Siemens TRAFFIC CONTROLS TC12 사용자 설명서

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TC12 Installation, Commissioning & Maintenance Handbook 
666/HE/43100/000  
Page 189 
Issue 9 
6.5 MAINTENANCE 
6.5.1 Status LEDs 
LEDs are provided on the front edge of the board to provide basic status 
information. The position of these LEDs and their functions are shown in Figure 
34. 
 
A System fail on the Controller Main Processor PCB may indicate a fault on the 
Integral OTU PCB. 
 
If the system fail LED is on, information about the type of fault that has occurred 
can be accessed using a handset terminal (see section 6.4.2 on handset 
commands).  
Note:  The OTU may still be operating normally, even with the system fail LED 
on, depending on the type of failure that has been detected. 
 
If the Watchdog fail LED is illuminated the software is not running correctly and all 
transmission from the OTU will be halted. The only way to reset the board is to 
power off and then on again. 
 
The Transmit confirm LED is on whilst correctly formatted control messages are 
being received by the OTU, and the information is being transferred to the 
controller. If a valid control message is not received for 4 seconds the transmit 
confirm LED will go out. Note this LED does NOT indicate that a reply message 
has been sent. 
 
The Carrier detect LED should come on once a second for each control signal on 
the line (the LED is set by the software in response to the modem carrier detect 
output being set, it does not indicate that the carrier detected was a valid control 
message). 
 
6.5.2  Effect of Incorrect Switch Settings on the OTU PCB 
(1) S1 - 2/4 Wire Select Switch 
4 wire system but with 2 wire selected in error or 2 wire system but with 4 wire 
selected in error; the OTU may not receive the control signal and will not reply, 
therefore the carrier detect and transmit confirm LEDs will be OFF. 
 
(2) S2 - Lithium Battery On/Off Switch 
If this switch is off the system fail LED will illuminate on the Controller Main 
Processor PCB and the Integral OTU will not communicate with the Instation. 
 
(3) S3 - Line level switch 
A 6-way DIL switch is used to set line levels. If switch positions 1 to 4, of the DIL 
switch, are set incorrectly the OTU will transmit at the wrong output power.  
 
If switch positions 5 and 6 are set incorrectly the receive threshold for the OTU 
modem will be wrong. If it is set too low corrupted control messages may occur. If 
set too high the control messages from the Instation may be undetected.