Q about Medical Equipment - Patient monitor

[ericmar]

Dear all,

May I know if anyone here has experiences in interfacing with the patient monitor especially the Press connection part? Currently, I m studying about how to emulate a circuit which would function like an Invasive Blood Pressure (IBP) transducer. However, this circuit fails to work with some of the patient monitors, for e.g. the Phillips monitor. Basically, an IBP transducer is designed based on a wheatstone bridge and there are only 4 lines from the transducer, namely the E+, E-, S+ and S-. E+ and E- and for the Excitation voltage which works like the supply for the IBP transducer while S+ and S- work as the output signals to the device it connects to, a patient monitor. According to some medical standards, the impedance across S+ and S- should not be less than 300Ω.

My problem here is: "How does a patient monitor (those smart one) detect whether or not a transducer has been connected to it?"
Do they check the impedance across the S+ and S- of transducer? If not or not only that, then what do they check to confirm the existence of a connected transducer?

Apparently there are not much detailed information about how a patient monitor works on the web, and thus, makes me hard to diagnose my problem.

I really hope someone here who has more experience on this could enlighten me a bit. Also, it would be great if someone can explain to me in detail how the wheatstone bridge works and how an IBP transducer works if possible.

Thanks million!

Best regards,
Eric Mar

 

[Iouri]

you might also put like small amount of current through thepatient to detecy patient presence and if it is something like 50KHZ that you dont need to worry if it is affect your BP messurements



Good Lack

 

[ericmar]

you might also put like small amount of current through thepatient to detecy patient presence and if it is something like 50KHZ that you dont need to worry if it is affect your BP messurements



Good Lack

Sorry, I dont quite get u.

Excitation voltage (E+, E-) is provided by the patient monitor, and it is in fact, I want my circuit or device to be detected by the patient monitor rather than I detect the presence of the monitor.