5 Function blocks
5.25 PO, pulse output
234
Control Relay easy800
11/11 MN04902001Z-EN
www.eaton.com
Figure 167:PO pulse output - jog mode
FS = Start frequency
PF = Jog frequency
A = Number of pulses at TP on time < 0.5 s
B = Number of pulses at TP on time > 0.5 s
E = Braking phase
If a very small number of pulses are set, the start pulse at the TP input also
has to be very short. Otherwise the function block will output several pulse
sequences (see range A Figure 166).
Application
The function block is often used in order to control a stepper motor via a
power amplifier. The motor converts pulse sequences into steps. The
number of pulses therefore determines the travel distance. The frequency of
the pulses determines the speed of travel. The travel behavior of a stepper
motor in Normal mode can be divided up into three phases, which the PO
function block supports with variable frequencies:
•
Acceleration: Frequency increase that the motor converts into
acceleration; starting from a starting frequency up to operating frequency
•
Operation: constant operating frequency
•
Braking: Frequency reduction that the motor converts into braking;
starting from the operating frequency down to the starting frequency
If you require a direction signal for bidirectional stepper motors, use one of
the other device outputs.
Jog mode is often used to set up an installation.
Memory
96 + per
4 Byte/Constant at function block input
A
B
E
Q1/2
AC
EN
PF
FS
TP
≦ 0.5 s
≦ 0.5 s
0.5 s
