S7-300 with Micromaster 440

Hi friend, How to write a logic to control Micomaster440 with USS communication using S7-300 PLC.
I want a standard program to simulate it.

Hi Arun.

Not exactly an answer to your question, but I think that to control a MM via USS from an S7-300 is not a good idea.

To achieve USS from an S7-300 you would have to add an expensive CP341 with loadable drivers. And it would require a bit of programming that you would have to figure out yourself. I cannot locate ANY sample projects with USS protocol on Siemens support site, only manuals.

Profibus is a much better solution. The Profibus slave card for the MM is surprisingly low priced (approx 150 Euro).
Maybe your S7-300 has a Profibus port allready.
And if you go this way, then there is a very comprehensive sample project on Siemens support site.

Thanks Jesper

I am studing a PLC program for already configured five drives and and one drive has a problem and I replaced it and set all parameter but unable to configure as original so I want to study the sample project to get idea.

I have programmed and configured a project using USS between a S7-314C-2Ptp and a MicroMaster 420 drive. I agree with Jesper, use Profibus - it is worth the spending the money for the Profibus drive adapter rather than the time to get USS to work.

But, apparently you have a machine that is already configured. If you had to replace a drive, then take a look at the following drive parameters. They configure the drive to communicate on the USS network.
P2010 - USS Baud Rate
P2011 - USS Address
P2012 - USS PZD Length
P2013 - USS PKW Length
P2014 - USS Telegram Off Time
If all five of your drives are on the same network, each one was originally configured with a unique address (P2011). You need to make sure the address of the new drive has the same address as the one you removed.

You should also note that each these parameters has two indices: [0] is for the COM link and [1] for the BOP link. You should check both.

Jesper,

I agree, profibus is much better BUT,
Actually it is pretty common and you dont need a CP341 with any loadable drivers- a CP340 with the DriveES Simatic blocks- called "USSS7" works very well. It is basically a send block and receive block. If anyone needs a manual- let me know.

JRW said:

I agree, profibus is much better BUT,
Actually it is pretty common and you dont need a CP341 with any loadable drivers- a CP340 with the DriveES Simatic blocks- called "USSS7" works very well. It is basically a send block and receive block.

Click to expand...

Aha, I did not know that. The CP340 only supports ASCII and 3964R. I guess then that the USS protocol is realised in STEP7 code and ASCII mode.
I also didnt think about the onboard port on the 314C-2PtP.

are the loadable drives available for free or i need to buy them

hi,

as you said you have configured the drives Micromaster 420. I want to know about parameter 2009 and 2014. Total 5 drives and out of them one is not working which i have replaced. I cheched all parameter OK addresses are different for each drive, Baud rate and other parameter are same. Also I doesn't found terminating resistor so I put the terminiateing resister.

Parameter 2009 is the "USS Normalization" which just defines whether the set point is normalized (0-100%) or absolute (168 Hz). Parameter 2014 is the time before a fault is generated. I do not think these parameters will cause a problem. Are you getting a drive error or fault?

If your new drive has the same parameter values as the old drive, then communications should work - at least the parameters should be correct. Therefore, it may be something else.

Can you force the drive to move its motor? What are you using to check the parameters: BOP, AOP, PC with Starter? If you have one of these, you should be able to manual command the drive.

I am using BOP to check the parameter. And I am now confused that this drive is added later and has some bug in program. I have interchange the drive and found working OK. To understand it I need sample program. If you have please send me.

If you work often with MicroMasters, then it is a good idea to invest in the serial PC connection kit. It is not expensive.
You can upload from a drive, and then compare all parameters much more easily than with just the BOP.

Attached here (hopefully) are the parameters from a MM420 drive connected to a S7-314C-2PtP. This is the complete list as printed from Starter.

Here are links to Starter and the MM440 Parameter List Manual in case you need them.
Starter (Entry ID 23036126)
MM440 Parameter List (Entry ID 23708204)

Here is a link to a Siemens manual for using the USS protocol with a MicroMaster 420.
Using USS Protocol with MM420 (Entry ID 5734889)

Out of curiosity, what control hardware (which S7) and communications modules (PtP, CP340, CP341) are you using?

Also, I do not think I understand the problem you are having. I understand that you have a machine with 5 MM440 drives. But one of those five drives stopped working for some reason. So you removed that drive and put a new drive in its place (so you still only have 5 drives). But that new drive will not work either. Is this correct?

What was wrong with the original MM440? Did a fault or alarm appear on the BOP?

What is wrong with the new MM440? Does the BOP display a fault or alarm?

Original 440 drive is burnt totally dead so display on BOP.
Originally we have four drive on machine as per requirement we install new pump and so one more drive as added.And all wiring and programming is done by machine manufacturer only but our mistake is no one look at his work and till drive fail we think it is previously working ok but this is not like this because when we check for PLC program found lots of mistake and as we are maintenace people no one of us know details how to configure the drive and now machine manufacturer doesn't locate his programmer also. He left the job.

Thanks in advance to all

I am not sure I know how to help you.

If you are concentrating on the PLC program, you have not told us what hardware you are using. I gave you a link for a S7300. The Siemens web site has information for using the S7-200 with MM440 over USS. What PLC are you using? Are you using a communications module or a PLC with PtP?

Or, do you need help commissioning and configuring your MM440 drive? Here is the MM440 Operating Instructions manual (Entry ID 21741842)

I suggest you get some on site help from the manufacturer or Siemens.