[FailerJerry]

1. First of all what hardware of Siemens do I need to build the entire controller? I have been reading through everything and kind make it up, sorry if that seems stupid but I am really not.

2. I don't want a screen at the machine, just a computer so how does that work with the sinumerik?

3. What control software should be on the computer to communicate with the sinumerik 840d sl
(Ref to mach3 and Mach3 breakout board for simplicity)

4. What's the deal with the basic packet: sinumerik 840d SL + sinamics120 . Says there can drive up to 6 axis. So how does this connect? I can throwout my leadshine drivers and connect servo to this hardware?

5. Would this packet be enough as controller and drivers of motors? Can the rest be handled by my own PC and 3rd party servo motors?

Hi there,

I'll try to share some info from my own experience. I have built some odd custom machines with Siemens hardware, so I can't speak to how to do this for specifically a mill or lathe, but others have posted about the mechanical and stability/hardware requirements.

1. To address the hardware, the 840d sl is an entire package. I am sure you can part out the items you want. The HMI with associated hardware buttons, as well as the typical control panel (another bank of buttons) are nice to have but not essential. Here is my list of minimums:

AC Portion:

You will need at minimum a line filter and a line reactor + fused protection on mains.

DC Portion: Any 24VDC will work with enough current capacity to handle whatever IO you have and what the NCU requires. 10amp should be sufficient for most machines. Maybe 5 if your IO is small.

Controller Portion:
You will need at minimum:
A Line Module. Comes in 3 flavors, basic, smart and active. This takes in the 3 phase AC, rectifices to 600VDC and is then fed to the motor modules who PWM it out to the motors per phase. Or something. You need one though.

The NCU itself. This will contain a 300 series PLC, the NCU, and a bunch of other integrated electronics, HMI code, etc etc etc.

Then 2 DMMs, or Dual Motor Modules (for six axes total) and a single motor module.

So that is AC filtering/reactor, DC Converter, Line Module, NCU, and Motor Modules. Take a look at this recommended topography. Also here is a graphic of the product overview for hardware. Not you do not need everything in here...just what I have mentioned for one way to set it up.

2. The HMI they offer is nice to have as it has many premapped buttons for machine functionality that you might not be aware of without years of digging through their manuals on what you CAN do in terms of HMI. Luckily they main HMI program is stored in the NCU and not actually on the small computer on the back of the HMI (a PCU or TCU).

You have a number of network ports on the NCU (cat 5 or profinet). They are for the profinet network (x2), HMI/control surface network, "Company Network", and Service port. On the service port you can upload PLC / HMI programs. You can write these in whatever you want...I think the software to use / alter Siemens screens is called "My HMI Screens" or something horrible. Call your disti and ask for details about software for HMI Operate screen manipulation. Alternatively you can write whatever application you want and have it communicate over OPC UA to swap data structs back and forth. It is a pretty easy pipe to open, I use s7.net and it works great. The hard part is really reingineering what the 840D system is meant to do out of the box without the benefit of knowing it. There are dozens of thousands of paramterized variables that you will have access to. If you are a great manual mole, go ahead...but I sure would dread that task. Other options like Labview are also an option. My opinion here is, you are already paying for all the HMI code and functionality when you buy the NCU. Why not use it? Any HMI that is profinet capable should work to display output that is already stored from the factory.

3. As mentioned above, you can just use any old PC, or really even an arduino. s7.net is a great toolkit to open a pipe and a network cable to x127 or x130 (ncu ports). Then you can just read/write to anywhere with direct addressing, and inderect with a little more effort. I've never seen a mach3, but it looks like a really cheap tiny thing that does something vaguely similar to an 840d. You can just plug your laptop into the 840 and program it with Step7, and once the PLC is programmed and everything is commissioned, bash bits around like crazy with a couple lines of C#.

4. The Sinumerik is the control Unit portion of the S120 system. Here is the sort of product map. The motor drive modules have a few connection points. 5 wired AC outputs out of the bottom, 600VDC rails strapped across the front, some 24VDC electronic supplys, and a bunch of CAT5 ports up top that siemens refers to as "Drive Cliq". Basically you jumper coms back to the NCU with them, and plug the motor encoder as well (there is no back plane attachments). In addition a few ports for enable / inhibit bits for each motor module (2 per rack unit). Again, the PLC is integrated into the NCU, so to do useful stuff, you plug into the NCU over cat5, program the PLC / HMI with Step 7. Everything else regarding comissioning / setup / operation can be done from the provided HMI screens. There is free software that you can grab that will bring up what the HMI is doing inside a regular windows screen with just the IP address of the NCU (which is its own DHCP server that you will be a client of when plugged in).

5. Yes. You will likely need to terminate your own ends. The output power from the motor module have a specific connector that you can order from them stand alone or prewired with a non terminated end. The encoder cable goes into the control with profinet which is like a 4 wire cat 5 looking thing. You can use regular cat 5 though. That part on correctly terminating all your ends depending on what servo motors you use may be a bit of a pain to get correct.

Additional: IF there is any IO in the system that is not strictly a motor (limit switches for example, or e-stops, etc) then you will need some form of IO block. For siemens this is the ET200 series of profinet/bus modules.

PS: Getting a step 7 license will be required if you need to program the PLC to do anything interesting I think. I don't really know what they do out of the box with zero PLC code. They'll do basic CNC type stuff, but again see note on IO or file handling, etc etc. At a bare minimum you will have to commission them, which means using step 7 to correctly configure the hardware / firmware / IP addresses and device names.

PPS: Depending on what you want to do, as others have mentioned there maybe additional licenses you need. Normally if you try to do something you are not licensed to do, it will tell you what you are missing license wise. You can also just turn those licenses on in an HMI screen and a 1 hour annoyance message will tell you a license is missing but it will work indefinitely on machines prior to rev 4.4.


Most of the images and references are from the following manual number on the Siemens website: 6SL3097-4AH00-0BP5