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Water & Wastewater Asia September/October 2019

Water & Wastewater Asia is an expert source of industry information, cementing its position as an indispensable tool for trade professionals in the water and wastewater industry. As the most reliable publication in the region, industry experts turn this premium journal for credible journalism and exclusive insight provided by fellow industry professionals. Water & Wastewater Asia incorporates the official newsletter of the Singapore Water Association (SWA).

Water & Wastewater Asia is an expert source of industry information, cementing its position as an indispensable tool for trade professionals in the water and wastewater industry. As the most reliable publication in the region, industry experts turn this premium journal for credible journalism and exclusive insight provided by fellow industry professionals. Water & Wastewater Asia incorporates the official newsletter of the Singapore Water Association (SWA).

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32 | INSIGHT<br />

Communicative trends in<br />

process automation<br />

By Peter Lindmueller, Industry Manager, <strong>Water</strong> & Waste <strong>Water</strong>, Endress+Hauser<br />

The current standard for<br />

signalling the measured<br />

values generated by the<br />

instrumentation (measurement<br />

line) is the analogue current<br />

interface. This method maps<br />

the measured value to a loop<br />

current. 0 or 4mA corresponds<br />

to the lowest, 20mA to the<br />

highest reading that you<br />

want to transmit. Current<br />

interfaces offer the advantage<br />

of high interference immunity, a<br />

starting motor does not bother<br />

them, for example, but they only allow the<br />

representation of measured values within<br />

very narrow limits. The user does not get any<br />

information on the status or other conditions<br />

of the measuring point. Sometimes the<br />

information is enhanced by having an alarm<br />

relay for the status, but the overall content<br />

is very limited.<br />

In the end, it’s difficult to talk about<br />

communication at all.<br />

Why are operators and users interested<br />

in the details of instrumentation<br />

statuses? Where are the propellants for<br />

communication, where does the desire to<br />

know more about the process come from?<br />

Essentially, there are two reasons behind<br />

this:<br />

• There are more and more remote<br />

installations (satellites) that need to run<br />

24/7 but are staffed only at certain times<br />

or not at all.<br />

• Less staff with deep process and<br />

instrumentation skills is available.<br />

Due to both reasons, plant operators<br />

need to get deeper insight into the plant<br />

in the future and must be able to assess<br />

its functioning and the potential of<br />

defects from a distance.<br />

There are further trends that drive the<br />

need for deeper process knowledge:<br />

• Cost pressure: Plant operation and<br />

maintenance in the context of limited<br />

financial budgets.<br />

• Information needs: A city mayor might<br />

be asked in a budget round discussion<br />

if a facility is used to capacity, how<br />

effective and how efficient it is. Here,<br />

a qualified answer is expected which<br />

means that the above mentioned KPIs<br />

(Key Performance Indicator) must be<br />

ready at hand.<br />

• Planning needs: Deployment of expert<br />

emergency services is expensive. All<br />

assignments that can be moved from the<br />

non-plannable to the plannable zone<br />

allow a more favourable cost calculation.<br />

• Greater linkage between professional<br />

and private aspects: Although<br />

professional and private life do not<br />

merge into symbiosis, they are getting<br />

closer. Operators are, for example, able<br />

to do a remote evaluation<br />

of the system from<br />

their home while caring<br />

for their children. In<br />

other words: The digital<br />

twin of the system is<br />

available on their<br />

smartphone, tablet, or<br />

computer displaying the<br />

real conditions of the plant.<br />

It is not just about a measured<br />

value and a status, but about<br />

much more information on<br />

the measuring point.<br />

“How are you?” Describes an information that<br />

goes much deeper than the pure measured<br />

value and describes the state of the measuring<br />

point. This can range from “everything ok”<br />

to “cannot do any more”, it can contain<br />

references to the status of consumables<br />

(e.g. 20 per cent of the bottle’s detergent<br />

has been used up) and it can of course<br />

contain information about the measured<br />

value quality, e.g. my last calibration was<br />

60 days ago and must be renewed in<br />

30 days.<br />

Regular calibrations can be:<br />

• forced by authorities<br />

• necessary to optimise process flows<br />

Very often we can distinguish between<br />

process-optimising measurement<br />

(operational measurement) and product<br />

quality determination. While processoptimising<br />

measurement supports optimised<br />

usage and dosing of excipients for example,<br />

the second measurement describes the final<br />

product quality, or the quality of the raw<br />

materials used.<br />

<strong>Water</strong> & <strong>Wastewater</strong> <strong>Asia</strong> • <strong>September</strong> / <strong>October</strong> <strong>2019</strong>

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