June 2008

CCST review

I provide technical support for Industrial Controls Distributors and took a break from my homework (toward my BS EET) to read the May issue of InTech. I multi-task on a daily basis, and I need to write about your recent CCST review question. I believe the question scenario would indicate our final control device to have a linear trim characteristic (answer: D) in place of the posted Equal Percentage (answer: B).

If you note in the manual (see www.isa.org/link/herculinePDF), this illustrates the Quick Opening (answer: A) and Equal Percentage (answer: B), whereas Throttling (answer: C) is not applicable, and Linear (answer: D) is pretty self-explanatory.

Equal Percentage (Adobe, pg: 52) (Printed, pg: 42)

Quick Opening (Adobe, pg: 53) (Printed, pg: 43)

My bet is this was a typographical error that missed editing, but I felt obligated to bring this to your attention.

Bobby Bruzina, Cincinnati, Ohio


Thanks Bob,

You are correct, and we made a mistake with the answer. Thank you for your contribution.


Nicholas ShebleInTech Senior Technical Editor

Valuing the team

Congratulations for this nice thought provoking editorial in February InTech's "Talk to Me."

Every phrase is very relevant. Team work, communication, combination of speed and perseverance, existing technology, introducing new technology-everything is relevant and equally important.

To improve and enjoy fruits of new technologies, we need to keep introducing new technologies at regular interval to ensure smooth transition of operation and control and ensure our people get transformed to new technologies and do not remain addicted to time tested older technologies.

At the same time, some portion of old technology will remain in the system, and we have to ensure its maintenance and adaptability to new generation. It is very important to ensure the new generation is able to realize the importance of these and become part of maintaining the older technology along with new technologies.

It is easier said then done. The realization comes when during annual maintenance we ask people to maintain termination, transmitters, or control valves; they will murmur why they are not given opportunity to maintain DCS, PLC, or other control room system. Maybe we are also at fault to some extent as we tend to associate more importance to the people associated in control room works.

Both jobs are equally important, and we need to value both at same level and make conscious efforts to swap people by giving equal opportunity to both to be associated with both jobs alternatively with proper training.

We keep upgrading our systems; we upgrade the operator stations, the processors of DCS & PLC, the UPS etc. It is very rare we upgrade our control valves or transmitters. Though we do planned upgrades of electronic pressure & DP transmitters, pneumatic level transmitters with new technologies, it is not to the extent we upgrade our control systems. More so, we mostly do not upgrade control valves, which ultimately control the process. So these field items of older technologies are to be maintained to the best condition to achieve total plant performance and profitability.

Recollecting from February InTech "Talk to Me": "Having everyone working on the same page, and knowing what to do and when to do it, is key for a team to succeed."

S.K. Bhattacharjee, Chambal Fertilisers & Chemicals Ltd

Trading with China

I read the article "China's predatory trade practices" in the March InTech, and I was hoping you could help me with a question.

I was taught the trade deficit is a figment of the media's imagination. The books are ALWAYS balanced.
When we buy a Chinese product, our cash account decreases by the price of the product, but our goods account increases by that same amount.

China gets a piece of green paper (U.S. Dollars), and we get a power drill.

It can be argued we are better off with the machines and durable products than they are with U.S. dollars.
Where am I going wrong?

Ed Shuler


I don't think the trade deficit is a figment of an imagination, whether it is the media or government or anybody else. But I can certainly see your point regarding bookkeeping. That point is not wrong. The "trade deficit," the term has a definition though, and I'm sure you are aware of what it is.

Interpreting the whole mess is where your valid point of "we got a drill and they got a piece of paper" comes in.

This article, however, is talking about the "predatory" angle. That is where the Chinese use "coerced" labor to produce a product that others who have fair labor practices in place cannot afford. They compound that by having an underpriced currency that the government also controls, which makes the price of the drill even cheaper. They then, effectively, put all the other drill manufacturers out of business, which gives them market share and the power to charge what they want.

That is predatory.

It is a similar strategy to dumping, which is when a product goes to a market for less than the cost to produce that product, so as to put less able companies out of business, so the dumping companies (countries) can get market share.

Here is a definition of trade deficit (surplus) we can work with: The balance of trade (or net exports, sometimes symbolized as NX) is the difference between the monetary value of exports and imports in an economy over a certain period of time. A positive balance of trade is known as a trade surplus and consists of exporting more than is imported; a negative balance of trade is known as a trade deficit or, informally, a trade gap.

The interpretation of the number is the big deal … good, bad, whatever. As an entity in itself, it is merely bookkeeping. 

Nicholas Sheble, InTech Senior Technical Editor