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Brand: SOR
SOR 1800DP Differential Pressure Transmitter
Description
A conventional DP transmitter for flow, level and filter monitoring
The SOR 1800DP is the differential pressure version of the SOR 1800 Series conventional transmitters. SOR describes the series as a rugged solution for pressure, level and flow applications and as a drop-in replacement for legacy transmitters. The 1800DP has a double-flange body with 1/4 in NPT(F) process connections and drain valves, an aluminium explosion-proof housing and a 4-20 mA output with optional HART 5, 1-5 VDC low power or Modbus.
Typical duties are the differential across an orifice plate or venturi for flow, hydrostatic level in a closed vessel using both ports, and pressure drop across filters or strainers.
Technical specifications
| Parameter | Specification |
|---|---|
| Manufacturer / series | SOR Inc. (SOR Controls Group), 1800 Series |
| Model | 1800DP differential pressure transmitter |
| Output | 4-20 mA, linear (default) or square root; 1-5 VDC low power; HART 5 (optional); Modbus; Modbus with 4-20 mA |
| Accuracy (linearity, hysteresis, repeatability) | Turndown up to 10:1: plus/minus 0.075% URL; 10:1 to 100:1: plus/minus (0.0075 x TD)% URL; square-root output 1.5 x linear |
| Long-term stability | Up to plus/minus 0.2% URL per 5 years |
| Response time / damping | 200 ms max. / 0 to 100 s configurable |
| Supply voltage | 4-20 mA: 10.5-55 VDC; HART with 250 ohm: 16.5-55 VDC; 1-5 VDC low power: 9-32 VDC; Modbus: 5-32 VDC |
| Power consumption | 500 mW max. at 24 VDC, 20.8 mA |
| Range 006 | -0.87 to 0.87 psid; min. span 0.03 psid; max. turndown 30:1; max. static pressure 3,626 psi (25 MPa) |
| Range 040 | -5.8 to 5.8 psid; min. span 0.06 psid; 100:1; 5,801 psi (40 MPa) |
| Range 250 | -36.3 to 36.3 psid; min. span 0.36 psid; 100:1; 5,801 psi |
| Range 01K | -72.5 to 145 psid; min. span 1.45 psid; 100:1; 5,801 psi |
| Range 03K | -72.5 to 435 psid; min. span 4.35 psid; 100:1; 5,801 psi |
| Range 10K | -72.5 to 1,450 psid; min. span 14.5 psid; 100:1; 5,801 psi |
| Over pressure, each side | 2,321 psid (16 MPa) |
| Process connection | 316SS 1/4 in NPT(F), two flanges, drain valve on end, upper face or lower face (C1E, C1U, C1L) |
| Diaphragm / fill fluid | Stainless steel or Hastelloy / silicone oil or fluorocarbon oil |
| Process temperature | Silicone oil -40 to 248 F; fluorocarbon oil -40 to 185 F; flameproof limits to 176 F |
| Ambient temperature | -40 to 185 F without approvals or display; -4 to 158 F with LCD; intrinsically safe -40 to 140 F; flameproof -13 to 140 F |
| Housing / IP rating | Aluminium explosion-proof housing / IP67 |
| Weight (no adapters or brackets) | 8.82 lb |
| Manufacturer warranty | 3 years |
| Agency options (catalog) | ATEX/IECEx Ex db IIC T6 Gb, Ex tb IIIC T80 C Db; ATEX/IECEx Ex ia IIC T4 Ga; CSA Class I, II, III Div. 1; CE |
Reading the model code
SOR uses a quick-select tree: model (1800DP), range code (006, 040, 250, 01K, 03K, 10K), diaphragm material (S stainless steel or H Hastelloy), fill fluid (S silicone or F fluorocarbon), conduit connection (W1, F1 or F2 adapter), output (C 4-20 mA, V 1-5 VDC, Z 4-20 mA with HART 5, M Modbus, D Modbus with 4-20 mA), display (00 or IN LCD), process connection (C1E, C1U, C1L) and accessories. The catalog example is 1800DP-250-S-S-F1-Z-IN-C1E-CS.
Selecting range and options
Choose the range so that the lower and upper measuring points both sit within the range limits and the span is not below the smallest possible span. Accuracy degrades with turndown above 10:1, so pick the tightest range that still covers the maximum differential. Note the temperature limits: the flameproof approval limits the maximum process temperature to 176 F, while the intrinsically safe version limits it to 248 F. Wetted parts can be ordered with NACE MR0175/ISO 15156 compliance, degreasing or electropolishing as listed accessories.
Confirm before ordering: differential range and static pressure, diaphragm and fill fluid for the process, output and protocol, display, conduit adapter, hazardous-area approval, and mounting bracket. Remote and direct-mount diaphragm seal versions (1800RM, 1800DM) are separate models in the same catalog.
How the SOR 1800DP works
The two process ports apply the high and low side pressures to the sensor. The sensor responds to the difference between them, and the electronics turn it into a 4-20 mA output. The double-flange body lets both sides connect through 1/4 in NPT process connections with drain valves.
Where the 1800DP is used
- Flow across an orifice plate
- Flow across a venturi
- Hydrostatic level in closed vessels
- Pressure drop across filters
- Pressure drop across strainers
Selection checklist for the 1800DP
- Differential pressure range
- Static pressure
- Output type
- Diaphragm material
- Fill fluid
- Process temperature
- Supply voltage
- Process connection layout
Installation, commissioning and maintenance notes for the 1800DP
Mount the transmitter so the impulse lines are short and free of trapped gas or liquid. Open the drain valves to vent the body if needed. Check the zero with both sides at the same pressure and set the range before service.
Requesting a quotation for the SOR 1800DP
Please send the differential range, the static pressure, the fluid and the output needed. Seven Star LLC serves industrial customers in Oman and the GCC and replies with a quotation based on the information provided.
1800DP series
It belongs to the SOR 1800 Series of conventional transmitters.
1800DP transmitter type
It is the differential pressure version of the series.
1800DP duties
SOR describes the series as a rugged solution for pressure, level and flow.
1800DP body
It has a double-flange body.
1800DP process connections
The connections are 1/4 in NPT(F) with drain valves.
1800DP housing
The housing is aluminium and explosion-proof.
1800DP output
The standard output is 4-20 mA, linear by default or square root.
1800DP output options
Options are HART 5, 1-5 VDC low power and Modbus.
1800DP response time
The response time is 200 ms maximum.
1800DP damping
Damping is configurable from 0 to 100 s.
1800DP supply voltage
The 4-20 mA supply is 10.5 to 55 VDC.
1800DP HART supply
With HART and a 250 ohm load the supply is 16.5 to 55 VDC.
1800DP low power supply
The 1-5 VDC low power version uses 9 to 32 VDC.
1800DP Modbus supply
The Modbus version uses 5 to 32 VDC.
1800DP power consumption
The power consumption is 500 mW maximum at 24 VDC.
1800DP range 006
Range 006 is minus 0.87 to 0.87 psid with a minimum span of 0.03 psid.
1800DP range 040
Range 040 is minus 5.8 to 5.8 psid with a minimum span of 0.06 psid.
1800DP range 250
Range 250 is minus 36.3 to 36.3 psid with a minimum span of 0.36 psid.
1800DP range 01K
Range 01K is minus 72.5 to 145 psid with a minimum span of 1.45 psid.
1800DP range 03K
Range 03K is minus 72.5 to 435 psid with a minimum span of 4.35 psid.
1800DP range 10K
Range 10K is minus 72.5 to 1,450 psid with a minimum span of 14.5 psid.
1800DP over pressure
The over pressure limit is 2,321 psid on each side.
1800DP diaphragm and fill
The diaphragm is stainless steel or Hastelloy, and the fill is silicone oil or fluorocarbon oil.
1800DP process temperature
Silicone oil works from minus 40 to 248 degrees F, and fluorocarbon oil from minus 40 to 185 degrees F.
Transmitter records for the 1800DP
Record the range, the calibration date and the installed location.
Choosing the right 1800DP range
Choose the range from the expected differential and the static pressure of the line.
Documents and quotation
The attached documents are the SOR 1800 Series pressure transmitter catalog (Form 1906, includes the 1800DP specification, ordering tree, ranges and dimensions) and the 1800 Series product bulletin (Form 1891). Send the full model code or the process data for a quotation. See other pressure instrumentation products.
Datasheets & Documents
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About brand
SOR is an American maker of pressure, temperature and level instruments, based in Lenexa, Kansas. Roy Dunlap started the business in 1946 as a machine shop, and in 1956 developed a pressure switch with a static O-ring seal, which gave the company its later names, Static O Ring (1965) and SOR (1978). SOR has supplied nuclear-qualified switches since 1982, and in September 2026 DwyerOmega announced it had acquired SOR Controls Group.
Seven Star LLC is an independent supplier in Muscat. We list SOR switches and transmitters for oil and gas and process plants in Oman and the GCC.
SOR company profile
| Founded | 1946, Kansas, USA, by Roy Dunlap |
|---|---|
| Headquarters | Lenexa, Kansas |
| Key invention | Pressure switch with a static O-ring seal, 1956 |
| Name | Static O Ring (1965), SOR (1978) |
| Ownership | DwyerOmega, acquisition announced 24 September 2026 |
| Product families | Pressure, differential pressure and temperature switches, 1500 series level switches, magnetic level indicators, SSi temperature sensors, SENSOR sampling systems, nuclear-qualified switches |
Milestones
- 1946: Roy Dunlap starts the business.
- 1956: The static O-ring pressure switch is developed.
- 1978: The company becomes SOR.
- 1982: SOR begins its nuclear-qualified switch programme.
- 2026: DwyerOmega announces the acquisition of SOR Controls Group.
SOR product series
Switches include the 6L explosion-proof pressure switch, the 1510 side mounted float level switch, the 2700 ultrasonic point level switch and the 1520 top mounted vane flow switch.
Transmitters include the 815DT smart differential pressure transmitter and the 1800DP differential pressure transmitter.
Mechanical switches such as the 6L give a direct trip signal without a power supply, while transmitters send a continuous 4-20 mA signal. Explosion-proof enclosures and stainless wetted parts are standard on many models for oil and gas service.
Where SOR instruments are used
Pressure alarms and trips, high and low level alarms on vessels, flow proving and differential pressure measurement in wellsites, gas plants and refineries.
SOR products we list
Ordering SOR instruments: what we need
Send the model code, range or setpoint, wetted materials, process and electrical connection and the hazardous-area certification.
Facts checked against SOR company history and DwyerOmega's September 2026 announcement, October 2026.
Browse SOR products by category: Pressure Instrumentation, Flow Indicators & Switches, Level Instrumentation.
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Frequently Asked Questions
Up to 10:1 turndown the catalog gives plus/minus 0.075% of URL; above 10:1 the figure is plus/minus (0.0075 x turndown)% of URL.
4-20 mA (linear or square root), 4-20 mA with HART 5, 1-5 VDC low power, Modbus, or Modbus with 4-20 mA.
006, 040, 250, 01K, 03K and 10K, from plus/minus 0.87 psid up to an upper range limit of 1,450 psid.
3,626 psi (25 MPa) for range 006 and 5,801 psi (40 MPa) for the other ranges, with 2,321 psid overpressure on each side.
The catalog lists ATEX/IECEx Ex db IIC T6 Gb, ATEX/IECEx Ex ia IIC T4 Ga and CSA explosion proof Class I, II, III Div. 1 as options.

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