5
AUTOMATIC ZERO TRACKING
The indicator can be programmed to automatically compensate for zero drift.
Drift may be caused by changes in the transducers or electronics, or
accumulation of material on weight systems.
Auto-zero tracking operates whenever the readout remains within the
tracking band for a period of time equal to the tracking delay time. When these
conditions are met, the indicator re-zeroes the readout. After the re-zero
operation, the indicator resets and continues to auto-zero track.
The auto-zero tracking band should be set large enough to track normal zero
drift, but small enough to not interfere with small process inputs.
For filling operations, the fill rate must exceed the auto-zero tracking rate.
This avoids false tracking at the start of the filling operation.
Fill Rate
≥
tracking band
tracking time
Auto-zero tracking is disabled by setting the tracking band parameter = 0.
Note: The Automatic Zero operation is blocked when the total accumulated zero
exceeds the value of the Zero Acquisition Range.
Note: The indicator does not have motion detection. Mechanical vibrations
coupled to the scale from other machinery may result in false Auto-Zero
operations.
DIGITAL FILTER
A unique adaptive input filter is used. Whenever the difference between one
reading and the next is less than the filter band value, the input is filtered. When
the difference exceeds the filter band value, the input is not filtered. This avoids
the usual compromise between using a relative high time constant for good
noise rejection and using a low time constant filter for quick step response.
FUNCTION KEYS
The Tare, Zero, and Print keys, in lieu of the standard function, can be
programmed for different functions, or no function at all. Additionally, the Tare
and Zero keys have second functions. The second function is activated after the
primary function if the key is held for 3 seconds.
MAX AND MIN READING DETECTION *
The indicator records the maximum (max) and minimum (min) process
inputs. Conditions such as valve activation, sudden change in material flow rate,
etc., can result in false peaks which are not reflective of the true maximum and
minimum of the process. In this case, Max and Min capture delay times can be
used to prevent the detection of false maximums and minimums.
TOTALIZER (integrator) *
The totalizer can be used to integrate a time-input product (such as flow). The
totalizer accumulates input readings according to the following relation:
Total(n) = Total(n-1) + [Input(n) * (scale factor/time base)]
n = nth sample instant (seconds)
input = input reading (ignore decimal point position)
scale factor = 0.001 to 65.000
time base: sec = 1
min = 60
hour = 3600
day = 86,400
When the total exceeds 5 digits, the front panel annunciator “T” flashes. In
this case, the indicator continues to totalize up to a 9 digit value. The high order
4 digits and the low order 5 digits of the total are displayed alternately. The letter
“
h
” denotes the high order display.
The total decimal point position is independent of the input. A low cut value
disables totalization below a set input value. Alarms can be programmed to
activate when a set total is reached.
Alternately, the totalizer can also be used to accumulate batch weighing
operations. Each time the batch function is executed, the weight is added to the
total and then zeroed.
PARAMETER LOCK MODE
A user input can be used to lock the parameter list.When the user input is
active, the indicator is in the protected parameter mode, where it is only possible
to access the setpoint values and the security code.
It is possible to lock the parameter list without using a user input as a program
lock function. In this case, set the security code to a non-zero value. With a non-
zero security value set, press the PAR key to view the programmed setpoint
values. The security code requires a matching “key” value to gain access to the
full parameter list.
BASIC OPERATION
TARE WEIGHT REGISTER
The indicator has a single Tare Weight register. There are two modes in which
Tare data is acquired: Pushbutton Tare and Digital Tare.
PUSHBUTTON TARE
Pushbutton Tare is activated by a single key press of the Tare In/Tare Out
Key.
Acquire Tare (Tare In):
Tare weight must be cleared, and Basic Weight Displayed.
Place Tare weight on scale.
Allow readout to stabilize.
Press key.
Indicator acquires the Tare weight with these actions:
If new Tare weight value >0, indicator displays “
'()*
” and selects Net
Weight display.
If new Tare weight < or = 0, indicator rejects Tare weight and displays
“
&+'()
”.
Clear tare (Tare Out):
Select Gross or Net Weight display.
Tare weight can be either on or off scale.
Press
to clear Tare weight
Indicator selects Basic Weight display.
DIGITAL TARE
Digital Tare allows a direct entry of the Tare Weight.
Enter Digital Tare:
Select the Tare Weight display.
Enter the Tare Weight using the Tare, Zero and Print keys. In this mode,
they take on data entry functions. Use the Tare key as an increment key
and the Zero key as a decrement key.
The “T” annunciator flashes to indicate Tare Weight entry.
Press the
PAR
key to register the Tare weight value. The indicator selects
either Net Weight display (new Tare Weight >0) or Basic weight display
(new Tare weight = 0).
Press the
TARA
key to abort the Tare entry mode.
PUSHBUTTON ZERO
Pushbutton Zero is activated by a single key press of the Zero Key.
To Zero:
Select Basic or Gross Weight display.
Allow readout to stabilize
Press
Key to re-zero the Gross Weight. Meter displays “
)*,*'
”.
Note: This operation is blocked when the total accumulated zero exceeds
the value of the Zero Acquisition Range.
PRINT TICKET
A ticket print is activated by a single key press of the Print Key.
To Print:
Place weight on scale and allow readout to stabilize.
Press
key.
(Print format is programmable in Module
-.$)/
.)
AUTOMATIC AND MANUAL ZERO ACQUISITION
There are two means by which the indicator keeps an accurate zero: Automatic
and Manual. The indicator saves the new zero state in an identical way in which
the Tare Weight is saved. See Tare Weight Entry for details of operation.
AUTOMATIC ZERO ACQUISITION
In Automatic mode, the indicator automatically re-zeros when the Gross
weight falls within a specified amount of scale divisions of zero (given by the
Autozero track band parameter) and remains within this band for a specified
amount of time (given by the Autozero track time). The indicator continues to
track zero in this fashion until the total accumulated zero offset exceeds the Zero
Acquisition Range. When exceeded, Autozero tracking is disabled.
Note: The indicator does not incorporate a means to detect stability. As a result,
scale vibration about zero may cause a false Auto-Zero operation.
