High-Performance Process Multimeter 0.05% basic accuracy HART, and Harsh Environments 78+/79+/79A+

1. A Process Multimeter for Every Need – Three Accuracy Levels

The 78+, 79+, and 79A+ form a complete family of Process Multimeter instruments, designed to meet different precision requirements and budgets. The 78+ and 79+ offer a solid 0.20% basic accuracy, making them reliable workhorses for daily calibration and loop testing. The 79A+ raises the bar with an exceptional 0.05% basic accuracy, turning this Process Multimeter into a reference-class tool for demanding applications such as laboratory calibration, certified maintenance, and high-precision transmitter verification. Whichever model you choose, you are getting a true Process Multimeter built for industrial performance.

2. Dual Display with Temperature Measurement & Auto Cold-Junction Compensation

All three models in this Process Multimeter series feature an LCD dual display with backlight, allowing you to view two parameters simultaneously – such as mA and percentage, or voltage and temperature. The built-in temperature measurement with auto cold-junction compensation makes this Process Multimeter ideal for thermocouple and RTD circuit validation. No external reference junction is required, saving setup time and improving accuracy. Whether you are working in a furnace room or a refrigeration plant, this Process Multimeter delivers reliable temperature readings right out of the case.

3. Built-in 250Ω HART Loop Resistance – Seamless HART Communication

A standout feature of this Process Multimeter series is the built-in and selectable 250Ω HART loop resistance. HART communication requires a minimum loop resistance of approximately 250Ω for proper modem operation. Instead of carrying a separate resistor or hunting for one in your toolkit, you simply activate the internal resistor on this Process Multimeter. This allows you to connect a HART communicator or modem directly to the loop while the Process Multimeter continues to measure or source current. For instrument technicians working with smart transmitters, this feature alone makes the 78+/79+/79A+ the most convenient Process Multimeter on the market.

4. 24V Loop Power Supply with Simultaneous Current Measurement

Every model in this Process Multimeter series provides a 24V loop power supply that can power a 2-wire transmitter while simultaneously measuring the loop current. This is a core function of any professional Process Multimeter – you do not need an external power supply or a separate ammeter. Simply connect the transmitter to the Process Multimeter, turn on the 24V supply, and read the current directly. This streamlines transmitter testing, loop troubleshooting, and sensor validation, saving valuable time in the field.

5. Advanced Output Functions: Auto Ramp, Auto Step, 25%/100% Step

As a true Process Multimeter, the 78+, 79+, and 79A+ are not just measurement tools – they are also powerful signal sources. All models include:

• 25% and 100% step output – ideal for quick linearity checks of 4–20mA loops
• Auto ramp output – continuously ramps current up and down to test valve response and controller tuning
• Auto step output – automatically increments through preset values (e.g., 4, 8, 12, 16, 20mA) for hands-off testing

These functions transform the Process Multimeter into an automated calibrator, allowing you to perform repeatable tests without constant button pressing. The auto ramp and auto step are particularly valuable when testing chart recorders, data loggers, or slow-responding actuators.

6. IP65 Dustproof & Waterproof – Built for the Worst Conditions

Unlike ordinary handheld instruments, this Process Multimeter series is rated IP65, meaning it is completely protected against dust and resistant to low-pressure water jets from any direction. Additionally, the 78+/79+/79A+ carry safety ratings of 600V CAT.IV and 1000V CAT.III – the highest levels for industrial and utility applications. Whether you are working in a cement plant, a food processing facility, or an outdoor substation, this Process Multimeter will survive drops, splashes, and dust storms that would destroy lesser tools.

7. VFC Low-Pass Filter & Professional Measurement Features

The VFC (Variable Frequency Voltage Measurement) low-pass filter allows this Process Multimeter to accurately measure voltage in environments with variable frequency drives, inverters, and other noisy electrical equipment. Without a VFC filter, standard multimeters can display false readings due to harmonic distortion. This Process Multimeter cuts through the noise, giving you reliable measurements every time.

Other professional features include:

• Relative value measurement – zero out lead resistance or offset errors
• Manual/auto range selection – full control over how the Process Multimeter displays readings
• Data hold – freeze the display for easy recording
• Low battery indication – never be surprised by a dead unit
• Auto power-off – preserves battery life when the Process Multimeter is accidentally left on

8. Rugged, Reliable, and Ready for Daily Use

All three models are powered by standard batteries (details per model), feature a rugged enclosure, and come with standard accessories including test leads, alligator clips, fuses, and a manual. The dual LCD display with backlight ensures easy reading in dark panel rooms or outdoor night work. With the combination of high accuracy (0.05% on the 79A+), HART compatibility, IP65 protection, and CAT IV safety, the 78+/79+/79A+ series represents the pinnacle of what a Process Multimeter can be.