pHS-4 Benchtop pH Meter

The pHS-4 benchtop pH meter is Pinji Scientific’s high-precision laboratory instrument, designed for applications where measurement accuracy is critical. With a resolution of 0.001 pH and accuracy of ±0.002 pH — five times more precise than standard benchtop models — the pHS-4 is the instrument of choice for pharmaceutical formulation, analytical chemistry and research environments that demand traceable, high-fidelity data.

Categories Benchtop pH Meters, pH Meters

Product Description

0.001 pH Resolution and ±0.002 pH Accuracy Five times more precise than standard benchtop models. Suited to pharmaceutical QC, precise buffer preparation and research applications where measurement uncertainty must be minimised.
7″ Color TFT Touchscreen with Metro Interface Large, intuitive display with single-tap access to all functions. Built-in “?” help button provides instant access to the on-screen operation manual at any time.
1–5 Point Auto-Calibration with Buffer Auto-ID Automatically recognises JJG119, DIN19266, DIN19267 and USA standard buffer sets. User-defined buffer values also supported for custom laboratory protocols.
Three-Level User Management Administrator, User and Visitor access levels with password protection. Supports regulated workflows requiring operator accountability and full audit trails.
1500-Point Data Storage and GLP Printing Store up to 1500 timestamped measurement records. Real-time and historical data printing in GLP-compliant format via USB or RS232.
Auto Temperature Compensation ATC range -5.0°C to 110.0°C with manual override. Ensures accurate readings across varying sample and ambient temperatures.

Technical Parameter

Model		pHS-4
Measuring Range	PH	(-2.000~20.000) pH
	mV	(-2000.0~+2000.0) mV
	TEMP	(-5.0~110.0) ℃
Resolution	PH	0.001 pH
	mV	0.1 mV
	TEMP	0.1 ℃
Accuracy (±)	PH	±0.002 pH
	mV	±0.02 %FS
	TEMP	±0.2 ℃
Stability		(±0.002pH±1d)/3h
Sensor (included)		E-331D + T-820D
Connector to Meter		BNC / RCA / Binding post
Display		7″ Color TFT Touchscreen
Electrode Holder		Included
TEMP Compensation		(-5.0~110.0) ℃ Auto / Manual
Calibration		1-5 point
pH Buffer
Data Storage		1500 data points
Connectors		USB / RS232
Printing		GLP standards
User Mgmt		Password protection
Dtae/Time		Yes
Prompt Tone		On/off
Power		DC: 12V
Operating TEMP		5℃~40℃
Humidity		≤80%
Dimensions (mm)		≈ 200×130×60
Weight (kg)		1

FAQ

What is the difference between pHS-3 and pHS-4?

The pHS-4 offers significantly higher measurement precision than the pHS-3. The pHS-4 provides 0.001 pH resolution and ±0.002 pH accuracy, compared to 0.01 pH resolution and ±0.01 pH accuracy on the pHS-3. Both models share the same 7-inch touchscreen, 5-point calibration, 1500-point data storage and GLP printing capabilities. Choose the pHS-4 when your application requires the highest available accuracy, such as pharmaceutical QC, precise buffer preparation or advanced research.

What pH buffer standards does the pHS-4 support?

The pHS-4 automatically identifies buffers from JJG119 (Chinese national standard), DIN19266 and DIN19267 (German/European standards) and USA standard sets. User-defined buffer values are also supported for custom calibration protocols.

Is the pHS-4 compatible with third-party pH electrodes?

Yes. The pHS-4 is equipped with standard BNC, RCA and Binding post connectors, making it compatible with most laboratory-grade pH and ORP electrodes. For best results, we recommend Pinji E-series electrodes, which are calibrated for use with this instrument. Contact us for application-specific electrode recommendations.

How does the three-level user management work?

The Administrator level has full access to all instrument settings, calibration parameters and user management. The User level can perform measurements and access stored data but cannot modify system settings. The Visitor level allows read-only access to measurement results. All levels are password-protected and all operations are logged with operator ID and timestamp.

How do I connect the pHS-4 to a PC or LIMS?

The pHS-4 has USB and RS232 ports. Install the included USB driver and PC software to connect to a Windows PC. Data can be exported in CSV format for import into LIMS, Excel or other data management systems. RS232 is available for legacy systems and printers.

What is the recommended calibration frequency for the pHS-4?

For routine laboratory use, we recommend calibrating before each measurement session or at least once daily. At ±0.002 pH accuracy, the pHS-4 is sensitive to electrode aging and temperature variation, so fresh calibration is particularly important for high-precision applications. Replace the pH electrode every 12–18 months under normal use, or sooner if response becomes sluggish.

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