Endress+Hauser Cerabar S PMP75 Absolute Pressure Transmitter — Flanged Diaphragm Seal, 0…2 bar abs, PROFIBUS PA

The Endress+Hauser Cerabar S PMP75 combines a metallic piezoresistive sensor with an oil-filled flanged diaphragm seal. That combination exists for one reason: to keep the process medium away from the sensor itself — hot, viscous, corrosive or crystallising media. The unit offered here is calibrated to 0…2 bar absolute and communicates digitally over PROFIBUS PA. Every photograph in this gallery was taken of this exact device at the seller's premises, and its nameplate — range, protocol and ingress protection — is legible in those images.

One thing to understand before ordering: this is an absolute sensor, not gauge. An absolute cell is referenced to sealed vacuum and will read roughly 1 bar at atmospheric pressure, not zero — the classic commissioning surprise. In exchange, barometric variation is seen rather than cancelled, which is exactly what you want for vacuum service, condensers, distillation columns, and any point where atmospheric swing must not enter the measurement. The ordered range is the cell's full nominal span, i.e. a 1:1 turn down — the accuracy-optimal way to use it.

On accuracy, honestly: the reference accuracy of the 2 bar cell per the official TI00383P datasheet is ±0.075 % of set span (turn down up to 5:1). But Endress+Hauser states twice in that same document that diaphragm-seal errors are not included in these figures and are calculated separately. The real installed accuracy of a diaphragm-seal assembly depends on membrane diameter, fill fluid, capillary length and bore, and the temperature difference between process and ambient. Long-term stability is likewise called out separately for this 2 bar cell and is worse than the rest of the range: about ±0.07 % of URL per year. Any copy presenting ±0.075 % as the finished accuracy of a diaphragm-seal instrument is misleading — and E+H does not make that claim.

Communication is PROFIBUS PA Profile 3.0: a single pair carries both power and data (9…32 V DC from the bus, 13 mA draw), with no separate supply and no analogue input card. But it also means you cannot simply wire this into a PLC. PA runs at 31.25 kbit/s and needs a DP/PA segment coupler or link plus bus terminators at both ends of the segment. If that infrastructure does not already exist on site, the 4–20 mA HART version is the cheaper and more sensible order. The upside of digital output is that the electronics error term drops to 0 %, against 0.05 % for the analogue output.

Points to settle before ordering

• This is the general-purpose version carrying the CE mark, with no Ex marking on the plate — it is not suitable for classified hazardous areas.
• SIL certification is not available on this version. The Endress+Hauser functional safety manual states plainly that the safety-related signal is the 4–20 mA analogue output and that all safety functions refer solely to that output; the PROFIBUS PA variant is not covered by it at all. If you need SIL, order the HART version.
• In vacuum service the silicone fill-fluid ceiling drops from 250 °C to 180 °C — not academic on a low-range absolute point. E+H recommends mounting the transmitter below the diaphragm seal for vacuum duty.
• Flange size and rating, membrane material and fill fluid are not specified in the available information, and each affects price and temperature limits. Confirm these with the seller before finalising the order.

This product is offered on Kurdoff by the Barmaan store — a supplier of industrial instrumentation — to buyers in Kurdistan and Iran. Pricing is on request: use the contact button for current price, availability and delivery terms directly from the seller.