AR-FN2 (serv.man10). ARFN2 Service Manual-Circuit Descriptions - Sharp Copying Equipment Service Manual (repair manual). Page 5

FSS is the sensor same as the transport entry port sensor (PIS). 
The document full state on the treatment tray is detected by the douser liked with the tray movement. The light path is interrupted when document
full. 
The signal is passed to the G/A (IC5-39 pin) through the noise filter of R1 and C3. 
Logic of the signal inputted to the G/A: Document tray full detected 

®

 H, Document tray full not detected 

®

 L

R39 is the current limiting resistor of LED. R52 is the sensor load resistor. 

TLS is the sensor same as the transport entry port sensor (PIS). 
The tray bottom (limit) is detected by the douser liked with the tray movement. The light path is interrupted when "Limit." The signal is passed to the
G/A (IC5-41 pin) through the noise filter of R4 and C6. 
Logic of the signal inputted to the G/A: Limit detected 

®

 H, Limit not detected 

®

 L

R40 is the current limiting resistor of LED. R53 is the sensor load resistor. 

PLS is the sensor same as the transport entry port sensor (PIS). 
The paper level on the tray is detected by the lever-system actuator. The light path is interrupted when "Paper level detected." The signal is passed
to the CPU (IC9-75 pin) through the noise filter of R10 and C15. 
Logic of the signal inputted to the CPU: Paper level detected 

®

 H, Paper level not detected 

®

 L

R44 is the current limiting resistor of LED. R66 is the sensor load resistor. 

Full stack sensor input circuit

Full stack sensor
(FSS)

Limit sensor input circuit

Tray Limit sensor
(TLS)

paper surface sensor input circuit

Paper surface sensor
(PLS)

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