When the
PO1-PO3 Setpoint Description parameters are changed the process output data are
automatically disabled through the
Enable Fieldbus Setpoints = NO setting. Only when the Enable
Fieldbus Setpoints = YES setting is initiated (e.g. by the higher-level control) will the process output
data channel be enabled again for processing.
NO
Process output data disabled.
The inverter will continue to use the last valid (frozen) process output data
for this setpoint processing until the fieldbus setpoints are activated again.
YES
Process output data enabled.
The inverter uses the process output data from the fieldbus;
Enable Factory Setting of the Fieldbus Setpoints Parameter
When the factory setting has been activated, the fieldbus parameter
570 Enable Fieldbus Setpoints
is defined as follows:
YES
Process output data enabled;
3.3.5
Scaling of the Process Data
Process data are always transmitted as hexadecimal data to facilitate their handling and processing
by the system. Parameters with the same unit of measurement are given the same scaling to allow
the setpoints and the actual values to be compared directly in the application program of the
higher-level automation unit. There are four different process data types:
- Speed [1/min]
- Relative Speed [%]
- Current [% rated current]
- Ramp [ms]
- Position [degrees].
The different control word and status word variants are coded as bit fields and will be discussed in
a separate section.
Scaling of the Speed
The
Speed Setpoint and Speed Actual Value process data are specified in the unit [1/min] and mapped
as signed values to a process data word (16-bit integer). The following table shows the scaling for
Speed process data.
Data type:
Integer 16
Resolution:
1digit = 0.2 1/min
Range:
-6553.6 ....0.....+6553.4 1/min
8000
hex
.....0.....7FFF
hex
Applies to:
actual value of speed
speed setpoint
speed limit
slip compensation
If the motor is connected correctly, positive speed values correspond to CLOCKWISE direction of
rotation or, in the case of hoisting applications, to CLOCKWISE = UP. Correspondingly negative speed
values correspond to a COUNTERCLOCKWISE (DOWN) direction of rotation and are represented as
two’s complement.
3
Inverter Control
with Process Data
MOVITRAC
®
31.. Fieldbus Unit Profile
21
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