
114
Using ProLink
®
Software with Micro Motion
®
Transmitters
Configure Menu: Transmitter Outputs
continued
Milliamp outputs
Added damping on
RFT9739 outputs
Use the Damp text boxes to put a secondary digital filter on milliamp
outputs from the RFT9739. The secondary filter adds damping to
internal damping on flow, temperature, and density. If two or three
outputs indicate the same variable, added damping enables more than
one damping value on the variable. Damping filters the effects of rapid
changes in the variable.
The added damping value is the coefficient of the secondary filter. The
actual time depends on many factors, including sensor type, density of
the process fluid, and the duration of the digital time constant. The
transmitter rounds down the entered value to the nearest available
programmed filter coefficient.
Table 10-2
lists programmed filter coefficients for added damping on
flow, density, and temperature as indicated by the milliamp outputs.
Table 10-2. Filter coefficients for added damping on RFT9739 milliamp outputs
Example:
Given:
The primary milliamp output from an RFT9739 indicates mass
flow, and has programmed limits of zero flow at 4 mA, and 100 grams
per minute (g/min) at 20 mA.
Problem:
Configure the output to go to 4 mA when the mass flow rate
goes below 2.00 g/min.
Solution:
Enter a value of 2.00 into the Cutoff text box under Milliamp 1.
An output of 4.32 mA indicates a mass flow rate of 2.00 g/min. The
primary milliamp output goes to 4 mA if the flow rate drops below
2.00 g/min.
Mass or volume flow Temperature Density
0
0.1
0.2
0.4
0.8
1.6
3.2
6.4
12.8
25.6
51.2
102.4
204.8
409.6
819.2
1638.4
0
2
4
8
16
32
64
128
256
512
1024
2048
4096
8192
16384
32768
0.5
1
2
4
8
16
32
64
128
256
512
1024
2048
4096
8192
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