Rosemount 644 Head-Mount Temperature Transmitter

The Rosemount 644 Head-Mount Temperature Transmitter is Emerson's most widely deployed compact temperature transmitter in Saudi Arabia's petrochemical, power generation, and water treatment industries. Rated for -40°C to +85°C ambient temperature and featuring a DIN B compact form factor, the 644 fits the thermowell head connections at Saudi Aramco's standard 316L SS NPT and flanged thermowell installations specified in SAES-I-012. The transmitter's universal input accepts all thermocouple types and RTDs, allowing Saudi Aramco instrument procurement teams to standardize on a single transmitter part number while supporting multiple sensor types across diverse process units.

The 644's HART 5/7 communication with multivariable capability transmits process temperature, cold junction temperature, and sensor resistance data from a single 4-20mA loop, enabling Saudi Aramco's AMS (Asset Management Suite) to track sensor health trends over time without additional wiring. The transmitter's lead resistance compensation up to 100 ohm eliminates measurement error from the long thermowell extension and cable runs common at Saudi Aramco's tall distillation columns and pipeline ROW installations. Automatic cold junction compensation maintains thermocouple measurement accuracy through the extreme Saudi ambient temperature swings between winter and summer operation.

With 20 year mean time between failure (MTBF) calculated by Emerson's reliability engineering team, the 644 minimizes instrument maintenance workload at Saudi Aramco's high-availability facilities where unplanned work orders are tracked against HSE KPIs. The transmitter's plastic IP68 head-mount housing protects electronics during the periodic water-jet cleaning of process areas at SABIC's plastic and chemical facilities in Jubail. Gold-plated terminal blocks prevent oxidation of electrical connections in the salt-laden atmosphere at SWCC desalination plants along the Red Sea coast.

Razz Middle East provides 644 transmitters in both standard and SIL 2 versions to support Saudi Aramco's safety instrumented system standardization efforts. Our instrument specialists assist Saudi Aramco project engineers with tag number programming, engineering unit selection, and sensor type verification to ensure correct transmitter configuration before delivery to site.