, EMG, respiration, temp., sound, limb position and more. Filter out EEG frequencies to score sleep stages.
• Noninvasive Blood Pressure Monitoring - Human - Human—continuous system with finger sensor. Fits children through large adults. MRI system also available.
• In vitro Pharmacology - Record from tissue bath, isolated organ, Ussing chamber, or use field stimulation. Advanced algorithms analyze Langendorff, working heart, and isolated perfused lung data.
• Laser Doppler Flow - Record microvascular circulation invasively or noninvasively with LDF100C. Look at the effects of drugs, exercise, inadequate blood supply, and tissue ischemia.
• MER: Micro-electrode Recording - Use micro-electrodes and MCE100C amplifier to record in-vivo or in-vitro from organisms, organs, tissues, brain slices, and cells. Record from up to 16 amplifiers simultaneously.
• Respiration | Pulmonary Function - Perform lung volume measurements, examine pressure/volume relationships, and analyze respiratory gases. Use AcqKnowledge to integrate airflow and analyze data.
• Exercise Physiology - Examine ventilation, oxygen uptake, carbon dioxide production, biopotentials, temp., and biomechanical signals simultaneously. Record wirelessly with BioNomadix.
• Biomechanics - Use BIOPAC equipment for gait analysis, goniometry, ergonomics evaluation, range of motion, EMG, Remote Monitoring or to interface with third-party equipment.
• Remote Monitoring - BioNomadix modules provide high quality, full-bandwidth data for a variety of signals—ECG, EEG, EGG, EMG, EOG, PPG, RSP, SKT, Accelerometry, Cardiac Output, Dynamometry, and Heel-Toe Strike.
• Amplifiers & Interfaces - Use BIOPAC amplifiers with MP Systems, as stand-alone devices, or with 3rd-party flow meters, force plates, sono-micrometers, telemetry equipment, metabolic carts, etc.