SOR 815DT Smart Differential Pressure Transmitter

A compact differential pressure transmitter with HART, Modbus and a built-in switch

The SOR 815DT is a smart differential pressure transmitter for hazardous locations and hostile environments. SOR positions it for jobs where a traditional DP transmitter would be too bulky or too expensive: filter differential, distillation column pressure drop, compressor skids, and as a lower-cost alternative for level and flow measurement. The housing is 316 stainless steel and explosion proof, and the face-to-face dimension is only 55.9 mm (2.2 in).

One device gives several outputs. The continuous 4 to 20 mA signal carries the HART 7 protocol, a low-power 1-5 VDC mode is available, and RS-485 Modbus RTU is built in. A configurable normally-open solid-state switch (SPST) is included, so the same unit can trigger a high-differential alarm without a separate pressure switch.

Technical specifications

Choosing the range, output and switch mode

Pick the span from the real differential, not the line pressure. The static-pressure limit is a separate figure: the unit must not see more than 1,000 psi at either port, and the HI-LO differential must stay within three times the selected full-scale range. Because turndown is only 5 to 1, order the range close to the working differential rather than relying on large re-ranging.

For switch duty, SOR lists nine configurations. Mode 3, a window that closes the switch while pressure sits inside a chosen band, is the factory default; single-point, dead-band and PWM modes are alternatives, and the specific action can be requested at order. If power is lost the contacts open. A filter alarm, for example, would normally use a single-point or dead-band mode.

Installation and what to confirm before ordering

Both process ports are 1/4 in NPT(F), stamped H and L; the Lo side may be vented to atmosphere. Use two wrenches when connecting, and install by trained personnel only. The instrument has no user-serviceable parts and flamepath joints are not intended to be repaired, so a failed unit goes back to the manufacturer. For dual-seal versions, orient the nameplate and set screw as shown in the instruction manual to keep the IP and NEMA ratings.

Confirm before ordering: the required psid range, 4 to 20 mA/HART or low-power 1-5 VDC, whether the switch is needed and in which mode, wetted-material suitability for the process fluid, and the area classification certificate you need. The ATEX and IECEx marking above is taken from the manufacturer declaration for the 800 Series, so ask for the certificate that matches the exact model code.

Documents and quotation

The attached SOR product bulletin (Form 1609) summarises features and ranges, and the instruction manual (Form 1588) covers wiring, switch modes, HART commands, Modbus mapping and dimensions. For a quotation send the range, output, switch mode, connection and certificate requirement. See other pressure instrumentation products.