Weschler H6856 Replaced by PNP Technology

Obsolete analog meters, or refurbished units still on the market and in many instrumentation and control rooms (I&C), have long posed a tedious challenge to operators looking to replace them. Often the arduousness of finding suitable replacements can also accrue higher expenses as newer technology demands higher operating costs. However, the most common problem operators and engineers face when trying to replace obsolete instrumentation is matching dimensions and specifications. A newer digital unit might perform the functions of your old analog meter, it might offer a brighter display or bar graph reading, but does it match your panel space? Can it fit inside the panel cutout without necessitating changes to surrounding wiring or the panel itself? The inverse is also true—dimensions may align, but functions/specifications are not met. Additionally, in certain industries like the nuclear sector, most instruments in the control room need to be backed up by a spare unit, should the functioning meter fail.

All of this can lead to an exhaustive and cost prohibitive search for the proper replacement. Is there an easier way? The industry has evolved to the point where plug and play technology can not only solve the analog/digital replacement challenge, but eliminate the need for overloaded spare inventory as well. Otek’s latest contribution to this effort is our Plug & Play (PNP) series of digital instrumentation.

For example, Weschler offers its edgewise analog H6286 to replace the obsolete Yokogawa 286. Weschler’s H6286 are 1 to 1 ½ inches, which makes finding a digital replacement that small very difficult in today’s market. With the PNP series, finding a replacement can be as simple as selecting a 1 ½ housing, an adapter plate if required, and plugging the PNP meter into the surrounding panel. How can it be that simple?

PNP technology is designed to replace meters ranging from 1½” to any size or shape of meter in the I&C room and simulator. It accomplishes this by using the universal input assembly, the Hub, that accepts any signal or power offered, by just selecting signal conditioners (up to four per I/O module) that cover over 50 input signals and either 100% signal power like analog meters (such as current loops [4-20 & 10-50 mA], VAC to 260V, VDC to 300V, AC Amps to 5Amps (AC & DC, Watts & Hertz). For units requiring external power (such as RTD, TD, S-G, pH, ORP, etc.) or even 4-20mA retransmission, PNP technology uses universal power modules that are plugged, inside the hub, into the instrument, requiring no solder or otherwise alteration to the surrounding wiring and panel displays that might void certification.

General specifications include a 4½ digit display, ± 0.5% accuracy of the full scale ±1 LSD, temperature coefficient: ± 50 PPM/°C, an operating temp of -20 to +70°C, CMRR: >90dB@ 50-60Hz, humidity levels of 5-95% (non-condensing), front panel options for NEMA 3 or NEMA 4X, EMI/RFI Class1E adherence, power requirements for loop powered options at >10<100mW and external requirements at >50<200mW, with a conversion rate of 3 seconds, and recalibration suggested every 2 years. Additionally, PNP metering technology can be applied to mil-spec and Class 1E applications, as the construction of the instruments would be designed to be obsolescence-hardened and sourced from universal components, often exceeding the 40-year parts availability required by the military and nuclear industries.

Replacing obsolete technology like Weschler’s H6286 does not have to be as complicated and expensive as it once was. With Otek’s PNP technology, the replacement process as well as spare inventory can be streamlined in an effective, efficient, and forward-thinking manner. Look for the PNP to hit the market in the summer of 2021.

For more information on the PNP or other replacement instrumentation, please call (520) 748-7900 or email sales@otekcorp.com