alpha mitsubishi or logo siemens? Or..

[Gianni86]

Hello everybody, I have been looking on possible solutions for a simple conveyor controller that our industrial partner wants to build. I have found it really interesting to look for information but I realise that a second opinion from an experienced user would be very valuable. I will program the control and I will be using two through beam sensors, one reflective and two inductive proximity, I will also be using 5 manual switches.From the output side, I will need 3 relay outputs to energize respective contactor coils which will in turn allow 3 three-phase motors to run, and I will also use some alarm indicators.
The first PLC I was looking at is a2 series from mitsubishi. However, I saw today that LOGO could be handy as well, plus it has a programmable text display. I would choose one of the two because they use programmable function blocks which at a first glance seems easier.. also because I'm usually working with Labview.. but I would not say no to another solution. I have only done theoretically ladder when I was an undergraduate though. Another thing that I'm concerned about is the programming memory of both mitsi and siemens. Is it enough for a small application like this? Thirdly, it seems that there's more info about logo on the web. What do you think? Regards

Giovanni

 

[TurpoUrpo]

I dont know what is your budget. But, i myself would not touch either of them (have never used alpha, but logo i have, alpha looks like same scheisse). S7-1200 could be option, depends really on budget..

 

[Zane_Terblanche]

I second turpos opinion and option

 

[PeterW]

Should be pointed out that a LOGO is not a PLC, its known as an intelligent relay.

 

[zova]

These products are functionally identical. I have dealt with all of them. I guess your choice should be based on availability at the nearest dealer.

PS. Time of delivery of Zelio to my location takes less two weeks, if it isn't at dealer's warehouse. Mitsi and Siemens 4-8 weeks.

 

[Gianni86]

Thank you guys. Would you mind though sharing what led you to this conclusion? I suppose that you imply such units cannot stand for high end applications. On another note, I should have told you that I am considering such solutions because this system will serve as a test one, this meaning that it will not be used for more than one year. Therefore,indeed, budget is limited.

 

[OkiePC]

...indeed, budget is limited.

http://www.aboutplcs.com/click/

 

[Zane_Terblanche]

You might be surprised by how expandable the LOGO is. For me it has just been my own experience with them that has led me to prefer not using them. I am a siemens fan but I had so many connection issues with the LOGOs via USB that eventually I couldnt stand it.

 

[ivo.maenen]

I have worked with the Alpha and I would not use it if I had the choice. The reason is the programming-software. I also used Logo, only for a limited time, but the software was better.


Both Alpha and Logo are intelligent relays.

 

[Daye.04]

Do correct me if I'm wrong, but won't a S7-1200 be a bit overkill for such an application. To me it sounds like all OP really need is indeed an intelligent relay. And while I haven't tried either Logo or Alpha, I have tried Zelio and Easy. I think both of them works quite nicely for small applications, and both may come with screen and buttons to program on if desireable.

Personally I like Zelio the best, since it has the possibility of programming in Function Blocks. Whereas Easy only uses ladder

 

[adfox]

Decision is simple: How many I/O You'll need ?
Will the process be complex and You'll have to change the program multiple times during start-up ?

If you want simple start/stop go for Logo. If You'll need editing in run and complex logic - take S7-1200. I did once "simple 8 motors sequence" on Logo.

Client insisted on taking Logo instead of 1200. It was tragic.
As soon as the logic grow bigger - he was amazed i could find myself on 3 pages of connections ( a week later i couln't get how it works at first glance).

Also stopping the controller to download small change was very annoying.
From that moment I can tell You that I will take Logo but only for switching lights in my home and simple things - not to do industrial stuff.

 

[Bit_Bucket_07]

http://www.automationdirect.com/adc/Shopping/Catalog/Programmable_Controllers

Direct Logic and Click series are inexpensive and the programming software is a free download.

Need an inexpensive HMI to go with it? Software is free for these also.

http://www.automationdirect.com/adc...-Graphic_Panels/6_inch_Panels_-a-_Accessories

 

[TurpoUrpo]

Decision is simple: How many I/O You'll need ?
Will the process be complex and You'll have to change the program multiple times during start-up ?

If you want simple start/stop go for Logo. If You'll need editing in run and complex logic - take S7-1200. I did once "simple 8 motors sequence" on Logo.

Client insisted on taking Logo instead of 1200. It was tragic.
As soon as the logic grow bigger - he was amazed i could find myself on 3 pages of connections ( a week later i couln't get how it works at first glance).

Also stopping the controller to download small change was very annoying.
From that moment I can tell You that I will take Logo but only for switching lights in my home and simple things - not to do industrial stuff.

This.

I cant really begin to describe how totally awful logo programming is, even "simple" works needs awful spaghetti code.

Smallest S7-1200 costs here like 120€ it has few integrated io etc. So its not like its overkill for small application.

Logo is so big pain to do anything with, that it pays in work time to use s7-1200 many times over any cost saving there is for logo..

 

[SteinCollector]

Hi Gianni

I have never used the logo, so I can't comment. I've used the Alpha, the Easy (Eaton), and the ZEN (Omron). I don't understand the negative comments from above - I've had good experiences. Of the 3, I prefer the Alpha, the graphical function block software was easy to use and understand in my opinion.

 

[Gianni86]

Hmmm,first of all thanks to all of you for your comments. There is more to look into now, i.e. Zelio, S7-1200, Click by Koyo, Easy, Direct logic, Zen…oh well… It is going to be an interesting day!!Thanks to all of you again. Regards.
Giovanni