11/17/2018 9:42 PM | |
Posts: 2826 Rating: (685) |
Hello. Slow analog processes for example can make use of multiplexer circuits to reduce the analog input count. Other times pre-processing can be done with micro-controller boards. Just take this beauty for an example: (https://www.parallax.com/product/32123)
Foundation Fieldbus comes into mind when thinking of a protocol that has embraced distributed control
Another spin or two to this one - Working with the S7-1500 (and owning the software) may open some other doors for you. (Convince Siemens of this fact too!) The S7-300 (with classic Step7) is also an option, but the density ability is not huge. |
Last edited by: #dP at: 11/17/2018 9:46:30 PM |
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11/17/2018 10:45 PM | |
Joined: 8/15/2015 Last visit: 8/21/2024 Posts: 133 Rating: (4) |
Dear Mr.#dp The system consists without going into too much detail for a sake of time
-4 X 3-phace turbines each with a flow switch and redundancy -10 pneumatically controlled valves -a bank of 20 Tones ( 20 000L ) with several level sensors (digital , and several redundant analogue pressure transducers ) -air compressor ( with analogue Pressure transducer , and a future digital pressure switch ) -an other 2 000L tank that also has Redundant level sensors and an analogue pressure transducer -all of these systems must work on timers , to start in sequence to produce work and to stop in sequence and several feedback loops to stop the waste of energy Regarding points : point 1 - clear ( For these engineering tasks that have a lot of RFI (3 phase power everywhere ), and magnetic interference Arduinos and small micro-controllers don't seem to survive + very unreliable point 2 - I've selected the "ET200" for the sole reason that can have a lot of I/O and nothing else , note that I didn't bought anything yet until i get to a proper working solution , Regarding the ASI that would be nice in order to cut down on most inputs and outputs that consists of the user interface on the panel ( I also considered to used an HMI , but in the environment that will be installed I do not trust a monitor that could cost the price of 4 expansion modules for I/O) but the price goes up as well for little to none return because if a button or a lamp breaks you need to by the specific part that is not considered jellybean part like a panel mount pushbutton that you can find anywhere ( even the cheapest brand at a local electrical supply store ,plus any electrician can replace that with half a brain(not that I mean electricians don't have brains but someone with the most basic of knowledge can ) point 3 - due to the fact that everything must be executed in order both in shutdown and startup if one module goes down the result of the proses is paralyzed (and without the user noticing its effect quickly so is like taking the whole system offline therefore is not a big deal for me to take the whole system down for maintenance or testing or what not but nonetheless some less important parts can be separated from the main system that are complete supportive subroutines with no ripple effects on the rest of the system Point 4: Not a Chance to have a subscription based lissince because 1 : the development and integration of the system may be stepwise and not all at once , 2: It's pointless and i find it to be counter-intuitive 3: I may need to change some aspects of the system in 2 years , or 2 weeks I should buy the license 4 times ? not really 4: I am the client :D 5:
What do you exactly mean by that ? and I didn't deal with siemeds sales directly but rather with a local reseller so I don't think he is going to care or be able to give me a better deal rather than the typical on paper price :'( regarding the S7-300 the idea is to move forward not backwards If i will spend a certain amount i rather do it with the latest of the time hardwear S7-300 is being around for quite some time and the price didn't really change since then so i wouldn't go towards it for several reasons
Fortunately yes but I like their reliability , name brand , and that I've tested them quite extensively plus due to their popularity servers open source stuff exist like ( step7 library for Raspberries , arduinos , and so forth ) but if they seem out of my league with another company willing to provide the goods i need at a lower price of course I will go ahead and go with that although do some testing first
The fun fact, I am a medical student :D and this is my "Hobby" :D expensive but very enjoyable Thank you very very much for all the insights and help , now I hope Siemens will get in contact (i've emailed them :D ) Thank you in advance Le Test !!
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