Fixed Speed As Setpoint Source - Siemens SINAMICS G120 Operating Instructions Manual

Functions
8.4 Setpoint sources
8.4.3

Fixed speed as setpoint source

In many applications after switching on the motor, all that is needed is to run the motor at a
constant speed or to switch between different speeds. Examples of this simplified
specification of speed setpoint are:
● Conveyor belt with two different speeds.
● Grinding machine with different speeds corresponding to the diameter of the grinding
If you use the technology controller in the inverter, then you can enter process variables that
remain constant over time using a fixed setpoint, e.g.:
● Closed-loop control of a constant flow with a pump.
● Closed-loop control of a constant temperature using a fan.
Procedure
You can set up to 16 various fixed setpoints and select these either via digital inputs or the
fieldbus. The fixed setpoints are defined using parameters p1001 to p1004 and can be
assigned to the corresponding command sources (e.g. the digital inputs) using parameters
p1020 to p1023.
The various fixed setpoints can be selected in two ways:
1. Direct selection:
2. Binary selection:
176
wheel.
Precisely one fixed speed setpoint is assigned to each selection signal (e.g. a digital
input). As several selection signals are selected, the associated fixed speed setpoints are
added together to from a total setpoint.
Direct selection is particularly well suited to controlling the motor using the inverter's
digital inputs.
Precisely one fixed speed setpoint is assigned to each possible combination of selection
signals.
Binary selection should preferably be used with a central control and when linking the
inverter to a fieldbus.
Operating Instructions, 01/2011, FW 4.4, A5E02999804A AB
SINAMICS G120C Inverter