As part of our continuous product portfolio upgrade, our company will gradually transition its Endress+Hauser (E+H) stock models from the 55B and 51B series to the new 50 series, with the 50T range becoming our standard stocked offering. This is not a simple model replacement: the 50T series delivers measurable gains in measuring accuracy, structural reliability, field adjustment convenience, surge protection and cost efficiency — while the instrument itself becomes more compact and easier to install.
For customers currently running 55B or 51B transmitters, the transition brings a clear performance step-up at a more competitive price point. Below is a complete comparison of what has changed.
| Feature | 55B / 51B Series | 50T Series |
|---|---|---|
| Measuring accuracy | 0.075% | 0.065% |
| Chamber structure | Single chamber | Dual chamber |
| Zero & span adjustment | Not available on the housing | Dedicated zero and span push buttons |
| Lightning protection | Not available | Optional lightning protection |
| Price | Baseline | More competitive |
| Instrument size | Larger footprint | More compact housing |
| Nameplate | Plastic | Stainless steel |
The reference accuracy improves from 0.075% to 0.065% of span. In practical terms, on a typical level or differential pressure measurement loop this means a tighter error band, better repeatability and more reliable inventory or process readings — a real advantage in custody transfer, tank gauging and quality-critical production where small deviations translate into material losses or batch rework.
The 51B and 55B use a single-chamber housing, while the 50T series moves to a dual-chamber structure that separates the terminal compartment from the electronics compartment. This physical separation protects the electronics from moisture, dust and accidental contact during wiring and maintenance, and it allows field wiring to be carried out without opening the electronics side. The result is fewer environmental failures and faster, safer commissioning and service work.
The 50T series adds dedicated zero and span adjustment buttons on the housing. Technicians can trim the lower and upper range values directly at the device without a handheld terminal or laptop, which shortens commissioning time and reduces the need for specialist tools during routine calibration.
A built-in lightning protection option is now available on the 50T series. For installations in open plants, on tank farms, on elevated structures or in regions with frequent thunderstorms, this integrated surge protection significantly reduces the risk of transmitter damage from induced voltage spikes — without the cost and cabinet space of external surge arresters.
Alongside the performance improvements, the 50T series is offered at a more attractive price than the outgoing 55B and 51B models. Customers therefore gain higher accuracy, a dual-chamber housing, field adjustment buttons and optional surge protection at a lower cost of ownership.
The housing of the 50T series is noticeably smaller and lighter than that of the 55B and 51B. This simplifies installation in crowded skids, compact manifolds and retrofits where space is limited, and it reduces shipping weight for export orders.
The nameplate has been changed from plastic to stainless steel. The stainless steel plate resists UV degradation, corrosion, abrasion and chemical washdown, so model, range and certification data remain legible for the full service life of the instrument — an important detail for plants with outdoor installations and strict traceability requirements.
The switch from 55B and 51B to the 50 series will be carried out progressively as existing stock is consumed. To make your planning straightforward, please note the following:
Our technical team is available to review your current 55B and 51B measuring points and recommend the matching 50T configuration, including the lightning protection option where local conditions call for it. Please contact us with your tag list and process parameters to receive a tailored upgrade proposal and updated quotation.
