Terumo BCT Trima Accel, Руководство по обслуживанию

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Figure 2-26: Valve position sensor window and infrared LED light
Not related to normal valve function, but could impact function: The raised cassette and lowered
cassette position sensor signals pass through the valve CCA; however, the +5.0 V LED power and
+5 VCC are shared lines with the valve position sensors and LEDs.
Control CCA (End)
The valve position bits are sent to the control CCA FPGA and the safety CCA FPGA, where the
system identifies the measured position. When the commanded position is reached, the control
computer stops the valve movement by toggling the enable bit of the selected valve to
off
, which
removes the power connection from the H-bridge circuit to the motor.
The control and safety systems are both looking for the position sensor bit to confirm the position
of the valve. They must both agree on the position, or an alarm is generated. As a redundant safety
mechanism, the control and safety systems are also calculating the time between when the valve
starts moving (enable bit is sent) and when it stops moving (position bit is received). The timing of
when the valve reaches its commanded position is also one of the variables used to determine the
accrued volume in a product bag.
Safety CCA
The position sensor LED power is generated on the safety CCA. The FPGA on the safety CCA
performs an LED test at start-up and every 60 seconds during a run. The test is as follows:
Valve System
Trima Accel
®
Automated Blood Collection System • Service Manual 2-35