2. Press REL to store the measured value and activate the relative measurement mode. The difference
between the reference value and the subsequent reading is displayed.
3. Press REL for more than 2 seconds to return the meter to normal operation.
b. Measurement Functions
• AC and DC Voltage Measurement
To avoid electrical shock and/or damage to the instrument, do not attempt to measure
voltages exceeding 1,000VDC / 1,000VAC RMS.
To avoid electrical shock and/or damage to the instrument, do not apply more 1,000VDC or
1,000VAC RMS between the COM terminal and the earth ground.
The meter's voltage ranges are 400.0mV, 4.000V, 40.00V, 400.0V and 1,000V. AC 400.0mV range only exists in
manual ranging mode.
To measure AC or DC voltages:
1. Set the rotary switch to the proper range.
2. Connect the black and red test leads to the COM and V terminals respectively.
3. Connect the test leads to the circuit being measured.
4. Read the displayed value. The polarity of the red test lead connection will be indicated when making a DC
measurement.
NOTE: The displayed values may be unstable especially at 400mV range, even though you do not put the test
leads into the input terminals. If an erroneous reading is suspected, short the V and the COM terminal and
make sure the LCD displays a zero value. For better accuracy, measure the AC voltage first. Note the AC
voltage range and manually select a DC voltage range equal to or higher than the AC range. This
improves the DC measurement by ensuring that the input protection circuits are not activated.
• Resistance Measurement
To avoid electrical shock and/or damage to the instrument, disconnect the circuit power and
discharge all high-voltage capacitors before measuring resistance.
The meter's resistance ranges are 400.0 , 4.000k , 40.00k , 400.0k , 4.000M and 40.00M .
To measure resistance:
1. Set the rotary switch to the proper range.
2. Connect the black and red test leads to the COM and
3. Connect the test leads to the circuit being measured and read the displayed value.
NOTE: The measured value of a resistor in a circuit is often different from the resistor's rated value. This is
because the meter's test current flows through all possible paths between the probe tips. In order to
ensure the best accuracy in measurement of low resistance, short the test leads before measurement and
remember the test probe resistance. This is necessary to subtract the resistance of the test leads.
The resistance function can produce enough voltage to the forward bias silicon diode or transistor
junctions, causing them to conduct. To avoid this, do not use the 40M range for in-circuit resistance
measurements. On the 40M range, the meter may need a few seconds to stabilize the reading. This is
normal for high resistance measuring. When the input is not connected, i.e. at open circuit, OL will be
displayed for the overrange condition.
DVM1100
terminals respectively.
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VELLEMAN