CA-500 Series S/M 3-8 Revised December 2001
8
3.4 PCB No. 2133 (THERMO; Thermister)
3.4.1 Function
This board is used to mount the thermister.
Centigrade temperature sensor IC (LM35DZ) is used for the thermister.
3.4.2 Setting and Adjustment
Setting and adjustments are not necessary.
3.4.3 LED and Test Point
There are no LEDs or test point.
3.5 PCB No. 2134 (Y-Z RELAY; Liquid Surface Sensor, Probe Crash,
Y-Axis Home Position Sensor, Z-Axis Relay)
PCB No. 2157 (Y-Z RELAY2; Liquid Surface Sensor, Probe Crash,
Y-Axis Home Position Sensor, Z-Axis Relay)
3.5.1 Function
This is the detection circuit of the liquid surface sensor which uses the capacitance change method in
which liquid surface is detected by capacitance change when the probe touches the liquid surface. This
circuit also has the Probe Crash Detection, Y-Axis Home Position Sensor, and relay to the Z-Axis signal.
(1) Liquid Surface Detection Circuit
Liquid surface of sample, reagent, buffer or rinse water is detected and a detection signal is
issued. Detection signal is also issued when the probe is removed from the liquid surface.
(2) Probe Crash Detection Circuit
Probe crash is detected and a probe crash signal is issued.
(3) Probe Arm Y-Axis Home Position Sensor
(4) Probe Arm Y-Axis Motor Signal Line Relay
(5) Relay to PCB No. 9264 (Z RELAY)
3.5.2 Block Diagram
Figure 3-6: PCB No. 2134 and 2157 Block Diagram
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