Issues in selecting instrument manufacturers

This generally falls under procurement considerations; the designers only need to prepare a quotation request (including specifications, data sheets, and purchase orders). Of course, when making a choice, designers definitely need to refer to certain manufacturers. But as the original poster mentioned, these two procurement methods are decided by the purchasing staff, and each has its advantages and disadvantages. Buying from the same supplier doesn’t necessarily mean it’s worse than buying from multiple suppliers. For some common products (such as pressure and temperature transmitter), the level of detail in their classification is too high, which is troublesome and doesn’t help to reduce prices; moreover, after-sales service becomes complicated as well. It also depends on the size of your contract; the methods vary. Moreover, for larger projects, tenders are usually required for procurement; even if it’s with the same company, one still has to compare E+H against ROSEMOUNT... Last edited by emir001 on 2007-12-28 16:34]

I think it would be best to use the same company, but that’s not possible, because the owners wouldn’t do that – they want as many people as possible to have the opportunity to make money!

So, it seems that the communication protocol of the entire DCS is more compatible with other protocols; ROSEMOUNT’s HART protocol is quite good

So, it seems that the communication protocol of the entire DCS is more compatible with other protocols; ROSEMOUNT’s HART protocol is quite good

I select the flagship products of each company; it’s not possible to choose just one. Among instruments, Emerson is a pioneer, but its products aren’t perfect in every aspect. For pressure and temperature measurements, I use Emerson’s products, while for mass flow meters and analyzers, I opt for E+H’s ones. As for valves, I generally go with those from Emerson. These are my selection principles for projects.

The key lies in the compatibility of your control system and the design requirements of the process; these are the basic principles for selecting instruments

I agree with the view from the 6th floor: nowadays, each manufacturer’s products excel in just one particular aspect; they offer good value for money. There is no manufacturer that can cover everything, and the instruments produced by different companies are becoming increasingly homogeneous. Therefore, by specifying the required criteria and various general requirements, it’s possible to select a few good products (at least two), and then compare their value for money!

I agree with what was said on the 3rd floor; actually, as a maintainer, it’s best to use the same brand, as that makes maintenance easier. But that’s impossible; I’m working on a large project, and when it comes to making choices, you and I can only serve as a reference – the final decision is made by those in higher positions, who take into account more factors than you and I. Those so-called bids from several companies are just a formality. The truth.

Selection is a meticulous task; the chosen products should be representative, not only in terms of functionality but also in terms of their applications. Software for calculating parameters such as control valves is quite representative in Wuzhong ； The selected product must be approved by the customer; otherwise, the product selection is merely based on functional capabilities.

So, it seems that the communication protocol of the entire DCS is more compatible with other protocols; ROSEMOUNT’s HART protocol is quite good

I don’t agree with using products from the same manufacturer for multiple types of instruments. Moreover, a single project often involves many different kinds of instruments, and it’s absolutely impossible for one manufacturer to have products covering all of them. Even if a certain instrument manufacturer produces a wide range of products, each manufacturer has its own flagship products; it’s not possible for every type of instrument to be a flagship product. Therefore, using products from just one manufacturer is simply not practical! The best way to manage this is to use instruments from the same manufacturer for each type; for example, use EJA for transmitters, Wu Zhong products for control valves, and instruments from one particular manufacturer for field pressure gauges. I think this is a good approach

It’s helpful. Our project has just started, and I am comparing instruments from several manufacturers

I think it’s better to stay separate; after all, every company has its own strengths as well as weaknesses!

As long as it’s cheap and meets the requirements, that’s fine; if it costs too much, the boss will be unhappy.