Fukuda Denshi HS-8000 Series, Service Manual

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Mother Board Circuit Explanation
Mother board is an interface board to HSA-80 and supplied power from the HAS-80. The mother
board has several functions other then the above and its function is classified into the following
blocks.
Hot-swap circuit
Assuming the use of HS-8000 hot-swap, hot-swap circuit is set up. Even if the overcurrent is
detected and Power FET is blocked, the circuit automatically retries the operation. When the
overcurrent continues 10ms or more, the power FET of power supply line is blocked.
DC/DC Converter
Converting power supply form HSA-80 into DC/DC, the power supply is used for analog output
circuit power supply and non-isolation parts of ECG amplifier and Multiamplifier boards. Also, the
converter can be used as digitally driven power supply of Gas Unit I/F.
Module-LAN Interface Circuit
Pulse transformer for Module-LAN interface is set up.
Analog Output Circuit
Analog waveforms of ECG waveform 1CH and IBP waveform 2CH are outputted. Serial interface
signal from CPU board is converted into D/A and outputted. Also, analog output part provides basic
insulation (withstanding voltage 1.5kV) Specification of analog output is as follows
Range of Output Voltage
：
±4.5Vp-p
ECG Output Size ： 1mV ECG/1V
IBP Output Size
：
100mmHg/1V
Output Accuracy ： ±10 ％ (not including offset error)
Offset Error
：
Within ±100mV
Delay ： 35ms or less
ECG: Monitor Mode, Diagnosis Mode, IBP
：
When LPF is set to 40Hz.
QRS Sync. Signal Output
Digital signal synghronized with QRS detection of the ECG waveform is outputted. Specification of
Synchronization output is as follows.
Hi level ： +4.3 to +5V±5%
Lo level
：
0.3V or less
Delay ： To 70ms wide QRS simulated triangle wave,
・
100ms or less (From QRS simulated waveform rise)
・ ±35ms or less (From QRS simulated waveform peak)