The expression “You get what you paid for” definitely applies to instrumentation. Automation is expensive, but the payback is there when it is executed correctly. Unfortunately, many engineers try to save a couple of bucks and go with the untested “bargain brand” and often pay a wicked price for it. Some instruments are cheap for a reason.
Concept: Short term, penny-pinching instrumentation purchasing decisions may cost a plant thousands (or even millions) of dollars over the life of a control system. Spend the extra money and buy a brand that the plant knows and trusts.
Details: Automation engineers are under a lot of pressure to keep the price down, or they are asked to do a project for significantly less money than was estimated. (How many times has an engineer been asked, “I know the project was estimated at $yyyy, but what can you do for $xxxx?”) In such cases, resist the urge to go with cheaper instrumentation and instead cut the overall scope to make up the budget difference. You can always find an alternate brand of instrument that is being offered at a significant discount and is marketed as being “just as good as Brand X.” Unfortunately, the ultimate price that the plant often pays fighting through start-up, struggling to get technical support, and ultimately replacing the unit will be significantly higher than what would have been paid if the higher quality instrument had been purchased at the start.
Please note that this tip is NOT suggesting that cheaper equipment does not deserve a chance. Sometimes a vendor discovers a better technology or a cheaper method of manufacturing that DOES produce an instrument that is lower in cost and is just as good or better. In such a case, purchase a single unit and trial it in a less critical area of the plant. Buying 200 of the untested units for a large project is just asking for trouble.
Watch-Outs: Be sure you have investigated and confirmed there is a significant design, application, performance, and maintenance advantage before going to sole sourcing. Also consider the synergy and free time for creativity from standardization afforded by sole sourcing.
Exceptions: Some instrument brands stand so far above the others that it simply is not worth investigating another vendor. In such a case, bidding alternates is probably a wasted effort unless the alternate offerings improve dramatically or the sole source vendor starts raising their pricing significantly.
Insight: Buying high-quality instrumentation does NOT mean that the buyer has to get fleeced and pay list price. Always have at least two major vendors qualified for each type and brand of instrumentation. The competition keeps both of them honest, and a plant can often achieve some good discounting if they are a consistent customer.
Rule of Thumb: Do not skimp on instrumentation. Buy good quality equipment and it will last for years. To keep the price down, always have two qualified vendors.