User's Manual

Introduction to the TTMS System
TTMS Reader
Tanker Truck Monitoring System- User’s Guide 13
1.3.4.2 Protection Unit
The Protection unit is located in the truck's cabin. It interfaces between the AVL Reader and the
Seal Status Indicator, filtering the AVL Reader signal and splitting it in installations with two Seal
Status Indicator units. (The Protection Box is transparent to the system.)
Interface to the AVL Reader and to each of the Seal Status Indicators is provided via RS485
communication. The output interface to the Seal Status Indicators include a +12V regulated
power line.
NOTE: The power and RS485 signals are delivered to Display unit via fuses and other protective
components in order to provide Over Current and Over Voltage protection.
The Protection Box is shown in the following figure.
Figure 1-6. Protection Unit
Table 1-8. J1 Connector Pinout Table 1-9. J2/J3 Connector Pinout
Pin Signal
1 NC
2 RS485 COMM
3 -Vin (GND)
4 RS485 B
5 RS485 A
6 +Vin (+24VDC) EXT Input
Pin Signal
1 -Vout (GND)
2 RS485 COMM
3 NC
4 +Vout (+12VDC)
5 RS485 B
6 RS485 A
Connection to
AVL Reader
Connection to Seal
Status Indicators
Groundin
g
Terminal