Rice Lake 820i, Technical Manual

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Appendix
© Rice Lake Weighing Systems ● All Rights Reserved 99
• The indicator address (65) is represented by an upper case “A”.
• The carriage return (CR) character is generated by pressing the
ENTER
key.
Therefore, to send the KPRINT command to the indicator at address 65, enter the following at the terminal:
CONTROL-B
, A, K,
P, R, I, N, T,
ENTER
.
The indicator responds with the format shown in Figure 10-3 :
<STX> ASCALE #1<EOL>
GROSS 1699 LB<EOL>
08/20/1998 10:05 AM<EOL>
<ETX> <CR>
If continuous transmission is configured for the serial port, the 820i sends data using the data format shown in Figure 10-4 :
Figure 10-4. RS-485 Continuous Data Format
10.7 Digital Filtering
Standard digital filtering uses mathematical averaging to eliminate the variant digital readings that the A/D converter sends
periodically because of external vibration. Digital filtering does not affect the indicator measurement rate, but does affect the
settling time. The selections from 1 to 256 reflect the number of readings averaged per update period. When a reading is
encountered that is outside a predetermined band, the averaging is overridden, and the display jumps directly to the new value.
DIGFLT
x
Parameters
The first three digital filtering parameters, DIGFLT1, DIGFLT2, and DIGFLT3, are configurable filter stages that control the effect
of a single A/D reading on the displayed weight. The value assigned to each parameter sets the number of readings received
from the preceding filter stage before averaging.
A rolling average is passed to successive filters for an overall filtering effect that is effectively a weighted average of the product
of the values assigned to the filter stages (
DIGFLT1 x DIGFLT2 x DIGFLT3)
within a time frame corresponding to the sum of the
values ( D D DIGFLT3) .
Setting the filters to 1 effectively disables digital filtering.
RATTLETRAP
®
Filtering
RATTLETRAP digital filtering (RATTRAP parameter set ON) uses a vibration-dampening algorithm to provide a combination of
the best features of analog and digital filtering. The RATTLETRAP algorithm evaluates the frequency of a repeating vibration
then derives a composite displayed weight equal to the actual weight on the scale less the vibration-induced flaws. It is
particularly effective for eliminating vibration effects or mechanical interference from nearby machinery. Using RATTLETRAP
filtering can eliminate much more mechanical vibration than standard digital filtering, but will usually increase settling time over
standard digital filtering.
DFSENS and DFTHRH Parameters
The digital filter can be used by itself to eliminate vibration effects, but heavy filtering also increases settling time. The DFSENS
(digital filter sensitivity) and DFTHRH (digital filter threshold) parameters can be used to temporarily override filter averaging
and improve settling time:
• DFSENS specifies the number of consecutive scale readings that must fall outside the filter threshold (DFTHRH) before
digital filtering is suspended.
• DFTHRH sets a threshold value, in display divisions. When a specified number of consecutive scale readings (DFSENS)
fall outside of this threshold, digital filtering is suspended. Set DFTHRH to NONE to turn off the filter override.
Response commands from
indicator:
<STX> <POL> <wwwwwww>
<L/K> <G/N> <S> <EOL>
NOTE:
This is the Consolidated
Controls continuous data format
<STX> <ADDRESS> <STREAM DATA> <ETX> <CR>
ASCII 02
decimal
Address of the
transmitting indicator
ASCII 13
decimal
ASCII 03
decimal