Sensaphone SCADA 3000 Users manual - Manual (Page 272)

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SCADA 3000 User’s Manual
• If you run the cable in a metallic wireway or conduit, keep the communications
cable at least 3 inches from AC power lines carrying less than 20A, at least 6
inches from lines greater than 20A, and 1 foot from lines greater than 100KVA.
Running the communications cable through conduit provides extra protection from physical
damage and electrical interference. If you route the cable through conduit be sure to ground
the entire length by connecting it to the building earth ground. For best results, use ferromag-
netic conduit near critical sources of electrical interference. You can use aluminum conduit in
non-critical areas.
module Address
Each module must be configured with its own unique address using the BUS ADDRESS
jumpers. You may mix & match up to 15 modules to suit your application’s requirements. The
example below shows a Bus Address setting of 9.
Address Jumper Code
1 A B B B
2 B A B B
3 A A B B
4 B B A B
5 A B A B
6 B A A B
7 A A A B
8 B B B A
9 A B B A
10 B A B A
11 A A B A
12 B B A A
13 A B A A
14 B A A A
15 A A A A
Figure 5: Setting the Bus Address
Bus Termination
Located on each module is a jumper labeled BUS TERM. This jumper is used to terminate
the 4-wire communications bus.
Figure 6: Bus Termination jumper
Termination is required at the extreme ends of the communications network to minimize
signal reflections that would otherwise cause data communication errors. To activate the Bus
Termination, move the jumper to the IN position. Note that this should only be activated if the
module is at the very end of the network. All other modules in between should have the ter-
mination set to the OUT position. As a result, only 1 module (plus the main unit) should ever
have the termination activated. The diagram below illustrates proper termination of the com-
munications bus.