Rockwell Automation 1760-xxxx Pico GFX-70 Controllers User Manual - Manual (Page 244)

Publication 1760-UM002B-EN-P - March 2005
4-134 Wiring with Pico GFX-70
• Analog output QA01
• Actual value
… QV> of another function block
Displaying the Parameter Set in the PARAMETERS Menu
• + Access enabled
• - Access disabled
Contacts
PW01E1 to PW02E1, the minimum on duration or the minimum off duration
was undershot.
Coils
PW01EN to PW02EN, enable coil.
Memory Requirement of the Function Block
The pulse width modulation function block requires 48 bytes of memory plus
4 bytes per constant on the function block input.
Function of the Pulse Width Modulation Function Block
The manipulated variable at function block input >SV is converted to a pulse
string with a constant period duration. The pulse width is proportional to the
manipulated variable >SV. The period duration and the minimum on duration
can be selected as required within the specified limits.
The function block causes a direct output of the pulse to the corresponding
output. The output image of the circuit diagram is always updated.
IMPORTANT
The pulse width modulation function block must be
enabled so that it can work. Coil PW..EN is active. If coil
PW..EN is not active, the entire function block is
deactivated and reset. The output value is set to zero.
IMPORTANT
The following applies if the output of a pulse width
modulator is used as a coil in the circuit diagram:
The state of the output is not refreshed from the circuit
diagram.