Siemens equivalent to a MicroLogix 1400?

I'm having to make a rush quote on a project. It looks like a relatively simple process- something I would normally use a MicroLogix 1400 for. But the customer spec calls for a Siemens PLC.

Can anybody point me in the right direction for a Siemens PLC that could accomplish basic tasks such as PID and high speed outputs- basically the equivalent of a ML1400? There will be a pump, a few valves, and PWM control of a heater.

Thanks!

S7-1200.

1214 for few extra inputs/outputs etc...

Thanks! Actually I am now told that it needs to be an S7 300 series- any advice on which model 300 to go with for a relatively simple process? I see there's limits on speed, memory, etc depending on the model. Again, thanks for the help!

agree with m_turk, the S7-1200 family is probably the best answer. You'd need to chat with your local Siemens distributor about IO counts to see which model would suit you best.

However, you may need to check with your customer if they have a software requirement. Many plants use the older version of the programming software (Simatic Manager, or Step 7 v5.5). This software doesn't support the newer PLC families, like the 1200. The newer software is TIA Portal, and would be between V10-V13.

If they do require the older software, then the S7-300 family has some compact CPUs (313C, etc) that have onboard high speed IO that would meet the requirements as well, but at a higher price.

Edit: I see you posted that do require an S7-300 family, right as I posted the above. You probably only need one of the smaller ones (312 or 313), but make sure you get one of the compact cpus with the included IO. You save money on the a few expansion cards, and it's the only simple way to get high speed IO.

Awesome- thanks so much. So those smaller ones sound much like the ML1400 if it has I/O on the base module. It looks like the latest software is Step 7 v7.0. Do you have any rough ideas on what the cost of one of the lower end 300 series + a few analog modules would be? I'm assuming the software cost and capability is roughly the same as RSL5000?

Yeah.. I see that a lot.. S7-300 for the simplest project so you get a plc 2x price and 0.5x strength...

I like the s7-300, but not the slow ones and not for simple projects...

I would ask for a quote of the 2 systems including everything you need comparing the s7-300 with all hardware vs the s7-1200 with all hardware (including starting kit to get the software license).

Then present the 2 quotes to your client. Also programming using tia portal is a lot more user friendly. Unless you have a really good reason to use a 300 series for this project. I had a quick look at some of the prices I found and it is about half the price as m_turk said.

Are you saying the 1200 is about half the price of the 300? And the programming software is better? Hmmm

rupej said:

Awesome- thanks so much. So those smaller ones sound much like the ML1400 if it has I/O on the base module. It looks like the latest software is Step 7 v7.0. Do you have any rough ideas on what the cost of one of the lower end 300 series + a few analog modules would be? I'm assuming the software cost and capability is roughly the same as RSL5000?

Click to expand...

Not sure on the pricing of the lower end stuff. When I use S7-300s, its the higher end processors, 315 and up.

The most recent version is S7 v5.5, for the old style software. There is no v7, although it does run on Windows 7.

Cost and capabilty of a 312-313 are probably in the range of a upper level compactlogix or lower end controllogix. The "compact" versions of them are a bit different in form factor than an ML1400 or S71200. Think of a 313C more like an L5x CPU with 2-3 IO modules glued to the side. You can expand more from there as you need to, but it comes with a few IO modules literally built in. See pic below.

http://www.hmkdirect.com/images/products_shop/P_ST70_XX_05797J.jpg/rs-500x300a.jpg

The downside of the S7-300 family is that the programming is a bit old fashioned, and the capabilities of LAD are a little limited in comparison to modern platforms. As an example, you can't do indirect addressing of arrays in LAD in an S7-300, you need to either do that in SCL/ST, or you need to use pointers in STL (basically assembly languauge). It does have other ways in which it is more advanced, with very modular code and ways to make HW diagnostic messages for the whole system in seconds.

The 1200 platform hardware will be more cost effective, and the engineering of the newer 1200/1500 families is much more friendly/efficient, especially someone coming from a Rockwell background.

Thanks so much for explaining all of that- this is all new to me so the guidance is much appreciated. I'll see if the customer has any flexibility to move towards the 1200. I'd hate to make my first step into Siemens be in the wrong direction.

If you are going with the 300 series I would recommend a im151-8 for simple instalations. (Though et200s is techinacly not a 300 series the cpu functions the same as a low end 300)

The reason some companies use S7-300 series instead of the newer ones is because all the bugs and problems in the TIA software. And reliability is often preferred over bells and whistles.

mk42 said:

The downside of the S7-300 family is that the programming is a bit old fashioned, and the capabilities of LAD are a little limited in comparison to modern platforms. As an example, you can't do indirect addressing of arrays in LAD in an S7-300, you need to either do that in SCL/ST, or you need to use pointers in STL (basically assembly languauge).

Click to expand...

Ladder in S7-300 is not old fashioned, it's just not good.

I worked with PLC's from the 80s that can do indirect addressing and lots of other stuff in ladder that the S7-300 cannot.

Sometimes I wonder what rookies Siemens uses in their development teams.

For the 1200 series you can only use step 7 in Tia Portal.
For the 300 series you can choose between the old simatic step7 or the new step 7 in tia portal.

The newest version of Tia portal is stable on windows 7. But it is SLOW, a lot slower than the older software.

Here is a comparision from some prices I found online:

6ES73125BF040AB0 CPU 312C COMPACT CPU WITH MPI, 10 DI/6 DO, 2 FAST COUNTERS (10 KHZ), INTEGRATED 24V DC POWER SUPPLY 429 euros

6ES72141BG400XB0 CPU 1214C, COMPACT CPU, AC/DC/RLY, ONBOARD I/O: 14 DI 24V DC; 10 DO RELAY 2A; 2 AI 0 - 10 326 euros


Actual prices from my local supplier for different products from that list were about 20% less.