24
Network
Drive
Control
Input
(continued)
Using nviRefPcnt, the drive's reference is
expressed as a percentage of the reference
range. The range is set using parameters 204,
Min. Reference, and 205, Max. Reference. In
open loop operation, reference represents the
drive's desired output speed. In this case, set
Min. Reference to 0 Hz and Max. Reference
equal to Max. Frequency in parameter 202.
In closed loop operation, reference represents
the desired setpoint. It is recommended that
parameters 204 and 205 be set equal to
parameters 201, Min. Frequency, and 202,
Max. Frequency, respectively.
For closed loop operation, either
nviDriveSpeedSetpoint (state position of
SNVT_switch) or nviStartStop can be used to
enable/disable the drive.
All references provided to the drive are added
to the total reference value. If reference is to
be controlled by the LonWorks bus only, ensure
that all other reference inputs are zero. This
means that digital input terminals and analog
input terminals should not be used for reference
signals. The default setting (0%) should be
maintained for preset references in parameters
211 through 214. Also, in closed loop
operation, the default setting (0.0) should be
maintained for drive setpoints in parameters
418 and 419.
NOTE
To optimize network performance
and for proper drive operation, use
only one of following input
reference commands.
Reference 1
Network variable nviRefPcnt is a signed value.
It represents the desired percentage of the
TR1 drive's reference range.
Range: -163.840 - 163.835
Reference 3
Network variable nviRefHz is an unsigned
value. It represents the output frequency of
the drive in Hz in open loop. It is rarely used in
closed loop mode.
Range: 0 - 6553.5
Start/Stop and Reset fault
SNVT_lev_disc, ST_OFF and ST_NUL are
interpreted as low or “0.” ST_LOW, ST_MED,
ST_HIGH, and ST_ON are interpreted as high
or “1.”
The equivalent control word bit settings to start
and stop the drive (nviStartStop) and to reset
after a fault (nviResetFault) are described in
the table below.
Start/Stop and Fault Reset Control Word
Bit Descriptions
Bit 0 1 0 1 Description
Preset Ref LSB
Preset Ref MSB
No DC Brake
No Coast Stop
No Quick Stop
No Freeze Freq.
Start
Reset
Jog
No function
Bit 10
Relay 1 On
Relay 2 On
Setup LSB
Setup MSB
Reversing
nviStartStop nviResetFault
