BRUEL & KJAER VIBROCONTROL 8000 - 22.2.3 Verifying Process Variable

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VC-8000 MPS
Content
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22.2.3 Verifying Process Variable
Figure 22-3) Process Variable Test Set Up
The UMM converts the input currents to voltages through a 249-ohm resistor. For the default
transmitter ranges (e.g. Top Scale = 20 mA, Bottom Scale = 4 mA), vary the power supply input over
the Process Variable input range according to Table 21-1.
The measured value will be:
 = (
(
 −  
)
ℎ
(
 − 
)
) + 
Where Input Voltage is the input power supply voltage, Full Scale is the maximum transmitter output
in Engineering Units, Bottom Scale is the minimum transmitter output in Engineering Units and the
Full Scale Voltage Changes is as shown in Table 21-1.
For example, an Input Voltage of -3 Vdc is input into a UMM channel configured for a 4 to 20 mA
transmitter that outputs 4 mA at 0 PSI and 20 mA at 100 PSI.
 =
−3  −
(
−1
)
−4
(
100  − 0 
)
+ 0  = 50 
Transmitter Type
Bottom Scale Input
voltage
Top Scale Input
Voltage
Full Scale Voltage
Change
UMM Power 4 to 20 mA
-1 V
-5 V
-4 V
Externally Powered 4 to 20 mA
+1 V
+ 5 V
4 V
0 to 5 V
0 V
+ 5 V
5 V
+1 V to 5 V
+1 V
+ 5 V
4 V
0 to -10 V
0 V
- 10 V
10 V
Table 22-1) UMM Process Variable Input Voltage Ranges
If you change Bottom Scale Input or Top Scale Input values, you will need to recalculate the FullScale
VoltageChange and the BottomScaleInputVoltage
VC-8000
UMM