Series 550LX-504-4V2-10 SmartPack User's Manual Quad VDC Input
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nvo_pvout[ x ]: Process Variable Output
Declaration
network output SNVT_lev_percent nvo_pvout[ 4 ];
Description
This output network variable contains the latest value of the
corresponding analog input in units of SNVT_lev_percent.
The update rate for this variable is controlled by nci_pvdb[ x ]
and/or nci_pvtime[ x ]. The maximum update rate,
regardless of the source of control, is limited to 5 updates per
second.
Power-up/Reset Value
0% until first update occurs.
nci_pvdb[ x ]: Process Variable Deadband
Declaration
eeprom network input SNVT_lev_percent nci_pvdb[ 4 ];
Description
This configuration input network variable specifies the
deadband, or the amount of change in the input necessary to
cause an update of nvo_pvout[ x ]. Deadband is specified as
a percentage of the input span. As an example, for a
±
10V
input signal (20V input span) scaled to output
±
100%, 10%
deadband corresponds to 2V. As another example, for a 0
to 50V input signal scaled to output 0 to 100%, 10%
deadband corresponds to 5V. Deadband can be specified as
either positive or negative. Negative values are automatically
converted to positive values. Specifying a value of zero will
cause an update every 0.2 second. To disable "change-by"
updates, specify a large value such as 125% (25000). This
variable is maintained in EEPROM, and does not take effect
until the module is reset.
Initial Factory Value
0.01% (2).
nci_pvtime[ x ]: Process Variable Update Time
Declaration
eeprom network input SNVT_elapsed_tm nci_pvtime[ 5 ];
Description
This configuration input network variable specifies the period
of time between updates of nvo_pvout[x]. Internal resolution
is .2 second. The maximum allowable time expressed in
DD:HH:MM:SS:LL format is 00:03:38:27:000. Anything
greater will be clipped at 00:03:38:27:000. To disable
periodic updates,
set DD=65535, or all members to 0. This variable is
maintained in EEPROM, and does not take effect until the
module is reset.
Initial Factory Value
DD=65535, HH=00, MM=00, SS=00, LL=000: Periodic
updates disabled.
nci_pvtime[4]: Controls the update for nvo_struct_pvout
output structure variable.
nci_callo[ x ]: Calibration Low Variable
Declaration
eeprom network input SNVT_lev_percent nci_callo[ 4 ];
Description
This configuration input network variable contains the value
corresponding to the nominal zero-scale input. The value
must be less than the nci_calhi[ x ] value. See the
Calibration section for a complete description of its use. This
variable is maintained in EEPROM, and does not take effect
until the module is reset.
Initial Factory Value
-100.0% of span (-20000), for an applied input voltage of -
10VDC.
nci_calhi[ x ]: Calibration High Variable
Declaration
eeprom network input SNVT_lev_percent nci_calhi[ 4 ];
Description
This configuration input network variable contains the value
corresponding to the nominal full-scale input. The value
must be greater than the nci_callo[ x ] value. See the
Calibration section for a complete description of its use. This
variable is maintained in EEPROM, and does not take effect
until the module is reset.
Initial Factory Value
100.0% of span (20000), for an applied input voltage of
+10VDC.
Figure 3: Factory Calibration and Scaling (
±±±±
10VDC)
SNVT_lev % of
_percent span
30000 150
20000 100
10000 50
0 0
-15 -10 -5 0 5 10 15
V
IN
-10000 -50
-20000 -100
-30000 -150
nominal input range
SNVT_lev_percent = V
IN
x 2000
%-of-Span = V
IN
x 10
nvo_struct_pvout: Output Variable Structure
Process Variable Output Structure: This ouput network structure
contains the latest value of all analog inputs. The first member of
the structure corresponds to input 1, and so on. The data is
signed long –20000 to +20000 counts. The update rate for this
variable is controlled by nci_pvdb[x] and/or nci_pvtime[x]. The
