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Step7 with PID SIMO (single input, multiple outputs)

Created by: zivk11 at: 2/20/2010 9:34 PM (8 Replies)

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2/20/2010 9:34 PM	Rate (0)
zivk11 Posts: 5 Rating: (0)	hello.. I use S-315 to run plastic Extruder There is heating zone with cooling fan to stabilize the temperature (heating and cool) I have not found PID SIMO or another solution in Step7 v5.4 There are solutions (also paid)?? Thanks. Single-Input, Multiple-Output (SIMO) Example there is a single input coming from a temperature sensor, but then two controller outputs, or actuators, being used to change the temperature. PID can output both positive and negative values, so this example uses a case structure to decide when each actuator will be used. Let’s say that output channel 1 is connected to a heater and output channel 2 connects to a fan for cooling the system. If the PID output value is positive, then we want to raise the temperature by writing the output value to the heater and turning the fan off by writing a zero to channel 2. However, if the PID output value is negative, the false case structure writes the output value to the fan, and a zero to output channel 1. This is a very common way of implementing PID with multiple outputs. Attachment 132d74b4265.gif (379 Downloads)
zivk11 Posts: 5 Rating: (0)	Last edited by: zivk11 at: 2/20/2010 11:35 PM Last edited by: zivk11 at: 2/20/2010 11:24 PM
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2/21/2010 10:07 AM	Rate (0)
Pandiani Bronze Member Joined: 10/31/2005 Last visit: 3/7/2023 Posts: 293 Rating: (29)	I believe you've got your answer [url=http://plctalk.net/qanda/showthread.php?t=53323]here![/url]
	Last edited by: Pandiani at: 2/21/2010 10:07 AM
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2/21/2010 10:54 AM	Rate (1)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 3/21/2023 Posts: 2962 Rating: (1022)	Hello zivk11 and just in case the already received answer didn't help, you basically have it already all worked out in your own ControlDiagram. Your term "SIMO" (single input, multiple output) is also known as "Split Range Controller" and the implementationis really quite simply and one exampleis as followed: Makethe MV of the your PID Block -100% to + 100%. If the MV is <=0 copy the MV value toOutput"A" and write zero to output "B" (add 100% to it to make Output "A" 0-100% if need be or take care of this with the AQ scaling). If the MV is >0 (or NOT the above) copy the MVvalue to output"B" and write zero output "A". There is really nothing more to it andyou should have hopefully no problems programmingthe above in Step 7. If you do however rather spend money and prefer to buy apre-programmed Split Range Controller Block, you can purchase the so called "Modular PID Control" software package from Siemens which has a range/wealth of Blocksas part of the package. Part number for it is 6ES7 860-1AA10-0YX0 (note that the license concept if for single use) and you can find out more about it in the manual (see link below). Modular PID Control manual I hope this helps
	Cheers fritz The advice and opinion given in this thread is that of the author and does not necessarily reflect the views of I S Systems Pty Limited. To find out how I S Systems can help you with your automation needs please visit www.issystems.com.au.
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This contribution was helpful to 3 thankful Users how come zivk11 Berg

2/21/2010 1:25 PM	Rate (0)
zivk11 Posts: 5 Rating: (0)	Thanks, What function is to work in my case?? And what parameters are required 1. Heating - with heater powered by mercury relay 2. Cooling - fan Required: PID Autotuning On / Off Output
zivk11 Posts: 5 Rating: (0)	Last edited by: zivk11 at: 2/21/2010 1:27 PM
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2/22/2010 4:44 PM	Rate (0)
zivk11 Posts: 5 Rating: (0)	Okay I started to move (I think?) I use the function FB58 With: * MV 100% to -100% * OB35 (100ms) * Various Call Options for Pulse Control (SELECT) = 0 But it created me only upward Pulse (PULSEGEN) Is there a possibility to create a pulse in both directions?
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2/22/2010 9:33 PM	Rate (0)
Pandiani Bronze Member Joined: 10/31/2005 Last visit: 3/7/2023 Posts: 293 Rating: (29)	It seems you're not using this correctly. If oyu really want to use PID block thn, I have recommended FB 42 step controller. It has UP and DOWN pulses. Equivalent to FB42 is FB59 (not FB 58) for temperature application. But I need to warn you that FB59 (as well as FB58) is maid especially for temperature application and it expects that temperature probe is directly wired to input card. Some of the PID parameters such as GAIN, Integral time constant, deadband zone and similar are internal and are not so easy to play and chanhe online as with FB42 (of course it can be done but it is not so visually accessible like with FB42). I would recommend FB42 as P only controller and then you can experiment with that. FB 59 is PI controller. But nevertheless, if you really want to use FB 59, please have a look at the attached picture. Whn SP is equal to PV there will be no pulses. If PV becomes greater than SP, then DOWN pulse will be generated. At first there will be one widepulse due to proportional gain, and then, there will be series of shorter pulses due to integral component in order to make PV equal to SP. Please have a look and study documentation. But essentially, what you need can be programmed using LAD editor without real need for PID. Hope this helps, Pandiani Attachment FB59_in_action.jpg (251 Downloads)

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2/23/2010 4:01 PM	Rate (0)
uel123 Gold Member Joined: 1/29/2006 Last visit: 3/15/2023 Posts: 438 Rating: (62)	zivk11 Thanks, What function is to work in my case?? And what parameters are required 1. Heating - with heater powered by mercury relay 2. Cooling - fan Required: PID Autotuning On / Off Output What is "mercury relay"? This term is not known to me. Is it the same as "solid state relay"? Ifthat is true, than use modul FM355-2 S Temp controller (code: 6ES7355-2SH00-0AE0; appr. 720.00 EUR in Europe....). I believe, it has everything, that you need, allready in itself, for 4 independent channels (Heating & cooling, self tuning,...). I am using this module very often in blow- moulding machines for temperature controll of multipleheating zones. Have fun! uel123

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2/24/2010 6:24 PM	Rate (0)
zivk11 Posts: 5 Rating: (0)	OK I use FB59 and working properly (I hope!) But I have 30 TC (Thermocouple Type J) 12 heating zones with heating/cooling and the others only heating to the others, I want to using FB58 (Only pulse generatorprocessed) because of strain on the CPU How to set FB58 to pulse generatorprocessed Only ?? Thanks! Attachment 1.jpg (170 Downloads)
zivk11 Posts: 5 Rating: (0)
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2/25/2010 3:46 PM	Rate (0)
zivk11 Posts: 5 Rating: (0)	Who do we need to contact to buy 2 FB functions which can control the temperature in the extruder Iin Italy. We would need phone number and e-mail address.? Two directions: Heating and Cooling WPL_CORE_HSoftware di termoregolazione per ambiente STEP7. Versione 1.6.3(H) SINGLE DIRECTION WPL_CORE_LSoftware di termoregolazione per ambiente STEP7. Versione 1.6.3(L)
zivk11 Posts: 5 Rating: (0)
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