Omega Vehicle Security OM-550 manual Matching and Scaling a Voltage Transducer

4.14.5 MATCHING AND SCALING A VOLTAGE TRANSDUCER

EXAMPLE: Given a 20 - 90 % RH (Relative Humidity) transducer with a 0 - 10 VDC output at a maximum current of 3 mA.

Program the OM-550 to indicate 20.00 %RH to 90.00 %RH (that is, to indicate %RH with 0.01% resolution).

If a ±10 Voltage Probe is being used, begin with step 3, below. (This probe is already matched to the OM-550).

1.First, find the Matching resistors: I = 1/2 maximum current

=0.003 / 2

=0.0015 Amps

R1	= 2 / I	R2 =	(V - 2) / I
=	2 / 0.0015	=	(10 - 2) / 0.0015
=	1333 Ω	=	5333 Ω
2. Check:
V=	(R1 + R2) * I	V =	R2 * I
=	(1333+5333)*1.5 mA	=	1333*1.5 mA
=	9.999	=	1.9995
=	10	=	2

With these matching resistors the OM-550 will see a max 2 VDC at the Transducer max output of 10 VDC.

OM-550 u35u