Omega Vehicle Security DRA-DCC-8 manual Serial Control Mode, E Enable Terminal, RS422 Termination

6.2 THE "E" (ENABLE) TERMINAL

For E="1" the unit is enabled, which means that all input vectors are received and the output is updated. When E="0" the unit ignores any new input vector. The E terminal is recommended to be used as a strobe for parallel data which has a long setup time. In this case the following sequence is recommended: prior to applying a new vector, the E terminal should be set to logical 0 (inhibit state), then the new input vector should be imposed. Once the new data is set, the E terminal should be pulsed.

The E terminal is also used for multidrop configuration. The 15 bit vectors are applied to the units in parallel and the selection is carried out by controlling the "E" inputs.

7. SERIAL CONTROL MODE

7.1 RS232c / RS422 SELECT

he DRA-DCC-8 is equipped with two serial communication ports: The RS232c and the RS422. A jumper switch at the right side of the DIP switch array is used to select the required communication type. See figure 3.

RS-422

7.2 RS422 TERMINATION

Figure 3.

RS-232c

The SW8's ON state terminates the RS422 receiver terminals with a 100W load. In a multidrop configuration, the last (most distant) DRA-DCC-8 unit should be terminated in order to match the transmission lines.

Note: Only one termination load per RS422 communication link is permissible.

7.3 SERIAL CONTROL SWITCH SETTINGS

S1	S2	S3	S4	S5	S6	S7
BAUD RATE			ID CODE		*	ON

* according to para #5.2

7.4 SERIAL COMMUNICATION PARAMETERS

The communication protocol is 8 bit ASCII, even parity, and one stop bit.

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