Siemens SITRANS FUS1020, Manual, Page: 51 / 251

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1020NFM-1D Section 2
z
Press the <Left Arrow> to accept the Vs setting. The highlight moves to [Empty Pipe Set]. This
action indicates that the meter has accepted the new Vs setting and is now measuring flow.
Setting The Zero Flow Level
The [Zero Flow Adjust] menu cell becomes active after the meter completes the transducer install
procedure. When you invoke the Transducer Install, the meter performs an automatic routine (Auto
Zero) to establish a standard zero flow setting. However, AutoZero only supports the Reflect Mode
transducer mounting. It will be suppressed for a Direct Mode installation (like the example described in
this section). In addition, some conditions disallow the proper functioning of AutoZero even in Reflect
Mode. In such a case, the meter provides two alternate means of achieving a zero setting:
z
Actual Zero : requires zero flow in pipe.
z
ReversaMatic: obtain a zero by Xdcr reversal.
Zero Flow Adjust helps the meter to remove a possible zero offset due to pipe or transducer asymme-
try. Setting the zero flow level allows the meter to sense absolute flow direction and magnitude under
low flow conditions. Zero Flow Adjust also provides a ZeroClr routine to remove a zero offset setting
(done automatically or manually). In most cases, AutoZero works well and is desirable since it requires
no user input. When AutoZero is not possible, we recommend using the Actual Zero command. Actual
Zero requires you to stop flow to allow the meter to sense any zero offset. If not possible due to
application conditions, then the second alternative, ReversaMatic, allows zero level sensing when
liquid flow is at any velocity. However, you should use Actual Zero at the first opportunity. The ZeroClr
command instantly resets the zero flow registers to [0.000].
Performing The Actual Zero Routine
NOTE: Please reduce flow through the pipe to zero .
This example continues the sample application. We have successfully installed our C1H transducers
(in Direct Mode) and can stop flow for the purpose of performing an Actual Zero (see next page).
Siemens 2 Channel [1] SITE1
Transducer Model 1021 Xdcr
Transducer Size C1
Xdcr Mount Mode Reflect
Spacing Offset Invalid Flow
Number Index 4
Spacing Method Invalid
Ltn Value (in) 2.330
Install Completed? Install
Empty Pipe Set Chan Not Setup
Zero Flow Adjust Chan Not Setup
Drive 53 0 36 [6: :0]
Pick/Install Xdcr