e
e
N
N
o
o
d
d
3
3
-
-
D
D
D
D
i
i
g
g
i
i
t
t
a
a
l
l
d
d
o
o
s
s
i
i
n
n
g
g
c
c
o
o
n
n
t
t
r
r
o
o
l
l
l
l
e
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r
r
e
Nod3-
D
: User’s instructions
165 752-A
14/23
low cut-off frequencies. The coefficients that define it depend on the A/D conversion rate and the wanted
cutt-off frequencies (that means the frequency band width). These coefficients can be easily calculated by
e
Nod
View
software.
- Self-adaptive filter : this filter can be set in cascade after previous filters. It is particularly efficient for
static measurements but avoid using it in dynamic or dosing processes. The aim of this filter is to
eliminate erratic measurements and to average consistent measurements.
10 TRANSMITTER FUNCTIONING MODE :
This basic functioning mode consists in transmitting measurements on the bus, possibly after configuring
them, filtering them and comparing them to set point levels.
Measurements can be transmitted individually regardless of the communication protocol or continuously
at a defined frequency in SCMBus (standard or fast format) or CANopen protocols.
Functioning may be unipolar (positive analog signal only) or bipolar (positive or negative analog signal).
10.1 Measurement reading request :
10.1.1 Single measurement transmission :
Regarless of the communication protocol in use.
The request can apply to :
-
gross measurement
-
net measurement
-
tare value
-
measurement in A/D converter points
10.1.2 Continuous measurement transmission
This is possible using standard or fast SCMBus format, the transmission can be started by a serial
command and another one allows stopping it. Measurements are transmitted at a period defined in ms by
the ‘sampling period’ setting.
The request can apply to
-
gross measurement
-
net measurement
-
measurement in A/D converter points
Note : This is very similar to operation of ‘Measurement window’ through an input command.
CANopen protocol also allows to define a period at which measurements are sent on the bus without any
master request.
10.2 Specific commands through an input :
10.2.1 Transmit measurement (Fig. 4)
This is only possible using standard or fast SCMBus format or CANopen protocols. The request can
apply to :
-
gross measurement
-
net measurement
-
measurement in A/D converter points
A single measurement is transmitted per rising or falling edge (depending on the configured logic) on the
input signal.
Fig. 4
