MRI CBL/FILTER SYS. TO BIOPOT. AMPS - MECMRI-BIOP

Cable length:

10 m total (8 m + 2 m)

MECMRI-2:

MRI control room cable. Supports one channel of subject biopotential connection and is 2 meters long. The cable incorporates a plastic housed DSUB9 Male connector to panel mount with the control room exposed DSUB9 female connector of the MRIRFIF interference filter.

MRIRFIF set:

Five line Pi filter set, designed for interfacing between the MECMRI-1 chamber room cable and any of the MRI Control room cables (MECMRI2-MECMRI6).

•  MRIRFIF: -3 dB point = 100 kHz
• MRIRFIF-2: -3 dB point = 1 MHz
• MRIRFIF + MRIRFIF-2 = 3 dB point = 70 kHz
  • attenuation is -60 db from 7 MHz to 1000 MHz
  • attenuation slope from 70 kHz to 7 Mhz is 30 dB per decade

The MRIRFIF’s symmetrical construction, with dual 9 pin female connectors, results in a pin swap for pins 1, 2, 3, 4, 5, regarding signal flow as illustrated here:

Accordingly, if the MRIRFIF and associated cable assemblies (such as MECMRI-#) are used with any existing patch panel connectors, the existing connector must be a Male/Female 9 pin straight-thru DSUB patch or filter connector. The Male side of the existing connector must be on the Control room side to successfully connect the MRIRFIF to this connector.

Best performance is obtained by robustly attaching the GROUND of the MRIRFIF (metal enclosure) to EARTH GROUND at the junction panel. Mounting the MRIRFIF to the junction panel via the included L-bracket establishes an excellent ground to the panel. EARTH GROUND must be robust and held to the same potential as MAINS GROUND.

Leakage Currents
The IEC 60601-1 standard specifies a leakage current of 5 ma assuming double fault conditions. 265 VAC at 60 Hz will source 5 ma into a reactance of 53 K. This reactance is equivalent to an effective subject capacitance to equipment ground of 0.05 uF. The BIOPAC MP unit establishes a subject to ground capacitance of 0.005 uF. The Pi filter set (MRIRFIF + MRIRFIF-2) incorporates a 0.003 uF subject capacitance to ground. Accordingly, even with 15 MECMRI cables—with 15 MRIRFIFs—this results in a capacitance of .05 uF, which is 100% of the IEC 60601-1 limit, assuming mains is 265 VAC at 60 Hz.

MECMRI-1:

MRI chamber room cable. Supports one channel of subject biopotential or transducer connection and is 8 meters long. The cable incorporates a plastic housed DSUB9 Male connector to panel mount with the chamber room exposed DSUB9 female connector of the MRIRFIF interference filter.

MRI compatible:

Yes, cables incorporate some metal parts, but no ferrous parts, and are considered MRI-Compatible. See MRI, Radiotranslucent, and Radio-opaque Compatibility.