Introduction

BIOPAC equipment is used to measure physiological signals, such as ECG, skin conductance, etc. The data is normally recording with the BIOPAC AcqKnowledge software.

Availability, support and advice

A BIOPAC setup can be borrowed from SOLO through the Helpdesk. SOLO has various modules available. BIOPAC is supported by SOLO, for questions please contact labsupport@fsw.leidenuniv.nl.

Markers

To analyze physiological data obtained with Biopac, markers that signal the onset of certain events need to be sent from stimulus presentation pc to the Biopac device. See for more information on sending markers the pages Sending Markers in E-Prime and Sending Markers in OpenSesame and the Markers and Events page for more information on markers in general.

Setups

At FSW Leiden we work with BIOPAC MP150/160 setups. These setups are great for measuring physiology in the lab. The setup consists of an MP150 or MP160 unit, an STP100C module, an UIM100C and/or HLT100C module, and one or more physiological modules, such as ECG or EDA. Below, a description of some of the different modules is given. Note that this list is not exhaustive, but gives an overview of modules (commonly) used at FSW Leiden. See the BIOPAC website for more products.

Biopac basics

Modules

• MP150/160
  The MP150 or MP160 unit is the basis of a (lab) BIOPAC setup (note that BIOPAC systems without a MP150/160 exist, for example a logger). This unit is connected to power and through network cable to the PC on which the data is recorded. Note that the MP160 is a newer model than the MP150 and BIOPAC currently only sells the MP160, however, the MP150 can be used just as well.
   
• STP100C
  The STP100C is an isolated digital interface which main purpose is that it can receive digital inputs. This enables users to send markers from the stimulus PC (on which stimulus presentation software such as E-Prime or OpenSesame is running) to the BIOPAC system. These digital inputs (markers) can be recorded as signals. The STP100C also has digital outputs and an external trigger input. Note that the STP100C safely isolates the digital inputs and outputs to and from the MP system. 
   
• UIM100C
  The UIM100C (Universal Interface Module) is used to connect the physiological modules from the 100C series to the rest of the MP150 system. Note that this unit is used with MP150 systems, for MP160 systems the HLT100C is included. The UIM100C features 16 analog input channels and 2 analog output channels through 3.5 mm jack. For electrical safety reasons, when using the analog input channels, an Input Signal Isolator (INISO) is required! Do not plug anything in these channels, unless you absolutely know what you are doing!
   
• HLT100C
  The HLT100C (High Level Transducer) is similar to the UIM100C and comes standard with the MP160. It features 16 analog input channels and 2 analog output channels through RJ11 jacks. For electrical safety reasons, when using the analog input channels, an Input Signal Isolator (INISO) is required! Do not plug anything in these channels, unless you absolutely know what you are doing!
   
• AMI100D
  The AMI100D (Amplifier Input Module) is used to connect the smart amplifiers to the MP160 unit. It features 16 input channels and 2 output channels. For electrical safety reasons, when connecting external equipment to the AMI100D, make sure an INISOA is used for proper isolation. Do not plug anything other than the smart amplifiers in the AMI100D, unless you absolutely know what you are doing!

100C Series

Information

The 100C series amplifier modules snap on to the UIM100C or HLT100C and connect to the MP150/160 system. The 100C series modules are all wired (i.e. wires go directly from the module itself to the participant). Most (if not all) modules have settings on the module itself which can be altered with toggle switches. Normally, these settings are:

• Gain. A higher gain will amplify the signal more than a lower gain. When the signal is small, the gain can be increased. When the signal is high, it can be decreased.
• Low-Pass filter (LP). Filters the signal using a low-pass filter, i.e. it passes frequencies below the cutoff frequency. When there are multiple low-pass filters, the lowest low-pass filter will be applied to the data (see here).
• High-Pass filter (HP). Filters the signal using a high-pass filter, i.e. it passes frequencies above the cutoff frequency. When there are multiple high-pass filters, the highest high-pass filter will be applied to the data (see here).

Modules

• ECG100C 
  With the ECG100C one can measure electrocardiography (ECG). Usually only one module is used allowing for 1-lead measurements, which is suitable for QRS wave detection. The ECG100C module has the basic settings as mentioned above, plus the Mode setting. The Mode setting can be set to R-wave indicator (R-wave) or Normal (Norm). Normal outputs the ECG signal as is. When set to the R-wave indicator, the output signal will produce a smoothed positive peak every time the R-wave is detected. More information:
  • Protocol and instructions for measuring ECG.
  • See BIOPACs official ECG100C product sheet for more information.
     
• EDA100C/GSR100C
  With the EDA100C (or GSR100C, which is the older model, but works exactly the same) one can measure skin conductance. The EDA100C module has the basic adjustable settings (Gain, LP and HP). More information:
  • Protocol and instructions for measuring skin conductance.
  • See BIOPACs official EDA100C product sheet for more information.
     
• EMG100C
  With the EMG100C one can measure electromyography (muscle activity). One EMG100C module allows measurement of activity over one muscle/spot. The EMG100C module has the basic adjustable settings (Gain, LP and HP). More information:
  • Protocol and instructions for measuring fEMG.
  • See BIOPACs official EMG100C product sheet for more information.
     
• SKT100C
  With the SKT100C one can measure skin temperature. The SKT100C module has the basic adjustable settings (Gain, LP and HP). More information
  • See BIOPACs official SKT100C product sheet for more information.
     
• DA100C
  The DA100C is a general purpose amplifier, that can work with different transducers. The DA100C module has the basic adjustable settings (Gain, LP and HP). More information:
  • See BIOPACs official DA100C product sheet for more information.

BioNomadix

Information

BioNomadix modules are wireless systems with a small transmitter unit close to the participant, and a receiver unit which is used in combination with an MP150/160 unit, or alternatively with a logger (for field recordings). BioNomadix modules snap directly on to the MP150/160 or the STP100C. The BioNomadix receiver units have toggle switches, just like the 100C series modules. However, these toggle switches do not control gain and filter settings, but only channel selection. For more information, an overview of all BioNomadix modules and instructions on how to use them, see the BioNomadix series product sheet.

Important notes:

• Charging the transmitter. The BioNomadix transmitter units need to be charged. When charging, make sure the transmitter is turned off.
• Use transmitter and receiver in pairs. The transmitter and receiver unit are used in pairs and are not interchangeable. Make sure you have the correct transmitter with the correct receiver (check the serial number to verify).
• Interferences in data transmission. A good connection between transmitter and receiver is necessary for good data quality. Make sure that there are no obstructions between the transmitter and receiver and that the transmitter and receiver are not placed too far from each other. Unfortunately, the occurrence of short data transmission interferences cannot be excluded. These interferences are visualized by flat lines, at the value that was last being received. Usually these interferences are very short (one or a few samples) and will not influence the data significantly. 

Modules

• RSPEC
  With the RSPEC one can measure respiration and ECG.
   
• PPGED
  With the PPGED one can measure photoplethysmography (PPG) and skin conductance (or electrodermal activity, i.e. EDA).
   
• EMG2
  With the EMG2 one can measure two channels of EMG. This module can for example be used for facial EMG over the corrugator and zygomaticus muscles. 
   
• NICO
  With the NICO module one can measure impedance cardiography (ICG).

Smart amplifiers

The smart amplifiers are small amplifier units. Unlike the 100C amplifiers or the BioNomadix receiver units, they do not snap on to the side of the MP150/160 module. Instead, they are plugged into an Amplifier Input Module (AMI100D) and the AMI100D is plugged into the MP150/160 module. This allows for amplification of the signal close to the participant. Also, the Biopac module unit is kept relatively small. See the Smart Amplifiers product sheet for more information. 

Important notes:

• AcqKnowledge 5.0.5 or higher. To use smart amplifiers AcqKnowledge version 5.0.5 or higher is required. 
• Digital channel 15. Digital channel 15 is used for communication with the AMI100D and the smart amps. This has the following consequences:
  • Digital channel 15 must be set high when 1) AcqKnowledge is launched, 2) during channel setup when AcqKnowledge needs to detect the smart amplifiers, and 3) when the recording is started. When nothin is connected to the digital channels (such as a parallel cable for sending markers), the channel is normally set high. However, when something is connected, the software controlling it must set channel 15 high (normally this is bit 7, or value 128) during the beforementioned periods.
  • Digital channel 15 cannot be used as digital input channel. This means that when markers are sent through parallel port only 7 bits can be used instead of 8 and thus only values up to 127 can be used instead of values up to 255. See here for more information about setting up the marker channel in AcqKnowledge and here for more information about markers in general.

EL-CHECK

The BIOPAC EL-CHECK device is an electrode impedance checker device. This device should be used when impedance needs to be kept to a minimum to ensure good data quality. For example, its usage is recommended when measuring fEMG. An EL-CHECK device can be borrowed from SOLO through the Helpdesk. More information, including a video on how the EL-CHECK device works can be found here.

Resources

• MP Hardware guide (latest version can also be downloaded here)
• Other Biopac manuals can be downloaded here
• BIOPAC webinars