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I'm trying to get an PWM output from a PLC S7-1200 with CPU 1214C

Created by: Miguel Silva at: 4/21/2014 7:56 PM (4 Replies)

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4/21/2014 7:56 PM	Rate (0)
Miguel Silva Posts: 3 Rating: (0)	Hi, I'm a student from Brazil, electric engeneering. I'm trying to get an PWM output from a PLC S7-1200 with CPU 1214C ac/dc/rly. When I enable the pulse generator Pulse_1 and I compile the programme I get following error: ,Enable this pulse generator: Pulse outputs cannot be used for integrated relay outputs. But I definitely did enabled this generator and already followed your example but even then I get the same error.
Miguel Silva Posts: 3 Rating: (0)	Last edited by: GrasserF at: 4/22/2014 11:37 AM new subject after splitting from /tf/WW/en/Posts/52823#top
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4/21/2014 8:26 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 12/23/2024 Posts: 15531 Rating: (2461)	Miguel Silva Hi, I'm a student from Brazil, electric engeneering. I'm trying to get an PWM output from a PLC S7-1200 with CPU 1214C ac/dc/rly. When I enable the pulse generator Pulse_1 and I compile the programme I get following error: ,Enable this pulse generator: Pulse outputs cannot be used for integrated relay outputs. But I definitely did enabled this generator and already followed your example but even then I get the same error. PWM is only available for PLCs with xx/DC/DC (AC/DC/DC or DC/DC/DC). Physical relays will not switch fast enough to control within the plc's pwm capabilities. Onlytransistor outputs can react quickly enough (since they do not have anything physical to move through the air to allow current to flow).
	science guy
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4/21/2014 9:09 PM	Rate (0)
Miguel Silva Posts: 3 Rating: (0)	How then simulate PWM in this situation?
Miguel Silva Posts: 3 Rating: (0)
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4/21/2014 10:29 PM	Rate (0)
0_Einstein Diamond Expert Joined: 7/7/2010 Last visit: 12/23/2024 Posts: 15531 Rating: (2461)	Miguel Silva How then simulate PWM in this situation? If you add a DC digital output signal board to the plc, you should be able to PWM that output, though I have read others have had difficulty convincing the portal to activate the pwm option with certain versions of portal/plc firmware. If you are being expected to perform PWM control using a relay output, you can always write up the reasons why the provided hardware is utterly incapable of lasting the required time to develop, test, and operate the relay enough times to simulate even a very slow PWM control output, and then write the logic for the right plc and see if that is accepted. Another approach might be to use an analog output, and a digital output or 2 or 3 etc along with some external circuitry to perform the PWM control. If you want to simulate, you need s7-1500, -300/-400 PLC software which includes PLCSIM as part of the professional portal package. This is now beyond the scope of the original posted questions in this thread: /tf/WW/en/Posts/107010#top
	science guy
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4/21/2014 10:59 PM	Rate (0)
Miguel Silva Posts: 3 Rating: (0)	Thanks for help huggy_d1 !!! I will emulate a PWM generator with a normal program without the help of special digital output of the CPU.
Miguel Silva Posts: 3 Rating: (0)
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