Multi-Channel Meter Types; Arithmetic Operation; Multi-Path Operation - Siemens SITRANS F Operating Instructions Manual

Section 1 1010PFM-3G

Multi-Channel Meter Types

If your 1010 Model provides Multi-Channel Mode it offers you two independent measurement channels.
The meter's resources are divided among these channels equally. This means that analog Input/
Output, relays, and digital command lines will be fewer than for single channel machines. We will
show you later how to "get around" this limitation for cases where you need all the meter's resources
for a single measurement channel. Your datalogger and site storage, being bulk resources, are not
divided up at all, and remain available for each channel's use. You will be able to Save and Recall
sites to and from the various channels as long as they share an identical measurement technology
(Reflexor, clamp-on, flowtube, etc.). Be aware, however, that moving a site from one channel to an-
other like this, will likely require a new Initial Installation to achieve its best potential. This is especially
true if the new target installation is not on the same pipe or uses another pair of transducers. Note that
datalogger reports will be interleaved in memory and their frequency is controlled by the interval that
was selected for each channel. Providing each site with a unique name will enable you to sort these
out when analyzing the data later.

Arithmetic Operation

The dual channel instruments provide a modality of operation which permits the user to arithmetically
combine (through addition or subtraction) the results of the two independent measurement channels.
Installation of each channel is done via the dual channel menu. Site Saving and Recalling automati-
cally recall the contributing sites. While the displays for each physical channel provide you with all the
data (flow rate, totals, etc.) that are provided via independent channel operation, user Input/Output is
largely oriented toward the virtual channel—Channel 3.

Multi-Path Operation

In many cases, the performance of an ultrasonic transit time meter can be improved by allowing it to
interrogate the flow field with more than one beam. Imperfect flow profile conditions such as non-axial
or cross-flow or an off-center higher-rate flow core, which can cause a single path machine to mis-
report the flow rate, are often remedied in this way. The multi-path installation is similar to arithmetic
operation, except for the fact that the virtual, or output, channel has pipe dimension attributes which in
the arithmetic meter channel it does not. This means that when you install a multi-path meter, pipe
data MUST be installed in Path 3. Your 1010 facilitates this by copying pipe data that you install in Path
3 to the other paths. It is seldom, if ever, necessary to "trim" the pipe data for the individual path
channels—although you may install different size or type transducers for each path. Once you define
the pipe, move the menu to the individual paths using Select Path for the physical installation of each
channel. This is accomplished in the same way that individual channels are installed.
Save and Restore Operations for multi-path sites execute on all the component channels simulta-
neously—the individual paths of multi-path sites do not have any existence or autonomy as single
channel sites. You will also find that individual path channels possess a reduced set of user-acces-
sible menu functions. For example, although you may zero each individual path, the meter provides
Kc control (slope correction) for the virtual channel (system channel) only. You will find that the fea-
tures and functions provided for each physical channel sensibly focus on the physical measurement
task. User output data, however, is largely reserved for the virtual or system channel. This includes the
totalizer functions, analog outputs, and datalogger. In some instances, access is provided to the path
channels data as well to facilitate the gathering of diagnostic data. While minimizing menu clutter, we
have tried to preserve as much functionality as practical. Totalizer control via lead-in function key is
provided by <F3> for the dual path meter.
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