User guide
SENSORRAIL IIIE  8200-0593-03, REV. A 
SERVICE GUIDE
2 of 34 
Theory of Operation 
Trolley CPU 
The CPU in the trolley filters command data from a 
matrix switcher or controller. Movement along the 
rail is accomplished by sending an IRIS or FOCUS 
command. This command is sent to the dome 
camera by the matrix switcher, which the trolley 
CPU converts to left and right instructions. 
Note: To the matrix switcher, the trolley CPU board 
is transparent. However, some commands are 
delayed compared to what is typical for a dome 
camera’s response. 
This section describes the CPU to help you 
perform maintenance efficiently. It does not provide 
detailed information on internal electronic 
components. 
Board Layout 
Refer to figures on pages 7 and 8. 
The CPU board manages all trolley functions. The 
main CPU functions and components are as 
follows: 
•  Main connector: Provides power to the motor 
and receives data from the encoder and the 
dome (RS-422 bi-directional communication). 
•  Power connector: Receives 27Vdc and RS-
232 data provided by the four sliding collectors. 
•  Five LEDs: Enable quick diagnostics in case of 
technical problems. 
•  RF 2.4GHz transmitter board: Replaceable by 
removing four soldered attachment points. 
•  RF 2.4GHz emitter connector: Provides power 
and composite video signal to RF link emitter. 
•  BNC connector: Receives composite video 
signal from the dome. 
•  ATMEGA 128 microcontroller: Receives all 
external data and drives the motor. 
•  Electronic brake devices: A relay and a 
resistor that slow the motor by applying 
resistance to the motor. 
•  Optical sensors: Detect optical strips at the 
beginning and the end of the rail. 
•  JTAG connector and DIP switches: Used for 
factory programming and future features. 
CPU Connections 
Power connector (J1) 
Pin Function 
1 27Vdc 
2 0V 
3 RS-232 TX 
4 RS-232 RX 
Main connector (J2) 
Pin Function 
1 Not used 
2  RS-422 TX– to Dome 
3  RS-422 TX+ to Dome 
4  RS-422 R to Dome 
5  RS-422 RX+ to Dome 
6  27Vdc to Dome 
7  0V to Dome 
8  VB channel (encoder) 
9  5Vdc to Encoder 
10  VA channel (encoder) 
11 SC Synchro (encoder) 
12 Not used 
13 Motor – 
14  Temp probe (future) 
15 Not used 
16 Motor + 
Transmitter connector 
Pin Function 
1 5Vdc  
2 GND 
3 12Vdc 
4 GND 
5  Composite video IN 
6 GND 










