Downloading a program to S7-400H


Thread Starter


I am having a s7-400h Station. how can i download the configured program to the PLC. it is necessary to load the Program to Both Master and slave?

if i am changing the hardware setting, how i can load it?
Same if i am changing any FB/FC then?
You have to connect to the CPU/PLC via the appropriate port (such as a MPI port), then you could download it into PLC.

You should have simatic S7 software.

I Got one PLC program backup in Simatic Manager. In this, if i am searching for Analog/Digital I/Os in Reference, i cannot find it. I Guess It is programmed through CFC/Graph and i don't have any experience on this. i only know STL/Ladder. There are all the blocks written in STL. But i cannot find any I/Os in that.

Please tell me whether i can get any documents to Checking the program.
Dear Ranjith,

the right answer to this question depends on many things. Generally, there are many ways in the world of SIEMENS SIMATIC PLCs to compile and load. Whether you use the DCS-System PCS7, or only a single 400-PLC-Station, you always need at least a version of the STEP7-Manager to program, compile and in the end load hardware. SIEMENS generally gives you all possibilities of part and full compiling and part and full loading your step7 program. Part compiling and part loading means, that you only compile the changes made to the program since last download to the PLC. You can even load your changes to PLC afterwords without stopping the CPU (Online-Load capability) and this not only with redundant SIMATIC Stations, but also with single PLCs. Of course Online-Loading does not work in all cases, for example if you change data-blocks, interface (in-/output signals) of function blocks or some fundamental hardware-configurations (but some little changes to HW-config can also be loaded online e.g. adding an input or output module, adding a profibus slave etc.). Generally you always have the choice of what you want to load. You can load only hardware (or hardware changes) with the hardware-configurator, you can load only connections with Net-Pro or only changes to connections. You can only load data-blocks or changes made to data-blocks. you can load only the program (written in SFC, CFC, AWL, KOP, FUP, SCL) or only changes to the program. Of course you can compile everything as well with one mouse-click and load everything at once. In the last case of course you have to go over a stop of the CPU. But be aware of the fact that if you once full compile the programm, you will need to full load the CPU too (with CPU-stop). So always check first, that you only compile the changes (if possible!) in order not to lose the online-load-capability.

The programming interface can also be very different. You can directly connect to the mpi-interface of the PLC with a serial-to-mpi or usb-to-mpi adapter. If you have a communications-processor connected next to the CPU you can connect via ethernet(industrial ethernet), which of course is the most convenient way of loading, because of high transfer data rate.

In the case of a redundant SIMATIC STATION "H"-System with a master and a slave cpu the loading process is managed by the Step7-Manager and the firmware of the PLCs in the background. Changes made only to the program can be compiled and loaded to the redundant system, as if it was a single system. In fact the program is downloaded to one of the two CPUS and the other CPU wil be updated online and automatically. This is done by the firmware running on both CPUs, which are communicating over the optical-redundancy-link-bus between them. After downloading the new program, the master will still be the master CPU, and the slave remains the slave. As it is also possible to load changes to the hardware-configuration of a redundant System ONLINE(!), you have to know that after downloading the new HW-configuration the master-CPU will become the slave, and the slave will become master, because the new hardware-config will first be loaded to the hot-standy-cpu (slave). After that, the system will switch over to the Slave to become the new master and the master will become the hot-standby CPU (the new slave), which in the last step now will be updated online to new HW-config.

As you see, I can write books about compiling and loading SIEMENS PLCs as there is nearly nothing you can not do with SIEMENS systems. I hope I gave you first insight and overview. If you have any other questions, please be a bit more specific of what you exactly are trying to do.

Best Regards,

Dear Marco Thank you for the reply

I can download the Hardware setting/Netpro to my CPU but regarding the program,I cannot to do that.When I am trying for that,with normal blocks(FC/FB/DB/OB)it is showing load memory error,or compress memory.....

I tried to download it through CFC,the same is happening,it is showing "Hardware error,patch not found" in fact I don't have much experience in this CFC/SFC. I Got the PLC program backup from somewhere. Also In this, if I am searching for Analog/Digital I/Os in Reference, I cannot find it. I Guess It is programmed through CFC/Graph and I don't have any experience on this. I only know STL/Ladder. There are all the blocks written in STL. But I cannot find any I/Os in that.

Can you tell me any solution. Please tell me whether i can get any Help documents or manual to Checking the program.
Ok then,
step by step.

Does the hardware setting match the type *AND* Firmware-Version of the PLCs you are trying to download your programm to? You have to check the numbers starting with "6ES7..." written on the PLC and the configuration in the hardware-configurator. Do they match?Do you see any warnings while loading the hardware?

Tell me how did you install your SIEMENS software on your computer. Actually setting up a working S7/PCS7 Engineering system is quiet a hard thing to do and normally takes hours. Did you install all components of the software package in the right sequence? Did you install all hot-fixes and security patches? Are we talking about a complete PCS7-Software-package or just an STEP7-Application at all?There are big differences between them and you will not be able to open and load a PCS7-project with only having the STEP7-Manager installed.

You wrote about master and slave CPUs, which means you are trying to set up a redundant 400H-System with two CPUs. This generally is not an easy way of getting started with SIEMENS Systems!! Why don't you try to start with a single CPU and a little single STEP7-programm?

Hi Marco,

Thank you for your support..

Now i can download the hardware settings and Netpro to my PLC.

But the problem is if i am trying to download the CFC blocks to my PLC,it is giving the error message "Available load memory insufficient for the Program" i had checked my PLC memory it is 256 KB Ram and 4 MB EPROM.

This condition how i can load my Program?

if i need to flash the program to EPROM what is the method to do that?

down load to flash memory card directly as follows

Blocks> download> download to memory card