Fluke 789 ProcessMeter Multimeter and mA Loop Calibrator
Overview
The Fluke 789 ProcessMeter combines a safety-rated true-rms digital multimeter with a milliamp loop calibrator in one compact handheld tool. Based on the measurement platform of the Fluke 87 multimeter, it adds the ability to measure, source and simulate 4 to 20 mA signals with the accuracy and resolution expected from a dedicated loop calibrator. For instrument and electrical technicians who normally carry a multimeter, a loop calibrator, a 24 V supply and a HART resistor to the field, the ProcessMeter replaces much of that kit with a single instrument.
Seven Star LLC supplies the Fluke 789 to instrumentation and maintenance departments across the Sultanate of Oman and the GCC, with engineering support in Muscat. In refineries, gas plants, water treatment works and power stations across the region, a large share of field work involves checking 4 to 20 mA loops between transmitters, control valves and the DCS or PLC, and this tool is designed precisely for that job.
Operating Principle
In source mode the Fluke 789 drives a precise current from its own batteries into a passive device such as an I/P converter, a valve positioner or a DCS analogue input, with 24 V compliance or 1200 Ω drive at 20 mA. In simulate mode it behaves like a two-wire transmitter, regulating the current flowing from an external 15 V to 48 V loop supply so the control system receives a known signal. In measure mode it reads loop current on a dedicated 30.000 mA range with 0.05% + 2 accuracy, while the display shows the reading as both mA and percentage of span.
The Fluke 789 also contains a built-in 24 V loop supply, so a transmitter can be powered and tested on the bench or offline in the field without a separate power unit. A selectable 250 Ω resistor can be switched into the loop in HART mode, giving a HART communicator the load it needs without carrying a separate resistor. Output can be stepped manually in coarse, fine, 25% or 100% increments, or set to Auto Step and Auto Ramp so the technician can watch a valve stroke or an alarm trip point while the meter sweeps the signal.
Engineering Design of the Fluke 789
As a multimeter the Fluke 789 measures dc voltage from 400.0 mV to 1000 V with 0.1% + 1 best accuracy, true-rms ac voltage to 1000 V, ac and dc current to 1 A (0.440 A continuous), resistance to 40 MΩ, frequency from 0.5 Hz to 20 kHz, diode voltage drop and continuity. Min/Max/Average, Hold and Relative modes are included. The inputs are rated CAT IV 600 V and CAT III 1000 V to IEC 61010, so the same tool used on an instrument loop can also be used safely on plant power circuits.
The housing measures 50 × 100 × 203 mm and weighs about 600 g. It runs on four AA batteries with a typical life of 140 hours for measurement and about 10 hours while sourcing, and both the batteries and the fuse are externally accessible for quick replacement. A large dual display with two levels of backlight helps in dark cabinets. Operation is specified from −20 °C to 55 °C, the meter has passed a one-metre drop test, and it carries a three-year warranty. With the optional IR3000FC adapter it connects to the Fluke Connect app for wireless logging and sharing of readings.
Key Features
The features that make the Fluke 789 a daily tool for loop troubleshooting and calibration are:
- Source, simulate and measure 0 to 20 mA or 4 to 20 mA, with over-range to 24 mA and 0.05% of span accuracy.
- Built-in 24 V loop supply for powering transmitters during offline tests.
- Selectable 250 Ω HART resistor in HART mode, removing the need for an external resistor.
- Simultaneous display of mA and percentage of scale for quick loop checks.
- Manual step (100%, 25%, coarse, fine), Auto Step and Auto Ramp outputs, with SpanCheck 0% and 100% buttons.
- 1000 V true-rms multimeter with 0.1% dc voltage accuracy and 0.05% dc mA accuracy.
- CAT IV 600 V / CAT III 1000 V safety rating for use on both instrument and power circuits.
- Optional Fluke Connect wireless logging through the IR3000FC module.
Industrial Applications
The Fluke 789 is used for loop checks during plant commissioning, for verifying analogue input cards in a DCS or PLC, for stroking control valves through their positioners, and for testing temperature transmitters such as the Rosemount 3144P Temperature Transmitter by powering them from the internal 24 V supply. When an alarm or trip does not behave as expected, the Auto Ramp function lets the technician find the exact current at which it acts.
Seven Star LLC supplies the Fluke 789 to instrument teams in Muscat, Sohar, Salalah and across the GCC. Where a team needs to read loop current without opening the circuit, the Fluke 773 Milliamp Process Clamp Meter complements it, and electricians who need higher current ranges and a 200 kHz frequency counter but no loop functions often prefer the Fluke 87V Industrial Multimeter.
Technical Specifications
The table below summarises the Fluke 789 specifications from the Fluke 787B and 789 ProcessMeter technical data sheet (18 °C to 28 °C, one year after calibration).
| Parameter | Specification |
|---|---|
| Model | Fluke 789 ProcessMeter |
| DC voltage | 400.0 mV to 1000 V; 0.1% + 1 |
| AC voltage (true-rms) | 400.0 mV to 1000 V; 0.7% + 2 |
| mA dc measure | 30.000 mA; 0.05% + 2 |
| A dc / A ac | 1.000 A (0.440 A continuous); 0.2% + 2 dc, 1% + 2 ac |
| Resistance | 400.0 Ω to 40 MΩ; 0.2% + 1 |
| Frequency | 0.5 Hz to 20 kHz; 0.005% + 1 |
| DC current output | 0 to 20 mA or 4 to 20 mA, over-range to 24 mA; 0.05% of span |
| Source drive capability | 24 V compliance or 1200 Ω at 20 mA |
| Simulate | External 15 V to 48 V loop supply; 1000 Ω at 20 mA |
| Loop supply | Minimum 24 V; 250 Ω at 20 mA |
| Safety | IEC 61010-2-033, CAT IV 600 V / CAT III 1000 V |
| Size and weight | 50 × 100 × 203 mm; approx. 600 g |
| Battery | Four AA; 140 h measuring, 10 h sourcing (typical) |
How to Order
To order the Fluke 789, send an RFQ to Seven Star LLC and include any accessories such as the IR3000FC Fluke Connect adapter, 80TK thermocouple module, i400 current clamp or TPAK hanger. Our instrumentation division in Muscat will confirm stock and delivery to sites across Oman and the GCC, and the ProcessMeter datasheet can be downloaded from this page for engineering review.
- Datasheet Fluke 787B and 789 ProcessMeter Datasheet Download
Fluke calibrators and test tools listed
The Fluke products on this page fall into three groups:- Process tools: the 754 documenting process calibrator with HART, 789 ProcessMeter, 721 dual sensor pressure calibrator and 729 automatic pressure calibrator
- Electrical test: the 376 FC true-RMS clamp meter with iFlex probe and the 1587 FC insulation multimeter
- Fluke Calibration bench standards: 5522A, 5502A, 5500A and 5080A multi-product calibrators, the 5720A multifunction calibrator, 8508A reference multimeter, 6100A electrical power standard and 9640A RF reference source
Where Fluke instruments are used
Fluke process calibrators are used for loop checks, transmitter calibration and valve tests in oil and gas, power and water plants. Clamp meters and insulation testers serve electrical maintenance on motors, switchgear and cables. The bench calibrators and reference multimeters are the working standards of electrical calibration laboratories in the GCC, where they calibrate multimeters, clamp meters, process tools and power analyzers.Ordering Fluke instruments: what we need
Send the exact model with its suffix, since versions differ. A Fluke 721, for example, is defined by its two pressure ranges, and a 729 by its maximum pressure. For bench calibrators, list the options you need, such as oscilloscope calibration or power quality options, the line voltage, and the type of calibration certificate you require from the manufacturer. For Fluke multimeters and clamp meters, add the kit contents wanted, such as probes, leads or cases.Browse Fluke products by category: Portable Test & Measurement.
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