Omega Vehicle Security DAQ-16 J3

The digital to analog (D/A) section of the D AQ-16 consists of two independent 12-bit

multiplying D/A converters, and two independe nt two-stage output ampli fiers. Digita l data,

(output to the D/A converter by the CPU), is converted to an analog voltage by the D/A

converter, amplified by the output ampli fiers and be comes output to the 62 pin connector at

CN1. The D/A converters used on the DA Q-16 ar e 12- bi t resol ution converter s. Of the 16 bi ts

written to the D/A, only the 12 least signifi cant bits (D0 - D1 1) are used for the conversi on.

The 4 most significant bits (D12 - D15) are ignored.

The DAQ-16 implements multiplying D/A converters w hich makes the analog output

proportional to a reference voltage applied to the D/A. Under nor mal circumstances, the

reference voltage should be applied from the internal +5V reference source. An external

reference voltage may also be supplied to the D /A. This input from the D-62 connector should

not exceed 5 volts and has a typical input impedance of 7.5Kohms. The D/A reference voltage

source is selected using jumper J3 as illustrated in Figure 2-4.

4 5 6

1 2 3

D/A channel 0 reference

External Source

Internal Source

D/A channel 1 reference

Figure 2-4. Jumper J3 Configuration

The D/A converter channels may also be operated in unipol ar mod e: 0 to +5 vol ts, or bipolar

mode: -5 to +5 volts. The output mode is selected using jumper J4 as shown in Figure 2-5. In

addition, a gain selection jumper is provided to select an output gain of 1 or 2. When using

an external voltage reference, this gain can b e used to amplify the D/A output for small

reference voltages.

WARNING: When the internal voltage reference is used, the D/A gain MUST be set to the

gain = 1 position.

DAQ-16 Users Manual 14