LDU 179.1 Technical Manual rev. 1.10 - February 2019 Page 29 of 45
8.3.
Motion Detection Commands
– NR, NT
The motion detection facility provides a means of disabling certain functions whenever a condition of instability,
or “motion”, is detected. The “no motion” or “stable” condition is achieved whenever the signal is steady for the
period of time set by NT, during which it cannot fluctuate by more than NR increments. The stable condition
activates the relevant bit of responses to “Info Status” (IS).
Following functions are disabled if motion is detected: “Calibrate Zero” (CZ) “Calibrate Gain” (CG) “Set Zero”
(SZ) and “Set Tare” (ST). After such a command the system returns an error (“ERR“), if the signal is not stable.
8.3.1. NR Set No-motion Range
[ SDO 2100 sub 0A ]
This is the range within which the weighing signal is allowed to fluctuate and still be considered as “stable”.
Permitted values are from 0 to 65535.
Master (PC / SPS) sends
Slave (LDU 179.1) responds
Meaning
NR
R+000010
Request: NR = 10 d
NR2
OK
Setup: NR = 2 d
WP
OK
Setup saved
Example: For NR = 2 the fluctuations within a maximum of ± 2 d, in the period NT, will be considered
“stable”.
Factory default: NR = 1 [= ±1d]
8.3.2. NT Set No-motion Time
[ SDO 2100 sub 0B ]
This is the period of time (in milliseconds) over which the weight signal is checked to be
“stable” or not. The
weight signal has to vary by less than NR divisions over the period of time NT to be considered
‘stable’.
Permitted values are from 0 to 65535.
Master (PC / SPS) sends
Slave (LDU 179.1) responds
Meaning
NT
T+001000
Request: NT = 1000 ms
NT500
OK
Setup: NT = 500 ms
WP
OK
Setup saved
If the value of NT = 500 milliseconds, the output must not fluctuate more than NR increments within 500
milliseconds in order to be considered “stable”.
Factory default: NT = 1000 [ms]
8.4.
Filter Setting Commands
– FM, FL, UR
A digital filter can be set which will eliminate most of the unwanted disturbances. The commands
FM
and
FL
are used to define the digital filter settings, the command
UR
is used to define an averaging of up to 128
measurement values. Please note that these filters are positioned immediately after the A/D Converter and
therefore affect all aspects of the weighing operation.
8.4.1. FM Filter Mode
[ SDO 2100 sub 09 ]
This command defines the filter mode. Choose the filter mode for your application.
Permitted values are “0” for IIR filter and “1” for FIR filter.
Master (PC / SPS) sends
Slave (LDU 179.1) responds
Meaning
FM
M+00000
Request: FM = 0 (IIR filter)
FM0
OK
Setup: FM = 0 (IIR filter)
WP
OK
Setup saved
The digital IIR filter operates as 2
nd
order low pass filter and Gaussian characteristics. The attenuation is
40dB/decade (12 dB/octave).
The digital FIR filter works as a low-pass filter with quick response; damping see table mode 1.
Default setting:
0 (IIR filter)
