Automatic Zero Drift Correction; Calibration - Tamper Detection; Reset Button; Zero-Drift Automatic Compensation Feature - London Electronics EasyReader ER4P Instruction Manual

Features
Automatic Zero-Drift Compensation
This cancels long-term zero drift due to ageing, temperature drift, etc. If the reading is within 7
counts of zero for around 100 seconds, the reading will go to zero without changing basic calibra-
tion. The correction is not stored when the meter is switched off and is cleared with a RESET
input. To activate this feature, set the display value at 0% input to MINUS ZERO ( -0)
Reset Input
Front panel or remote contact RESET command sets the Peak and Valley memories to latest
display value, clears Tare, automatic Zero compensation offset and clears digital filtering history
memory.
Peak and Valley Detection (Maximum/Minimum Reading View)
The meter stores the lowest and highest reading values in memory. Press the MAX/MIN front panel
button or remote contact to view. The first press shows peak, with the upper left hand indicator bar
lit. The second press shows valley, with the lower left hand indicator lit. The display returns to the
running value after 2 or 3 seconds. Peak and Valley values are not stored if you switch the meter
off. Clear memory with the RESETinput.
Tare Command
Press the front panel tare switch for more than 2 seconds, or make a momentary contact closure
to the TARE terminal and Common if you want to force the display to 0. Following readings will be
the 'net' value. The tare value is 'remembered' when the meter is switched off. You can clear this
memory with the RESET input.
Digital Filtering
A simple digital filter gives 'R-C' type time constants in the range 0 to 5 seconds. A value of 1
second gives a settling to 1% in around 5 seconds for a small step input. The filtering averages
ripple in the input signal. For 'large' steps of signal input the filtering is bypassed, to give a fast initial
response. You can reset the filtering by pressing the front panel reset switch for 2 to 3 seconds.
Last Digit Rounding
You can set the meter to count by 1,2,5,10,20 or 50 so that display flicker can be hidden.
Calibration Counter / Tamper detector
A internal totaliser counts each calibration. The 'C. XX' value appears for a second or two after you
switch the meter on. The number starts at 00 and can go up to FF (255 counts). It doesn't count
changes of filter value or count-by value in the 'theoretical calibration' menu. It stores the total in
non-volatile memory which can't be reset, useful for keeping track of the meter's calibration history.
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