Motorized Potentiometer Function via Fieldbus
Fieldbus control of the motorized potentiometer setpoint function works the same as control via the
standard input terminals. Set parameter
P150 Motorized Potentiometer = YES to activate the
motorized potentiometer function. In this case a speed setpoint which might be specified via another
process data word will no longer be considered.
To change the setpoint, use the two control word bits
Motorized Potentiometer Up (bit 9) and
Motorized Potentiometer Down (bit 10). Operating bit 9 Motorized Potentiometer Up will increase
the setpoint, bit 10
Motorized Potentiometer Down will decrease the setpoint.
The direction of rotation is specified by bit 8
Direction of Rotation in the control word. Direction of
Rotation = 0 specifies clockwise direction of rotation, Direction of Rotation = 1 counterclockwise
direction of rotation.
The process ramp which may be specified via another process output data word has no effect on the
motorized potentiometer function. Only the motorized potentiometer ramp generators
P151
T4 Ramp Up
P152
T4 Ramp Down
are used.
Internal fixed setpoints
Selection of the internal fixed setpoints via the fieldbus interface is the same as via the standard input
terminals. To select the internal fixed setpoints use bit 11 and bit 12 of the control word respectively.
The following table shows how the internal fixed setpoints are selected depending on the chosen
parameter set.
Par. set
Bit 12
Bit 11
Active setpoint
Internally stored fixed setpoint parameter
1
0
0
Speed setpoint via fieldbus
–
0
1
Internal fixed setpoint n11
P160
N1
1
0
Internal fixed setpoint n12
P161
N1
1
1
Internal fixed setpoint n13
P162
N1
2
*)
0
0
Speed setpoint via fieldbus
–
0
1
Internal fixed setpoint n21
P170
N21
1
0
Internal fixed setpoint n22
P171
N22
1
1
Internal fixed setpoint n23
P173
N23
*)
Parameter set 2 not available for MOVITRAC
®
31.., size 0
When an internal fixed setpoint is selected, the direction of rotation is determined by control word
bit 8
Direction of Rotation. The process ramp which might be specified via the fieldbus has no effect
when the internal setpoints are used.
Inverter Control
with Process Data
3
30
MOVITRAC
®
31.. Fieldbus Unit Profile
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