Siemens SITRANS FUS1020, Руководство пользователя, Страница: 17 / 251

1-6
1020NFM-1D Section 1
Channel 1
Channel 2
Ch1- Ch2
Output
(difference of
Ch 1 & Ch 2)
PIPE `A'
PIPE `B'
PIP
E `
A' F
LO
W
R
AT
E
PIP
E
`B
' F
LO
W
R
AT
E
Virtual
Channel
3
Channel 1-2 Flow
Channel 1-2 produces a data output via a virtual channel 3, proportional to the difference of the flow of
two independent pipes. This requires setting the two flow channels to operate independently. Note that
you can still select the individual channel outputs with this configuration.
Virtual
Channel
3
Channel 1
Channel 2
Ch1 + Ch2
Output
(sum of
Ch 1 & Ch 2)
PIPE `A'
PIPE `B'
PIPE “A” FLOW RA
TE
PIPE “B” FLOW RA
TE
1.4 CLAMP-ON TRANSIT-TIME THEORY OF OPERATION
Note that in the figure below, two transducers are mounted to the outside of a pipe. If we identify the
direction of flow through the pipe, you can see that one transducer location is “upstream” and the other
transducer location is “downstream” with respect to the direction of flow.
Upstream
Transducer
Downstream
Transducer
FLOW FLOW