Mindray BC-2800 - Testable Signals

Hardware
4. Drive/signal-detection circuit of the position transducers
The control system judges the motor positions by the signals sent by the
position transducers (photocouplers). The photocouplers are driven by the MCU
through a 74LS07. The photocoupler sends the position signals to the MCU
through a 74LS14 (inverter). See the figure below for the block diagram of the
position-detecting circuit. The photocouplers are installed on the sample probe
assembly and the syringe assembly and feed the control and feedback signals
to the driving board through cables.
1.7.2.4 Testable Signals
To test the signals, connect the grounding terminals of the oscillator and the
multi-meter to the DGND or the PGND.
The testable signals are: control signals of valves and pumps, sequence signals
of the motors, valves, position signals sent by the position transducers, serial
communication signals, reset signals and voltage signals of the power supplies.
BC-2800 Auto Hematology Analyzer (V1.0) 1- 13