28 II Ex True-rms Digital Multimeter Users Manual November 2011 Rev. 1, 10/17 © 2011-2017 Fluke Corporation. All rights reserved. Specifications are subject to change without notice. All product names are trademarks of their respective companies.
LIMITED WARRANTY AND LIMITATION OF LIABILITY This Fluke product will be free from defects in material and workmanship for three years from the date of purchase. This warranty does not cover fuses, disposable batteries, or damage from accident, neglect, misuse, alteration, contamination, or abnormal conditions of operation or handling. Resellers are not authorized to extend any other warranty on Fluke’s behalf.
Table of Contents Title Page Introduction .................................................................................................................... How to Contact Fluke ..................................................................................................... Safety Information .......................................................................................................... Ex Safety Information ...............................................................................
28 II Ex Users Manual Resistance Measurements ....................................................................................... How to Use Conductance for High Resistance or Leakage Tests ............................ Capacitance Measurements ..................................................................................... Diode Tests ............................................................................................................... AC or DC Current Measurements ........................
Contents (continued) Frequency Counter Sensitivity and Trigger Levels .................................................... Duty Cycle (Vdc and mVdc) ...................................................................................... Input Characteristics .................................................................................................. MIN MAX Recording ..................................................................................................
28 II Ex Users Manual iv
Introduction How to Contact Fluke XW Warning Read “Safety Information” before using the Product. The 28 II Ex Digital Multimeter (the Product) is a compact easy to operate measurement tool for electrical and electronic circuits. Read the entire Users Manual and the Safety Instructions before you use the Product.
28 II Ex Users Manual XW Warning Safety Information A Warning identifies conditions and procedures that are dangerous to the user. A Caution identifies conditions and procedures that can cause damage to the Product or the equipment under test. To prevent electric shock or personal injury while in Ex-HAZARDOUS areas, follow these guidelines: • Symbols used on the Product and in this manual are explained in Table 1. Do not open the Product while in an Ex-hazardous area.
True-rms Digital Multimeter Ex Safety Information • The Product must be completely and securely fitted in the red holster while it is in an Ex-hazardous area. • Use only approved accessories with this Product in Ex-hazardous areas. • Do not use the Product in aggressive acidic or alkaline solutions. For applications requiring Group I equipment, avoid permanent contact of the Product with oil, hydraulic fluid, or grease. • Do not use the Product in zones 0, 20, 21, or 22.
28 II Ex Users Manual 4 • Do not use the Product in damp or wet environments. • Do not exceed the Measurement Category (CAT) rating of the lowest rated individual component of a Product, probe, or accessory. • Examine the case before you use the Product. Look for cracks or missing plastic. Carefully look at the insulation around the terminals. • Do not use test leads if they are damaged. Examine the test leads for damaged insulation, exposed metal, or if the wear indicator shows.
True-rms Digital Multimeter Ex Safety Information • Measure a known voltage first to make sure the Product operates correctly. • Measure for hazardous voltage without the Low-Pass Filter. • Do not apply more than the rated voltage, between the terminals or between each terminal and earth ground. • Do not touch the probes to a voltage source when the test leads are connected to the current terminals.
28 II Ex Users Manual WCaution To prevent possible damage to the Product or to the equipment under test, follow these guidelines: 6 • Disconnect circuit power and discharge all high-voltage capacitors before testing resistance, continuity, diodes, or capacitance. • Use the proper terminals, function, and range for all measurements. • Before measuring current, check the fuses in the Product. (See Fuse Test.
True-rms Digital Multimeter Errors and Load Restrictions Table 1. Symbols W WARNING - RISK OF DANGER. Consult user documentation. X WARNING. HAZARDOUS VOLTAGE. Risk of electric shock. T Double Insulated Capacitance AC (Alternating Current) DC (Direct Current) P Conforms to European Union directives. Earth Conforms to relevant South Korean EMC Standards. Fuse ( Conforms to the European Explosive Atmospheres (ATEX) directive. Battery. Low battery when displayed.
28 II Ex Users Manual Features Tables 2 through 5 show the features of the Product. Table 2. Inputs 2 1 4 3 grt01.eps 8 Item Terminal Description A Input for voltage, continuity, resistance, diode, capacitance, frequency, temperature, and duty cycle measurements. Input for 0 μA to 400 mA current measurements (600 mA for 18 hrs) and current frequency and duty cycle. COM Input for 0 A to 10.
True-rms Digital Multimeter Features Table 3. Rotary Switch Positions Switch Position Any Position J M Function When the Product is turned on, the Product model number briefly shows on the display. AC voltage measurement Push (yellow) for low-pass filter (K) DC voltage measurement 600 mV dc voltage range Push (yellow) for temperature () Push E for continuity test. N e Resistance measurement Push (yellow) for capacitance measurement. O Diode test P AC current measurements from 0 mA to 10.
28 II Ex Users Manual Table 4. Pushbuttons Button Switch Position N (Yellow) C D 10 Function Set to capacitance M Set to temperature J Turn on ac low-pass filter P Set dc or ac current Q Set dc or ac current Any position Change and set the range for the set function. To go to autoranging, hold the button down for 1 second. M Sets to °C or °F. Any position MIN MAX recording Frequency counter AutoHOLD (formerly TouchHold) captures the current measurement on the display.
True-rms Digital Multimeter Features Table 4. Pushbuttons (cont.) Button Switch Position Toggle the continuity beeper on and off. E Continuity N MIN MAX recording Hz, Duty Cycle H Any position Turns on the button backlight and display backlight, makes them brighter, and turns off the backlights. Hold H down for 1 second to enter the HiRes digit mode. The “HiRes” icon shows in the display. To go back to the 3-1/2 digit mode, hold H down for 1 second. HiRes=19.999.
28 II Ex Users Manual 8 7 9 10 11 Number Feature Indication - Negative measurement. In relative mode, this sign shows that the input is less than the stored reference. Z High voltage present at the input. Appears if the input voltage is 30 V or greater (ac or dc). Also shows in low-pass filter mode. Also shows in cal, Hz, and duty cycle modes. RS S Display HOLD is active. Peak Min Max modes and the response time is 250 μs.
True-rms Digital Multimeter Features Table 5. Display Features (cont.) Number Feature Indication Low battery. XW Warning: To A, μA, mA avoid false readings, which could lead to possible electric shock or personal injury, replace the battery as soon as the battery indicator appears. amperes (amps), microamp, milliamp V, mV volts, millivolts μF, nF microfarad, nanofarad nS nanosiemens % Percent. Used for duty cycle measurements.
28 II Ex Users Manual Table 5. Display Features (cont.) Number Feature -- Indication Overload condition is detected. Error Messages Replace the battery immediately. In the capacitance function, too much electrical charge is on the capacitor under test. Invalid calibration data. Calibrate Product. Invalid EEPROM data. Have the Product serviced. Open thermocouple detected. Invalid model. Have the Product serviced. W Test lead alert.
True-rms Digital Multimeter Features Power-Up Options To set a power-up option, push a button from the list in Table 6 as you turn on the Product. Table 6. Power-Up Options Button (Yellow) Power-Up Option Disables automatic power-off feature (Product normally powers off in 30 minutes). The Product reads “” until is released. Sets the Product in calibration mode and prompts for a password. The Product shows “” in the display and enters calibration mode. See 28 II Ex Calibration Information.
28 II Ex Users Manual How to Make Measurements AC Voltage The Product features true-rms measurements, which are accurate for distorted sine waves and other waveforms (with no dc offset) such as square waves, triangle waves, and staircase waves. AC and DC Voltage Measurements The voltage ranges of the Product are 600.0 mV, 6.000 V, 60.00 V, 600.0 V, and 1000 V. To select the 600.0 mV dc range, turn the rotary switch to . Switch Box V Refer to Figure 2 to measure ac or dc voltage.
True-rms Digital Multimeter How to Make Measurements When you measure voltage, the Product puts approximately 10-MΩ (10,000,000 Ω) impedance in parallel with the circuit. This loading effect can cause measurement errors in high-impedance circuits. In most cases, the error is negligible (0.1 % or less) if the circuit impedance is 10 kΩ (10,000 Ω) or less. For better accuracy when you measure the dc offset of an ac voltage, measure the ac voltage first.
28 II Ex Users Manual Low-Pass Filter The Product has an ac low-pass filter. When you measure ac voltage or ac frequency, push to set the low-pass filter mode (K). The Product measures in the chosen mode, but the signal diverts through a filter that stops unwanted voltages more than 1 kHz, refer to Figure 3. The lower frequency voltages go through with decreased accuracy to the measurement less than 1 kHz.
True-rms Digital Multimeter How to Make Measurements Temperature Measurements The Product measures the temperature of a type-K thermocouple (included). Push C to toggle between degrees Celsius (°C) or degrees Fahrenheit (°F). W Caution To prevent damage to the Product or other equipment, remember that while the Product is rated for -200.0 °C to +1090.0 °C (-328.0 °F to 1994 °F), the included type-K thermocouple is rated to 260 °C. For temperatures out of that range, use a higher rated thermocouple.
28 II Ex Users Manual For in-circuit tests, turn circuit power off. ON (closed) OFF (open) Activates continuity beeper grt03.eps Figure 4.
True-rms Digital Multimeter How to Make Measurements Resistance Measurements Some guidelines for resistance measurements are: • To prevent damage to the Product or to the equipment under test, disconnect the power and discharge all high-voltage capacitors before you measure resistance. The measured value of a resistor in a circuit can be different from the resistor's rated value. • The Product sends a small current through the circuit to measure resistance.
II Ex Users Manual In-Circuit Resistance Measurements Isolating a Potentiometer Circuit Power OFF 1 3 2 Disconnect 2 1 3 Isolating a Resistor Disconnect grt04.eps Figure 5.
True-rms Digital Multimeter How to Make Measurements How to Use Conductance for High Resistance or Leakage Tests Conductance, the inverse of resistance, is a measure of how easily current goes through a circuit. High values of conductance are the same as low values of resistance. The 60-nS range of the Product measures conductance in nanosiemens (1 nS = 0.000000001 siemens).
28 II Ex Users Manual Capacitance Measurements WCaution To prevent damage to the Product or to the equipment under test, disconnect circuit power and discharge all high-voltage capacitors before you measure capacitance. Use the dc voltage function to make sure that the capacitor is discharged. Select Capacitance The capacitance ranges of the Product are 10.00 nF, 100.0 nF, 1.000 μF, 10.00 μF, 100.0 μF, and 9999 μF. To measure capacitance, set up the Product as shown in Figure 6.
True-rms Digital Multimeter How to Make Measurements Diode Tests WCaution To prevent damage to the Product or to the equipment under test, disconnect circuit power and discharge all high-voltage capacitors before you do a diode test. Use the diode test to examine diodes, transistors, silicon controlled rectifiers (SCRs), and other semiconductor devices. This test sends current through a semiconductor junction, while it measures the junction's voltage drop. A good silicon junction drops between 0.5 V and 0.
28 II Ex Users Manual Reverse Bias Forward Bias Typical Reading + + Single Beep Shorted Bad Diode Open Bad Diode or grt06.eps Figure 7.
True-rms Digital Multimeter How to Make Measurements AC or DC Current Measurements XWWarning To prevent electric shock or personal injury, do not try an in-circuit current measurement where the open-circuit potential to earth is larger than 1000 V. You can cause Product damage or personal injury if the fuse blows. WCaution To prevent damage to the Product or to the equipment under test: • Examine the fuses of the Product before you measure current.
28 II Ex Users Manual Circuit Power: OFF to connect meter. ON for measurement. OFF to disconnect meter. 1 Total Current to Circuit 4 mA A 3 A 5 2 Current Through One Component 5 grt07.eps Figure 8.
True-rms Digital Multimeter How to Make Measurements 3. If you use the A terminal, set the rotary switch to mA/A. If you use the mA/μA terminal, set the rotary switch to Q for currents below 6000 μA (6 mA), or P for currents above 6000 μA. 4. To measure dc current, push . 5. Open the test circuit path. Touch the black probe to the more negative side of the break. Touch the red probe to the more positive side of the break.
28 II Ex Users Manual Frequency Measurements Some guidelines for frequency measurements are: For frequency measurements, the Product counts the number of times the signal crosses a set voltage level each second. • If a measurement shows as 0 Hz or is unstable, the input signal can be below or near the trigger level. To correct these problems, go to a lower range, which increases the sensitivity of the Product. In the function, the lower ranges also have lower trigger levels.
True-rms Digital Multimeter How to Make Measurements Table 7. Functions and Trigger Levels for Frequency Measurements Approximate Trigger Level Typical Application Function Range 6 V, 60 V, 600 V, 1000 V ±5 % of scale Most signals. 600 mV ±30 mV High-frequency 5 V logic signals. (The dc-coupling of the function can attenuate high-frequency logic signals, reducing their amplitude enough to interfere with triggering.
28 II Ex Users Manual To measure duty cycle, set up the Product to measure frequency. Then push G a second time. As with the frequency function, push E to change the slope for the counter. Duty Cycle Measurements Duty cycle (or duty factor) is the percentage of time a signal is above or below a trigger level in one cycle (Figure 9). The duty cycle mode is optimized to measure the on or off time of logic and switching signals.
True-rms Digital Multimeter HiRes Mode How to Determine Pulse Width For a periodic waveform (its pattern repeats at equal time intervals), you can find the time that the signal is high or low as follows: 1. Measure the signal's frequency. 2. Push G a second time to measure the signal's duty cycle. Push E to select a measurement of the signal's positive or negative pulse, refer to Figure 9. 3. HiRes Mode On the Product, push H for one second to enter the highresolution (HiRes) 4-1/2 digit mode.
28 II Ex Users Manual MIN MAX Recording Mode The MIN MAX mode records minimum and maximum input values. When the inputs go below the recorded minimum value or above the recorded maximum value, the Product beeps and records the new value. This mode can be used to record intermittent measurements, record maximum measurements while you are away or record measurements while you operate the equipment under test and cannot look at the Product.
True-rms Digital Multimeter Smooth Feature (Power Up Option Only) Table 8. MIN MAX Functions Button MIN MAX Function Enter MIN MAX recording mode. The Product is locked in the range shown before you started MIN MAX mode. (Set the measurement function and range before you enter MIN MAX.) The Product beeps each time a new minimum or maximum value is recorded. (while in MIN MAX mode) E PEAK MIN MAX D (hold for 1 second) Step through maximum (MAX), minimum (MIN), average (AVG) and current values.
28 II Ex Users Manual AutoHOLD Mode XWWarning To prevent electrical shock or personal injury, do not use AutoHOLD mode to see if circuits are without power. The AutoHOLD mode will not hold on unstable or noisy measurements. The AutoHOLD mode locks the current measurement on the display. When a new, stable measurement is sensed, the Product beeps and shows the new measurement. To start or exit AutoHOLD mode, push D.
True-rms Digital Multimeter Maintenance Fuse Test Maintenance XWWarning To prevent electrical shock or personal injury, have the Product repaired by ECOM Instruments GmbH or an ECOM authorized service center to keep Product certification. General Maintenance To clean the external surfaces of the Product, wipe the case with a damp cloth and mild detergent. Do not use abrasives or solvents. Dirt or moisture in the terminals can cause incorrect measurements and can falsely set off the Input Alert feature.
28 II Ex Users Manual How to Replace the Batteries Good 0.44 A fuse: 0.995 kΩ to 1.005 kΩ Replace the batteries with three AAA batteries (NEDA 24A IEC LR03). Replace fuse: OL XWWarning To prevent electrical shock or personal injury: Touch top half of input contacts Good 11 A fuse: 0.0 Ω to 0.5 Ω Replace fuse: OL grt08.eps Figure 10. Current Fuse Test 38 • Replace the batteries when the low battery indicator () shows to prevent incorrect measurements.
True-rms Digital Multimeter Maintenance Replace the batteries as follows, refer to Figure 11: 1. Turn the rotary switch to OFF and remove the test leads from the terminals. 2. Remove the six Torx-head screws from the case bottom and remove the battery door (). Note When you lift the battery door, make sure the rubber gasket stays attached to the battery compartment barrier. 3. Remove the three batteries and replace all three with AAA Alkaline batteries (). 4.
28 II Ex Users Manual 1 3 2 5 4 grt10.eps Figure 11.
True-rms Digital Multimeter Service and Parts assembly. You must use a new fuse assembly to replace the 440 mA fuse. How to Replace the Fuses Examine or replace the fuses in the Product as follows (See Figure 11): 6. Install the fuse assembly into the fuse compartment. 1. Turn the rotary switch to OFF and remove the test leads from the terminals 7. Refer to How to Replace the Batteries to replace the battery door. 2. Refer to step 2 in How to Replace the Batteries to remove the battery door.
28 II Ex Users Manual Table 9. Replacement Parts Description Qty. Fluke Part or Model Number Fuse, 11 A, 1000 V, FAST 1 803293 28 II Ex Fuse Assembly 1 4016494 Alligator Clip, Black 1 Alligator Clip, Red 1 Test Lead Set 1 TL175 28 II Ex Getting Started Manual 1 3945752 Fluke Input Cap, Amp Jack Plugs for DMMs (10 pack) 1 4145825 W To ensure safety, use exact replacement only.
True-rms Digital Multimeter Service and Parts Alligator Clips Fuse Assembly *Contains 440 mA Fuse Test Lead Set Fuse 11 A, 1000 V, Fast Amp Jack Plug set 28 II Ex Getting Started grt11.eps Figure 12.
28 II Ex Users Manual General Specifications Maximum voltage between any terminal and earth ground ........................................... 1000 V W Fuse for mA inputs .................................................. 0.44 A, 1000 V IR 10 kA W Fuse for A inputs ..................................................... 11 A, 1000 V IR 17 kA Display ........................................................................... 6000 counts, updates 4/sec (19,999 counts in high-resolution mode).
True-rms Digital Multimeter General Specifications Safety General ....................................................................... IEC 61010-1: Pollution Degree 2 Measurement .............................................................. IEC 61010-2-033: CAT IV 600V / CAT III 1000V Ingress Protection ....................................................... IEC 60529: IP67, non-operating Electromagnetic Compatibility (EMC) .........................
28 II Ex Users Manual Detailed Specifications For all detailed specifications: Accuracy is specified for 2 years after calibration, at operating temperatures of 18 °C to 28 °C, with relative humidity at 0 % to 80 %. Accuracy specifications take the form of ±([% of Reading] + [Number of least-significant digits]). In the 4 ½-digit mode, multiply the number of least-significant digits (counts) by 10. AC Voltage AC conversions are ac-coupled and valid from 3 % to 100 % of range. Range Resolution 600.
True-rms Digital Multimeter Detailed Specifications DC Voltage, Conductance, and Resistance Function mV dc V dc Ω nS [1] [2] [3] Range Resolution Accuracy 600.0 mV 0.1 mV ±(0.1 % + 1) 6.000 V 60.00 V 600.0 V 1000 V 0.001 V 0.01 V 0.1 V 1V ±(0.05 % + 1) 600.0 Ω 0.1 Ω ±(0.2 % + 2) [2] 6.000 kΩ 0.001 kΩ 60.00 kΩ 0.01 kΩ ±(0.2 % + 1) 600.0 kΩ 0.1 kΩ 6.000 MΩ 0.001 MΩ 50.00 MΩ 0.01 MΩ ±(1.0 % + 3) [1,3] 60.00 nS 0.01 nS ±(1.0 % + 10) [1,2,3] ±(0.6 % + 1) Add 0.
28 II Ex Users Manual Temperature Range -200 °C to +1090 °C -328 °F to +1994 °F [1] [2] Resolution 0.1 °C 0.1 °F Accuracy [1,2] ±(1.0 % + 10) ±(1.0 % + 18) Does not include error of the thermocouple probe. Accuracy specification assumes ambient temperature stable to ± 1 °C. For ambient temperature changes of ± 5 °C, rated accuracy applies after 2 hours. AC Current Function μA ac mA ac A ac [1] [2] [3] [4] 48 Range Resolution Burden Voltage 600.0 μA 0.1 μA 100 μV/μA 6000 μA 1 μA 100 μV/μA 60.
True-rms Digital Multimeter Detailed Specifications DC Current Function μA dc mA dc A dc [1] [2] [3] Range Resolution Burden Voltage Accuracy 600.0 μA 0.1 μA 100 μV/μA ±(0.2 % + 4) 6000 μA 60.00 mA 1 μA 0.01 mA 100 μV/μA 1.8 mV/mA ±(0.2 % + 2) 400.0 mA [1] 6.000 A 0.1 mA 1.8 mV/mA ±(0.2 % + 2) 0.001 A 0.03 V/A ±(0.2 % + 4) A [2,3] 0.01 A 0.03 V/A ±(0.2 % + 2) 10.00 ±(0.2 % + 4) 400 mA continuous; 600 mA for 18 hr maximum. W 10 A continuous up to 35 °C.
28 II Ex Users Manual Diode Range Resolution 2.000 V 0.001 V Accuracy ±(2.0 % + 1) Frequency Range Resolution 199.99 Hz 1999.9 Hz 19.999 kHz 199.99 kHz >200 kHz [1] 0.01 Hz 0.1 Hz 0.001 kHz 0.01 kHz 0.1 kHz Accuracy ±(0.005 % + 1) [1] Unspecified From 0.5 Hz to 200 kHz and for pulse widths > 2 μs. Frequency Counter Sensitivity and Trigger Levels Minimum Sensitivity (RMS Sine Wave) 5 Hz – 20 kHz 0.
True-rms Digital Multimeter Detailed Specifications Duty Cycle (Vdc and mVdc) Range 0.0 % to 99.9 [1] [2] Accuracy Within ± (0.2 % per kHz + 0.1 %) for rise times <1 μs. [2] % [1] 0.5 Hz to 200 kHz, pulse width >2 μs. Pulse width range is determined by the frequency by the frequency of the signal. For 6 V dc range accuracy is unspecified.
28 II Ex Users Manual MIN MAX Recording Nominal Response 100 ms to 80 % (dc functions) 120 ms to 80 % (ac functions) 250 μs (peak) [1] [1] 52 For 6 V range: 1 ms Accuracy Specified accuracy ±12 counts for changes >200 ms in duration Specified accuracy ±40 counts for changes >350 ms and inputs >25 % of range Specified accuracy ±200 counts for changes >250 μs in duration (add ±100 counts for readings over 6000 counts) (add ±100 counts for readings in Low Pass mode)
