ASH Compatibility Issues - Tec Trek Web Site

Tip of the Week

NOW FOR THE NEWSLETTER

Compatibility Issues

Plenty enough issues, too many for one newsletter so let us begin.

A recent event from the field related to ASH controller and end devices not being of the same manufacture has prompted concern from an inspector/compliance guru as to system functionality & legality of both.

Without getting into many details, General Monitors S4000C Smart Sensor, with 4-20ma (milliamp) output, is being monitored by a Detcon CH10D Control Card. I guess most would raise concerns and being the concerning type my only question was, well does it work according your approved SAFE Chart?

Pretty much an industry standard, 4-20 ma (milliamp) is most common means of signal transmission for a scalable linear function as it relates to 0-100% LEL. So with that said the control card will interpret the signal to the appropriate LEL reading.  Is this legal, as it relates to codes and standards?

For process control we have many transmitter assemblies that monitor temperature, pressure & volume levels, manufactured by a variety of different companies that are monitored by PLC’s also manufactured by a variety of different companies, so why would ASH monitoring be any different? Truth is there is no difference. ASH to PLC is perfectly acceptable no matter the manufacture.

So what do the codes state, well not much?

•  ASH devices to be tested by a nationally recognized testing agency (FM, CSA, and others)
  

•  ASH devices shall provide % LEL reading, indicators & outputs for High, Low and Fault conditions
  

•  Have a reliable primary and secondary power supply for continuous monitoring.
  

•  Have suitable listings per Area Classification.
  

•  Be individually identifiable per location.
  

•  Provide means to safely calibrate & test.
  

If the above criteria have been met, well thats all that needs to be said. Would I prefer the end device and controller to be of the same manufacture, well sure for simplicity purposes of replacement parts, but my opinion is not relevant.

The above is acceptable for all end devices that transmit a 4-20ma, if it were an older system that provides a millivolt or frequency, and then it is another matter. Also if it is a proprietary protocol system, like a Det-tronics Eagle Quantum, then all must be compatible.

For Life Safety, Fire Detection Systems, the manufactures of the Fire Control Systems are very specific about what end devices are used with their individual control systems.  In fact so much so, that each manufacture of the FACP has publications, or device compatibility listing, of which end devices have been tested, approved, and suitable for integration to their FACP.


If you require more information regarding the terms and explanations above, contact me by email or phone for assistance.

The above information is covered in the following Tec Trek class segments: Awareness Training (FG-01A), Basic Technical Training (FG-01)

For more information regarding training schedules and course curriculum, please visit our Web Site at www.tectrek.org

or Contact Todd Olivier at (337) 298-7959.

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