43
(Continued)
Send PID Setpoint:
There are two different ways of inputting a setpoint. The most common method is to simply use nviRefPcnt. in closed
loop operation, the reference is the setpoint reference. This value is sent as a percent. The other method requires the
use of SNVT_preset to directly access the appropriate drive parameter. This is not supported by Tracer Summit or
Rover.
Read back sensor value:
When the drive is in close loop mode (that is, using its internal PID controller), nvoOutputPcnt gives the value of the
feedback signal. This value is given in percent.
Monitor Volts, Amps, etc:
Most commonly monitored analog data from the TR1.
* nvoDrvCurrent - drive output current, in Amps
* nvoDrvEnrg - drive output energy, in kW-hr
* nvoDrvPower - drive output power, in kW
* nvoVoltage - drive output voltage, in V
* nvoDCVolt - drive internal DC bus voltage, in V
* nvoTempMtr - the status of the drive’s motor overload protection, in % of
the way to trip
* nvoTempInvrtr - the status of the drive’s own calculated thermal
protection, in % of the way to trip
Faults:
The drive’s LonWorks interface has an extensive set of alarm and warning outputs. These are presented in five
variables of the type SNVT_state. Each bit in each word represents a particular operating condition. These can be
general (like “running”, “warning” or “alarm”) or they can be quite specific (like “running at reference”, “hand or auto
mode”, “input phase loss”, and “current limit”).
Digital Inputs:
The TR1 LonWorks interface can also display the status of all eight of the drive’s hard-wired digital inputs, regardless
of whether they are being used to control the drive. This uses the variable nvoDigitalInput. Using this, it is possible to
wire external contacts to the drive and use the drive to report back their status.
Relay Control:
One other advanced capability of the TR1’s LonWorks interface is the ability of LonWorks to control the status of one
or both of the drive’s internal relays. Using this, it is possible to issue a LonWorks command that will, for example,
initiate motor alternation in a pumping application. To do this, nviControlWord is used to both control the status of the
relay(s) and to start and stop the drive. Currently not supported by Tracer Summit.
