6. Function blocks
6.1 Manufacturer function blocks
Operating principle
You can use the pulse output function block to generate a defined number of pulses
at device output Q1 or Q2.. This series of pulses is called a pulse train. You can
change the frequency within the pulse sequence. You can generate several pulse
sequences in defined intervals. You can use these pulse trains to control a stepper
motor in the three possible individual sequences: acceleration, operation, and decel-
eration. The function block also has Jog mode as well as normal mode.
Each function block is assigned a set device output for the fast pulses:
Function block PO01: -> device output Q01
Function block PO02: -> device output Q02
The device outputs Q1 and Q2 used must not be processed again in the circuit dia-
gram. The reason for this is that the PO function blocks overwrite all other status
changes at the device outputs Q01 and Q02.
A suitable power output stage that is compatible with the stepper motor being used
is required in order to be able to drive the stepper motor.
The step information needs to be fed to the power output stage's input logic. The
input logic for both signals should be optocoupled and process an input voltage of
+24V.
The parameter definition for a stepper motor and therefore the function block largely
depends on the rated load to be moved. This defines the framework for the maximum
start and operating frequency.
The function block is active if the EN function block input is actuated. After you have
parameterized the function block, you can actuate the function block input S_. This
will start normal operation. Alternatively, you can also actuate the function block
input TP and start the function block in Jog mode.
Pulse profiles
The PO function block enables very simple pulse profiles to be generated in order to
control a stepper motor with the sequences acceleration [1], operation [2] and brak-
ing [3]. In order to do this, a PO function block supplies a user-defined number of
square wave pulses (50% relative ON duration) I1 for normal mode and P1 for jog
mode at the permanently assigned high-speed device output Q1 or Q2.
easyE402/24 MN050009ENEaton.com
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