Siemens Classic Step 7- CPU 319-3 Upload Options

I've been working for a customer with Siemens Step 7 (classic) PLC automation, using a Siemens Field Service Laptop, and V5.6 of Simatic Manager. I've been slowly building my Siemens knowledge, but I've got a basic question to ask...

There is a Siemens PLC that used to control a side-process in the plant, but has been mostly replaced by a Modicon PLC, controlled by a 3rd party and which I have no access to the program. I suspect that the Siemens PLC is still being used to receive input from the DP/AS-i Link I/O modules, then give manual control commands (versus "Auto Mode") to the Modicon through digital output cards on the rack, but I can't stop running the program to hook up or test what I suspect is happening. There is a possible program in the PLC that might be for that process, but I would have to hook up to the PLC and check it without turning anything off. I'm a little fuzzy on the difference between the different interfaces on this PLC: MPI/DP, versus DP, versus PN (Lan), (Profinet, I assume). Am I able to upload the program from any one of the interfaces?? I usually use DP, but I'd have to unplug that and put the piggy-back plug in first. Any insight on how I should connect the PC to the PLC, and which driver to select?

PN is Profinet which is Ethernet; that's almost certainly the easiest way to go.


MPI is MultiPoint Interface, which is more or less a predecessor of Profibus DP.

Yep the PN port is the way to go.

You can use Simatic Manager to find the IP address, if it has one, or change it,

Hmmm... Using the Profinet through the P1 Ethernet port, I can access other addresses in the system. (I'm assuming the Profibus cable is providing the pathway.) But, I can't see the node of the PLC I'm attached to.

I was correct in assuming the Siemens PLC is only there to act as a bridge between the AS-i inputs, such as push buttons and limit switches, and the hard-wire inputs of the new Modicon PLC. So... I don't *need* the program to go online, now that I have the blocks and the output addresses mapped. I can pretty much look at the output LEDs to see the status of different inputs. But I'll try another route sometime when the process is not active, and I can unplug the DP Purple Hose without affecting anything. Then, I'll piggy back it on my communication purple hose.

AutomationTechBrian said:

Hmmm... Using the Profinet through the P1 Ethernet port, I can access other addresses in the system. (I'm assuming the Profibus cable is providing the pathway.) But, I can't see the node of the PLC I'm attached to.

Click to expand...

Which other addresses are you referring to. In the photo nothing is attached to the ethernet ports.
Can you post a screenshot of what you are doing ?

The whole thing is odd. Using a potent 319 CPU merely as an AS-I gateway. I dont exactly understand the setup, how the data between Modicon and the AS-I devices are transferred via the 319.

I suggest that you start a new empty project in Simatic Manager, then use the Upload Station to PG function. Specify Rack=0, Slot=2 and let the function scan for available nodes. Maybe either a MAC address or IP address is found and a device type S7-300 CPU. If MAC address, you should be able to start the upload directly. If IP address, you need ensure that your PC is in the same subnet and then repeat the upload attempt.
If the above fails, you can try again, but via the MPI/DP port instead.

JesperMP said:

The whole thing is odd. Using a potent 319 CPU merely as an AS-I gateway. I dont exactly understand the setup, how the data between Modicon and the AS-I devices are transferred via the 319.

Click to expand...

Ok, I finally got back to this. The 319 used to be the PLC running a cement batch mixer, but the company brought in a new system and integrated it into their existing system of sensors and switches, which were already hooked up to the AS-i system. The new PLCs (2 Modicon) are in a panel about 2 feet away from the old panel. So, instead of re-wiring everything, they just used the 319 to relay the I/O from the AS-i to the new panel. Yes, it is a waste of power, but they don't need the 319 for anything, so why not use it?

I have some Siemens instructional videos to learn some of the basic tasks, one of which is to upload from the MPI/DP port. That was successful, and I've been thinking about different ways to monitor some intermittent switches that are on the AS-i network, but are not used in the PLC. They are safety inputs, so they are normally high. One of them is causing a skip-hoist to stop mid-cycle now and then, but I can't tell which one. So I'm thinking about creating a latching bit for each of the switches, and have them automatically reset themselves after 10 minutes or so. Then, I'll just look for a couple of unused outputs on a DO card to display which switch is caused tripped the safety.

I have so many things I need to learn with this Step 7 classic software. I want to ask you folks a hundred questions, but know I should work through my video tutorials first. Most of all, the STL programs are still hard for me to work with. ...And my customer's "hoist robot" is programmed all in STL. The solutions that are fluid when working with a Compact Logix CPU are hard for me to imagine in Step 7... like sequencing with arrays. UGH! It's going to take some time and effort to get fluent. I'm putting together a practice network in my shop, with some spare components. I have some holes to fill in that system, so I'll be back with questions.