For electrical and instrumentation, having and utilizing the right tools can make all the difference. Choosing between the Fluke 787 and 789 process meters isn’t easy when you need dependable equipment for electrical testing and calibration. Each one combines a 1000 volt CAT III/600 V CAT IV safety-rated digital multimeter with a full-featured mA loop calibrator in a single device. Both devices measure AC and DC volts, AC and DC current, resistance, continuity, and frequency with similar accuracy ratings. The Fluke 789, however, comes with extra features that you won’t find in the 787.
This piece will get into the most important differences between these process meters to help you choose the best option. You’ll learn which one fits your requirements better, whether you need simple loop testing or advanced process calibration capabilities.
Core Functional Differences Between Fluke 787 and 789
“The Fluke 789 has a 24-Volt loop supply reducing the need for taking a separate power supply when doing offline transmitter testing.” – Fluke
The Fluke 787 and 789 ProcessMeters have base functional differences that greatly affect their capabilities in field applications.
Loop Power Supply: Absent in 787 vs 24V in 789
The biggest difference is that the Fluke 789 has a built-in 24V loop power supply, while the 787 requires an external power supply. The 789’s power supply means you won’t need to carry extra equipment for offline transmitter testing. This makes life easier for process technicians as they can power and test devices with just one device.
HART Mode: Built-in 250Ω resistor in 789 vs Unavailable in 787
The 789 also has HART mode setting and loop power with a built-in 250Ω resistor, allowing communication with HART and other smart devices at the push of a button. Process technicians love this feature because they don’t need to carry a separate resistor when working with HART-compatible equipment.
Span Check Buttons: Manual toggle in 789 only
The 789 ProcessMeter comes with unique SpanCheck functionality and dedicated 0% and 100% buttons. These buttons help you switch between 4mA (0%) and 20mA (100%) quickly when sourcing current, making calibration and troubleshooting much easier with instant reference points. The 789’s dual display shows mA readings and percentage of scale values together, which is the most efficient way to handle calibration work.
Infrared I/O and Fluke Connect: Featured in both
Both models have an infrared I/O serial port and work with Fluke Connect. You can add an optional IR3000FC module to either multimeter to log data wirelessly through the Fluke Connect mobile app. This allows data to be sent to your smartphone and check it from anywhere, which reduces paperwork and stops manual data entry mistakes.
These functional differences will help technicians choose the right model for their specific field needs.
Measurement and Calibration Capabilities
The measurement and calibration specs show key similarities between the Fluke 787 and 789 ProcessMeters, despite their basic differences. These capabilities define how well they perform in daily industrial use.
Current Sourcing: 0-20 mA range in both
The Fluke 787 and 789 share current sourcing capabilities with a 0-20 mA or 4-20 mA range. You can choose your preferred range during power-up. Both models also work up to 24.000 mA, which gives extra room to test and calibrate instruments at the top of the standard 4-20 mA range.
Simultaneous mA and % Readout: Available in both
Both ProcessMeters can display current readings and percentage scale values at the same time. This feature saves time during loop testing because you don’t need manual calculations. You can see the actual current value and its scale position right away. The 789 does, however, come with a backlit display with 2 levels of brightness for easier readings in low light.
Accuracy: 0.05% span in both models
The Fluke 787 and 789’s measurement precision hits 0.05% of span. This precision remains constant across their measurement ranges. With either model, you’ll get lab-grade accuracy for critical process control and instrument calibration tasks.
Drive Capability: 1200Ω in both
Drive capability specs are the same on both models, offering 1200Ω drive capability at 20 mA with internal batteries [121]. This strong drive capability lets you power substantial loop resistance without losing performance. Both models can handle up to 1000Ω at 20 mA when simulating current with an external loop supply (15V to 48V). This feature works great in various field conditions.
These ProcessMeters build on the Fluke 87 digital multimeter’s trusted measurement capabilities. They add features to source, measure, and simulate mA current loops, making them perfect tools for professionals.
Build Quality and Usability
The Fluke’s ProcessMeters physical design and interface elements show their unwavering dedication to durability and usability in industrial environments.
Display and Interface: Backlit LCD with % scale in both
The Fluke 787 and 789 come with a backlit LCD display that shows mA and percentage of scale readings at the same time. The 789 stands out because its dual display is larger and offers two levels of backlighting for better visibilty in varying light conditions, allowing you to read measurements more easily in low-lit environments. Both models feature standard DMM capabilities with Min/Max/Average/Hold/Relative modes, diode test, and continuity beeper functions. These interface elements build on the Fluke 87 digital multimeter’s proven design, utilizing native controls to experienced Fluke users.
Battery and Fuse Access: External in both, but fuse access easier in 789
Both ProcessMeters have an externally accessible battery compartment, allowing quick battery replacement without opening the main housing. The 789 takes it one step further with fuses you can access from outside, while the 787 requires internal access for fuse replacement. This small difference becomes critical during field maintenance, especially when dealing with blown fuses. Both models utilize similar 440 mA 1000V fuses for protection.
Weight and Dimensions: Similar at 0.6 kg and 203x100x50 mm
The physical differences between Fluke 787 and 789 are minimal. Both ProcessMeters have similar dimensions at 203 mm x 100 mm x 50 mm (8.00 in x 3.94 in x 1.97 in). They weigh about the same at 0.6 kg (1.3 lbs)[151], though some sources list the 789 at 610 g (1.6 lbs). This consistent size means whatever model you choose, you’ll get a handheld tool that fits comfortably in standard tool bags and cases.
Fluke 789 Added Value: Worth the extra cost for advanced process calibration
The 789 ProcessMeter’s higher price brings specific advantages that make sense for many professionals. The built-in 24V loop power supply means a separate power source is not required. You’ll also save money with its built-in selectable 250-Ohm HART resistor. These features could save you more than the price difference, especially if you would need to buy these accessories separately.
Use Case Fit: 787 for simple loop testing, 789 for HART and loop power
Your specific needs will determine which model offers better value. The 787B is better suited for simple loop testing and general multimeter functions. It delivers 0.05% accuracy and all core measurement features at a lower price. The 789 becomes more affordable if you work with HART devices or need loop power for testing transmitters. Process technicians in chemical, pharmaceutical, biotechnology, and food industries find the 789’s extra features essential for their daily work.
The Fluke 789’s small price premium pays for itself through convenience and better workflow for advanced users. The 787B remains the smart choice if you have simpler needs.
Comparison Table
| Feature/Specification | Fluke 787 | Fluke 789 |
| Core Features | ||
| Loop Power Supply | Not available | Built-in 24V |
| HART Mode | Not available | Yes, with built-in 250Ω resistor |
| Span Check Buttons | Not available | Yes (0% and 100%) |
| Infrared I/O | Yes | Yes |
| Fluke Connect Compatible | Yes | Yes |
| Measurements & Calibration | ||
| Current Sourcing Range | 0-20mA/4-20mA | 0-20mA/4-20mA |
| Accuracy | 0.05% span | 0.05% span |
| Drive Capability | 1200Ω at 20mA | 1200Ω at 20mA |
| Simultaneous mA and % Readout | Yes | Yes |
| Physical Specifications | ||
| Dimensions | 203x100x50 mm | 203x100x50 mm |
| Weight | 0.6 kg | 0.6 kg |
| Display | Backlit LCD | Backlit LCD with dual levels |
| Battery Access | External | External |
| Fuse Access | Internal | External |
| Safety Rating | ||
| CAT Rating | CAT III 1000V/CAT IV 600V | CAT III 1000V/CAT IV 600V |
Your choice between the Fluke 787 and 789 ProcessMeters will depend on your testing needs and budget. These instruments share impressive features – they’re similar in measurement accuracy at 0.05% span, physical size, and safety ratings. Despite that, a few core differences explain why they’re priced differently.
The Fluke 789’s built-in 24V loop power supply and integrated 250Ω HART resistor give it a clear edge. You won’t have to carry extra equipment to test smart transmitters or communicate with HART devices. Additionally, it comes with SpanCheck and dedicated 0% and 100% buttons that make calibration easier and more efficient. This becomes really valuable when you regularly work with process instruments.
The Fluke 787 provides all the basic multimeter and loop calibration features at a lower price. While it may lack the fancy extras of its premium version, it provides the same accurate measurements and core features that made Fluke tools prominent. Technicians needing accurate measurements without the bells and whistles or on tight budgets will find great value in the affordable and capable 787.
These ProcessMeters are better than carrying separate multimeters and calibrators. They’re built on Fluke’s trusted 87 DMM technology that works reliably in tough industrial settings. Both tools meet strict safety standards with CAT III 1000V/CAT IV 600V ratings, providing confidence in your measurements.
Whether installing and commissioning transmitters in the field, performing plant/refinery maintenance, or calibrating instruments in a controlled environment, having the appropriate processmeter can make all the difference. The Fluke 787 and 789 both offer the Fluke standard of reliability, precision, and ruggedness, but the best choice ultimately comes down to your capability needs and the desired convenience in your workflow
FAQs
What are the main differences between the Fluke 787 and 789 ProcessMeters?
The key differences are that the Fluke 789 has a built-in 24V loop power supply, HART mode with a 250Ω resistor, and span check buttons, while the 787 lacks these features. Both models share core measurement capabilities and accuracy.
Which ProcessMeter is more suitable for basic loop testing?
The Fluke 787 is more suitable for basic loop testing as it offers essential functionality at a lower price point. It provides accurate measurements and core features without the advanced capabilities of the 789.
Does the Fluke 789 offer better value for advanced users?
Yes, the Fluke 789 offers better value for advanced users, especially those working with HART devices or frequently needing loop power. Its additional features, such as built-in loop power supply and HART mode, justify the slightly higher price for professionals in industries such as chemical, pharmaceutical, and biotechnology.
Are there any differences in the physical design between the two models?
Both models have identical dimensions and weight. However, the Fluke 789 has a larger display with two levels of backlighting and externally accessible fuses, while the 787 requires internal access for fuse replacement.
What is the accuracy of these ProcessMeters?
Both the Fluke 787 and 789 offer the same high accuracy of 0.05% of span across their shared measurement ranges, providing laboratory-grade precision for critical process control applications and instrument calibration tasks.
What kind of tasks is the Fluke 789 ideal for?
The Fluke 789 is ideal for troubleshooting current loops, calibrating smart transmitters and valve positioners, performing preventative maintenance, and other general electrical measurements
Does the Fluke 789 offer enhanced measurement accuracy?
Yes, the Fluke 789 offers 0.1% DC voltage accuracy and 0.05% DC current accuracy.
