Omega Vehicle Security DRA-DCC-8 manual Multidrop Configuration, Putting the Unit Into Operation

8.1 SELF TEST #1 (Communication Ports Test)

In order to test the serial communication ports, this test mode converts the unit to a transponder for ASCII characters. Any transmitted character will be echoed to the host terminal. The host parameters should be set to:

Baud rate : 4800, Word length: 8 bits, Parity: even, Stop bit: 1

8.2 SELF TEST #2 (Same Leve)l

In this test mode, the DRA-DCC-8 unit ignores the address field. All the outputs are set according to the data field only.

8.3 SELF TEST #3 (Saw Tooth)

In this test mode, only one output channel (according to the address setting) will produce a saw tooth wave form in which the whole value range is used.

9. MULTIDROP CONFIGURATION

Up to eight DRA-DCC-8 units can be installed in a multidrop configuration using the RS422 communication port.

The controller's RS-422 transmitter is connected to the units' receivers while the controller's RS-422 receiver is connected to the units' transmitters.

As the communication cable might be several thousand feet long, it is necessary to terminate the end of the line with its characteristic impedance in order to avoid reflections in the transmission line causing data distortion. SW8 in its ON state terminates the Rx inputs with a 100Ω load.

10. PUTTING THE UNIT INTO OPERATION

The DRA-DCC-8 is supplied with a set configuration for parallel control mode. The DIP switch setting is:

MODE	S1	S2	S3	S4	S5	S6	S7
PARALLEL 4-20mA	OFF	OFF	OFF	OFF	OFF	ON	OFF

The communication port selector (see para #7.1) is set to RS232C. The unit should be set up according to the required configuration.

Before applying voltage to the unit see para #4 for power supply consideration.

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