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Instruction Manual A75 Version 6 19th April 2004
BEKA associates Ltd, Old Charlton Road, Hitchin, Hertfordshire. SG5 2DA. UK. Tel: +44 (0) 1462 438301
8.5.7) “rEF” – Setting Internal References
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Do NOT enter this program parameter unless you have an accurate and
traceable signal source.
The internal references are used by the meter to calculate readings for the internal calibrator
(“cAL”), the units/percentage function (“U--P”) and the analogue output option. The internal references are protected against
accidental erasure or alteration by the operator having to enter the access word “SurE”.
The A75 can accept any one of twelve different input signal ranges. The input range is selected under the sub-menu option
“rAng”. See table 1 below for the choice of inputs. After selecting the input range, using an accurate signal source sample
signals associated with the “zero” and “span”. For example if the signal input range was 1-5V, 1V would need to be sampled
for the “zero” and 5V would need to be sampled for the “span”.
The 4-20mA analogue output (if fitted) can be adjusted (to a minimum of 3.8mA and a maximum of 22mA) using the up or
down buttons within the “SEt” options.
Please note to ensure maximum accuracy, whenever the input signal range of the indicator is changed as outlined in section
8.5.7, (for example, change the input from 0-10V to 4-20mA), the display should also be re-calibrated as outlined in section
8.5.6.
Table 1: Choice of input range and
the corresponding “rAng” settings
Input Range
"rAng" Setting
0-100mV
0.1u
0-200mV
0.2u
0-500mV
0.5u
0-1V
1u
0-2V
2u
0-5V
5u
0-10V
10u
0-20mA
0.02A
0-50mA
0.05A
1-5V
1-5u
4-20mA
4-20
10-50mA
10.50
8.5.8) “Iout” – 4-20mA Analogue Output. (If
fitted)
This parameter allows the 4-20mA analogue output to
be programmed to correspond to any part of the display
range. For example, the display range could be 0-500 Litres,
and the 4-20mA analogue output could be from 100-150
Litres. To set the actual mA output refer to section 8.5.7.
8.5.9) “F.Pan” - Front Panel Controls,
Password and Pushbutton Disable (anti-
tamper function).
The front panel controls (“F.PAn” parameters) allow a security
access password to be set or altered and allow the
pushbuttons to be enabled or disabled. If the “bttn” parameter
is “on”, then the pushbuttons will function normally, if the “bttn”
parameter is set to “off” then the pushbuttons will be disabled
(to re-enable see section 8.7). The security password set in
“CodE” will be the password required for anyone to gain
access to the Programming Mode. If password controlled
access is not needed, the code should be set to “0000” (four
zeroes).
If a password is forgotten, then the emergency access
code “FPAc” (“Forgotten Panel Access Code”) will
provide access
.
8.5.10) “ALr1” & “ALr2” –Alarm Setpoint
Programming (If Fitted).
Section 8.6) outlines the alarm parameters than can
be set.
8.6) The Alarm Parameters
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