Omega Vehicle Security manual Voltage Input Scaling, Matching Transducers to the OM-550

4.14 VOLTAGE INPUT SCALING

Any of the input channels (1 through 5) may be programmed as Voltage channels. Each Voltage channel includes unique m and b constants for "scaling" data to your application. These constants default to +1.00000 and 000000, respectively, when the channel is first programmed as a Voltage channel but the user may reprogram them as necessary. The following pages include examples for common transducers.

4.14.1 MATCHING TRANSDUCERS TO THE OM-550

Some transducers provide a "voltage" output; others provide a "current" output. This section explains how to use resistors to match either output to the input.

Currents must be converted to a voltage and voltages must be attenuated (reduced) if they can exceed the maximum input (±2.0000 VDC). This process is called Matching, which means converting or attenuating the transducer's output to an acceptable level without overloading it.

4.14.2 MATCHING A VOLTAGE TRANSDUCER

Use two resistors to attenuate a voltage without overloading the transducer. The

method shown here will draw approximately half of the transducer's maximum current at full-scale.

I

+ R2

TRANSDUCER V R1 OM-550 INPUT

OUTPUT

-

Figure 4-8

V= transducer maximum output voltage.

I= 1/2 transducer's maximum output current.

R1 = 2 / I

R2 = (V-2) / I

The ±10 Voltage Probe (P/N E29-0050-35) uses this technique to attenuate ±10 VDC signals to the input range of ±2 VDC.

OM-550 u32u