Honeywell SmartLine STA800 Absolute Pressure Transmitter

STA800 SmartLine absolute pressure transmitter

The Honeywell SmartLine STA800 is a smart absolute pressure transmitter that measures process pressure against a vacuum reference, using a piezoresistive silicon sensor with on-chip temperature compensation. It belongs to the ST 800 SmartLine family, and the same specification also covers the lighter STA80L in-line versions. Seven Star LLC supplies the STA800 in Oman and the GCC as an independent supplier in Muscat; this page sets out the ranges, outputs, materials and options so an enquiry can be specified correctly.

Absolute measurement matters where atmospheric pressure changes would corrupt a gauge reading: vacuum service, evaporators, distillation columns, condensers, compressor suction and barometric compensation. The STA800 is built for that duty, with ranges from deep vacuum up to 3,000 psia.

STA800 models and measuring ranges

The STA800 series is split by range code. Honeywell lists the dual-head STA822 and STA840, and the in-line STA82L, STA84L and STA87L, as follows.

Zero and span may be set anywhere inside the lower and upper range limits, and the lower range limit for all models is absolute zero.

STA800 technical specifications

How the STA800 works and what it reports

The process pressure deflects a barrier diaphragm, and the fill fluid passes that movement to the silicon sensor. Because the STA800 is absolute, one side of the sensor is referenced to vacuum. Temperature is measured at the sensor and each meter body is individually characterised at the factory, so electronics modules can be swapped without losing the in-tolerance performance.

Standard diagnostics are divided into critical items (electronics fault, meter body memory corruption, configuration data corruption, sensor communication timeout) and non-critical items (display failure, sensor over temperature, PV out of range, tamper attempt alarm). HART and Fieldbus versions support NAMUR NE-107 extended diagnostics. An optional plugged impulse line detection feature signals a blocked process connection, and an optional dual or triple calibration stores up to three customer ranges in the meter body.

STA800 selection and ordering checklist

• Range code: STA822, STA840, STA82L, STA84L or STA87L, chosen so that the maximum pressure sits below the MAWP and the calibrated span is not too deep into the turndown limit.
• Construction: dual-head STA800 or in-line STA80L, which are different bodies with different process connections.
• Wetted materials: diaphragm and process head, from 316L stainless steel to Hastelloy C-276, Monel 400 or tantalum; carbon steel heads are not recommended for water service.
• Fill fluid: Silicone 704 has a minimum rating of 0 °C, while CTFE is rated down to −40 °C.
• Protocol: HART, DE or FOUNDATION Fieldbus.
• Display: none, standard LCD or advanced graphic display, with or without zero and span buttons.
• Approvals: FM, CSA, ATEX, IECEx and several regional approvals are offered; state the one your site needs.
• Options: lightning protection, NACE materials, plugged line detection, dual or triple calibration, SIL certification.

STA800 approvals and safety data

The datasheet lists explosionproof, intrinsically safe and non-incendive approvals for FM, CSA, ATEX and IECEx, together with others such as INMETRO, NEPSI, KOSHA and EAC. Enclosure rating is Type 4X, IP66 and IP67. ST 800 products carry IEC 61508 SIL 2 certification for single use and SIL 3 for redundant use, assessed by Exida and TÜV Nord. A marine certificate set covers ABS, BV, DNV, KR and LR for the ST 800 family when the marine option is ordered. Match the approval code on the label to your plant documentation, because approvals depend on the exact order code and not on the base model alone.

STA800 installation, commissioning and maintenance

Mount the transmitter on its bracket, keep impulse tubing short and well sealed, and verify there are no leaks before zeroing. Since absolute pressure has no vented reference, always zero against a known vacuum or a calibrated reference rather than against atmosphere. Honeywell recommends calibration verification every four years as a typical interval.

The modular design allows meter bodies, electronics, indicators and lightning protection to be exchanged. In most electrical environments the electronics and display can be changed in the field without breaking approvals, with the exception of flameproof installations. Keep a spare electronics module and display on the shelf to cut downtime.

Typical applications of the STA800 in Oman and the GCC

Regional users specify the STA800 for vacuum distillation and flash drums at refineries, condenser and ejector vacuum on power plant turbines, multi-stage flash and MED desalination evaporators, compressor suction in gas plants and absolute reference pressure in custody and gas-flow computation. High ambient heat is covered by the −40 to 85 °C rating, but mount the unit out of direct sun where possible and use sealed cable glands against dust.

STA800 information to send with an RFQ

• Model code (STA822, STA840, STA82L, STA84L or STA87L) and calibrated range
• Process fluid, pressure and temperature, including vacuum conditions
• Wetted material and fill fluid
• Output protocol, display and approval
• Special options such as lightning protection, NACE, SIL or marine certificates
• Quantity and delivery location

Documents and quotation

A Honeywell STA800 technical specification (34-ST-03-85) is attached on this page. It includes the full model selection tables, so you can build the order code against it.

Send the STA800 model code or the application details, and we will prepare a quotation for Oman and the GCC.