Rockwell Automation 1760-xxxx Pico GFX-70 Controllers User Manual - Manual (Page 242)

Publication 1760-UM002B-EN-P - March 2005
4-132 Wiring with Pico GFX-70
Function of the PUT Function Block
Figure 4.57 Signal diagram of PUT function block
1: trigger coil
2: trigger coil contact feedback
3: send
Pulse Width Modulation
Pico GFX-70 provides 2 pulse width modulation function blocks PW01 and
PW02. The function blocks are connected directly to the outputs.
They are assigned as follows:
PW01 → Q1
PW02 → Q2
The pulse width modulation function block is primarily used for outputting
the manipulated variable of a PID controller. The maximum frequency is 200
kHz. This corresponds to a period duration of 5 ms. The maximum period
duration is 65.5 s.
Wiring a Pulse Width Modulation Function Block
A pulse width modulation function block is integrated in the circuit diagram as
a contact or coil.
IMPORTANT
When using the pulse width modulation function block
with a minimum on time of less than 1 s only use devices
with transistor outputs.
IMPORTANT
To prevent unpredictable switching states, use each coil of a
relay once only in the circuit diagram.
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