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Brand: Watson Smith
Watson Smith Type 300D Portable Digital Pressure Meter
Description
A hand-held digital meter for calibrating pneumatic instruments
The Watson Smith Type 300D is a portable precision digital pressure meter for the calibration and test of pneumatic instruments and systems. It has automatic zero calibration for added accuracy, a back-light for easy reading and a standard set-up retention feature, so the last setting remains when it is powered up again. It is hand-held, battery operated for up to 200 hours, housed in a robust plastic case and rated IP65 when the hose is connected.
A leak test function is built in: prime the instrument with the pre-stress pressure level, start pressure, test time and allowable pressure change, and it tests for leaks over a wide range of applications. We found this datasheet only as a copy issued as Watson Smith Instrumentation literature (dated 10/06) and hosted by a UK instrument supplier; we did not find the product in current manufacturer literature, so treat it as an older, legacy line and confirm current availability, any replacement model and lead time before you rely on it.
Technical specifications
| Parameter | Specification |
|---|---|
| Function | Portable precision digital pressure meter for calibration and test |
| Part numbers | 603500D (0 to 10.00 bar); 603900D (0 to 2 bar) |
| Input pressure range | Up to 150 psig, 10 bar, 1000 kPa |
| Media | Dry, non-corrosive air or gas |
| Display | 12.7 mm (0.5 inch) custom LCD with back-light |
| Power | 2 AA batteries; approx. 200 hours; auto switch-off approx. 12 minutes |
| Accuracy | Calibration plus or minus 0.1 percent FS; hysteresis and linearity plus or minus 0.15 percent FS plus or minus 1 digit |
| Temperature coefficients | Zero and span 0.0025 percent FS per degree C maximum |
| Stability | Plus or minus 0.2 percent maximum over 6 months |
| Operating / storage temperature | Minus 10 to plus 50 degrees C; minus 20 to plus 60 degrees C |
| Case / protection | Moulded plastic, black; IP65 with hose connected |
| Dimensions / weight | 155 x 67 x 40 mm; 180 g (251 g with battery) |
| Functions | Max/min, hold, 10 pressure units, zero, range lock, smooth, leak test |
Controls and functions
Push buttons give MAX/MIN to determine maximum and minimum pressures as well as the current pressure, HOLD to freeze the reading, UNIT to choose from ten pressure units, ZERO to zero the instrument in the set reading orientation, RANGE LOCK to set the lower resolution only and SMOOTH to average measurements for a steadier reading. The 12.7 mm (0.5 inch) custom LCD shows OUT on over-range, a battery symbol appears at about 6.5 V and the meter switches itself off after about 12 minutes.
Selection and use
Two ranges are listed: 0 to 10.00 bar (part number 603500D) and 0 to 2 bar (603900D). The input range is up to 150 psig, 10 bar or 1000 kPa and the media must be dry, non-corrosive air or gas; the units are not suitable for continuous liquid exposure. The datasheet says the figures given are typical and not absolute for every unit manufactured. For traceable calibration work, confirm that the meter and its accuracy suit your procedure and check how it will be calibrated. Because this is an older datasheet, confirm availability, batteries (two AA) and any replacement model.
Documents and quotation
The datasheet is attached for download. Seven Star LLC is an independent supplier in Muscat. Send the model or order code, quantity and operating conditions and we will request a quotation; availability depends on the model. Related items: Portable Test and Measurement.
Datasheets & Documents
- Datasheet Watson Smith Type 300D portable pressure meter datasheet (10/06, controlled doc. 2006-127a) Download
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About brand
Watson Smith is a British maker of pneumatic instrumentation in Leeds, best known for its I/P converters that turn a 4-20 mA signal into a proportional air pressure for valve positioners and actuators. The business was started by John Watson and later joined by John Smith. It became part of IMI in the mid-1980s and is now Norgren's centre of excellence for instrumentation and positioning control.
Seven Star LLC is an independent supplier in Muscat. We list Watson Smith instruments for pneumatic control loops in Oman and the GCC.
Watson Smith company profile
| Origin | Leeds, England, founded by John Watson; John Smith joined in the 1950s |
|---|---|
| Site | Cross Chancellor Street, Leeds |
| Ownership | IMI, through Norgren, since the mid-1980s |
| Role in group | Norgren's centre of excellence for instrumentation and positioning control |
| Product families | Type 100X and 101X I/P converters, electronic, proportional and electro-mechanical I/P and E/P converters, Type 70 and Type 77 pneumatic transmitters, valve positioners |
Milestones
- 1950s: John Smith joins the business.
- Mid-1980s: IMI acquires Watson Smith.
Watson Smith product series
I/P converters include the 100X and 101X series, the Type 422 intrinsically safe converter with fail-freeze function and the Type 140 failsafe converter in explosion-proof and intrinsically safe versions; they turn a 4-20 mA signal into a pneumatic output for valve positioners and actuators. The Type 68 P/I transmitter and the Type 71 intrinsically safe P/I converter do the reverse, turning pneumatic pressure into 4-20 mA.
Manostat products include manually and mechanically operated precision pressure regulators and the SP2G2 remote manual and auto/manual loading stations. The Type 300D is a portable digital pressure meter and the FRI-30 an indicating air flow controller for level purge systems.
Where Watson Smith instruments are used
Pneumatic control valves and dampers driven from a DCS or PLC, bubbler level systems, instrument air regulation, test benches and older pneumatic loops in refineries, power stations and process plants.
Watson Smith products we list
Ordering Watson Smith instruments: what we need
Send the type and full code, input and output ranges, supply pressure, connection threads and hazardous-area certification. Each product page states the datasheet it is based on; where only an older datasheet exists, we ask you to confirm availability before ordering.
Facts checked against Norgren's company history and UK Companies House records, October 2026.
Browse Watson Smith products by category: Pressure Instrumentation, Regulators.
Related products
Frequently Asked Questions
What is the 300D used for?
Calibration and testing of pneumatic instruments and systems, including leak tests, with a hand-held digital readout.
Which ranges are available?
0 to 10.00 bar (603500D) and 0 to 2 bar (603900D) according to the datasheet.
How accurate is it?
Calibration plus or minus 0.1 percent of full scale and hysteresis and linearity plus or minus 0.15 percent plus one digit, quoted as typical.
What power does it use?
Two AA batteries for about 200 hours, with auto switch-off after about 12 minutes.
Can it measure liquids?
No. It is for dry, non-corrosive air or gas and is not suitable for continuous liquid exposure.
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