Hi. I have a s7315 ​​2DP cpu, and a 341-1ah02 card. I have to use maestro.class communication by request of the equipment to which I am going to connect that it is an AZL5 (that is the program unit of a wise drive 200, eauipo to control a burner). Download several examples in the ones that give me information, but I'm starting to use these computers and I do not have much skill. In the example download that is the "zxx21_04_ptp_com_modma" in function FC21 and FC23 makes calls to database DB40 which has no data available. I think that's where I should get the data sent by the slave. I appreciate your support on how they work and where I can observe data coming from the slave  regards

Hello nomolina;

Ifound the following document on the AZL5 Modbus communications that can show you where to find the Modbus registers you want to read and write from your burner system:

AZL... Modbus User Documentation - Siemens

Starting on page 9 you will find all available reg9sters your Modbus master can call from the slave, starting at offset 0, "Phase"; use Modbus function 3 to call base address 40001, offset 0 and you will get "Phase".

The following manual was written for the same S7-300m famiy with a CP 3141, but programmed in Step 7 v5.5 insteadmof TIA Portal; it contains a description of the FCs and DBs used in the sample program you are studying, even though this was developped on TIA Portal you might find the information useful.

SIMATIC S7-300/S7-400 Loadable Driver for Point-to-Point CPs: MODBUS protocol, RTU format, S7 is master

Hope this helps,

Daniel Chartier

Many thanks dear Daniel 
I downloaded the project and converted it to Aunt Portal, 
but I came out with a series of errors regarding some undeclared variables. 
will be called in the CF but the variable is found in the DB.  
for example.
 in the initiation FC says     
       L  B # 16 # 00
       T "Work DB Send" .a [1] SEND- Work-DB      
       T "Work DB Receive" .a [1] // RCV- Work-DB 
 // --------------------------- 
// Reset counters / STATUS 
// ---------------------------       
      L W # 16 # 0       
      T %DB40.DBW6 // SEND- Work -DB       
      T %DB40.DBW8       
      T %DB40.DBW12       
      T %DB40.DBW14       
      T %DB41.DBW6 // RCV- Work -DB       
      T %DB41.DBW8       
      T %DB41.DBW12       
      T %DB41.DBW14  

but in DB 40 and 41 these directions are not found. 
Only an array of 20 bits.  

I appreciate your help in advance  

regards

Thanks for your quick response. 
I still have doubts as I make the call to address 40001.
 In which part of the program can I make the call. 
 Thank you

Yes, but they recommend me in a previous message: 

"Starting on page 9 you will find all available Modbus master from the slave,
 starting at offset 0," Phase ", use Modbus function 3 to call base address 
40001, offset 0 and you will get" Phase ". 

 That's why I ask how I make the call.  

Thank you, I will read your recommendation

Hello nomolina;

Frst, there are already TIA Portal versions of the Modbus master programs (for CP 4341):

Sample program MODBUS Master (standard block) zXX21_04_PtP_Com_MODMA.zip for STEP 7 (TIA Portal)

Second, there is a very important manual that you must become familiar with if you want to program the CP 341 as a Modbus master:

https://support.industry.siemens.com/cs/document/1220184/simatic-s7-300-s7-400-loadable-driver-for-point-to-point-cps%3A-modbus-protocol-rtu-format-s7-is-master?dti=0&lc=en-FR

To setup a Modbus read job in the CPu program, one of the steps is to prepare a Source send DB (in the sample progrm, this is DB42); this DB is where the programmer prepares the information for the Modbus Master read job: the slave address, the Modbus Function (Function 03 calls registers at Modbus address 4000x), the number of registers and he start offset. Look at the attachment below, and study smiffy's excellent presentation on Modbus basics ("Modbus General description", in the Conference Communications).

If you ant to read more than one register with the same start address, change the value in DB42. If you want to read starting at 40010, chang the start address value in DB 42. If you want to read from another slave, craete another Source SendDB with a new slave address, start address and number of registers and call it in a new Modbus master job..

Hope this helps,

Daniel Chartier

Thank you so much. 
 With regard to DB 40, should I modify it too? 
why in this database is the one that tells me that I have nothing declared.?

dchartier

Hello nomolina;

Frst, there are already TIA Portal versions of the Modbus master programs (for CP 4341):

Sample program MODBUS Master (standard block) zXX21_04_PtP_Com_MODMA.zip for STEP 7 (TIA Portal)

Second, there is a very important manual that you must become familiar with if you want to program the CP 341 as a Modbus master:

https://support.industry.siemens.com/cs/document/1220184/simatic-s7-300-s7-400-loadable-driver-for-point-to-point-cps%3A-modbus-protocol-rtu-format-s7-is-master?dti=0&lc=en-FR

To setup a Modbus read job in the CPu program, one of the steps is to prepare a Source send DB (in the sample progrm, this is DB42); this DB is where the programmer prepares the information for the Modbus Master read job: the slave address, the Modbus Function (Function 03 calls registers at Modbus address 4000x), the number of registers and he start offset. Look at the attachment below, and study smiffy's excellent presentation on Modbus basics ("Modbus General description", in the Conference Communications).

If you ant to read more than one register with the same start address, change the value in DB42. If you want to read starting at 40010, chang the start address value in DB 42. If you want to read from another slave, craete another Source SendDB with a new slave address, start address and number of registers and call it in a new Modbus master job..

Hope this helps,

Daniel Chartier

Good evening dear Daniel. 
I have been working and using the manual and the program to adapt it to my
 needs, but I have only managed to increase the error count.
 I add screenshots to display with the purpose of finding the error. 
I appreciate your help and I have little to do. 

 regards

Dear Daniel, 

by checking the configuration onlinene the cp341, I saw this, 
one must buy a separate license or when buying the cp341 comes inside the 
installation CD.  

regards

nomolina

 

Thank you so much. 
 With regard to DB 40, should I modify it too? 
why in this database is the one that tells me that I have nothing declared.?

dchartier

Hello nomolina;

Frst, there are already TIA Portal versions of the Modbus master programs (for CP 4341):

Sample program MODBUS Master (standard block) zXX21_04_PtP_Com_MODMA.zip for STEP 7 (TIA Portal)

Second, there is a very important manual that you must become familiar with if you want to program the CP 341 as a Modbus master:

https://support.industry.siemens.com/cs/document/1220184/simatic-s7-300-s7-400-loadable-driver-for-point-to-point-cps%3A-modbus-protocol-rtu-format-s7-is-master?dti=0&lc=en-FR

To setup a Modbus read job in the CPu program, one of the steps is to prepare a Source send DB (in the sample progrm, this is DB42); this DB is where the programmer prepares the information for the Modbus Master read job: the slave address, the Modbus Function (Function 03 calls registers at Modbus address 4000x), the number of registers and he start offset. Look at the attachment below, and study smiffy's excellent presentation on Modbus basics ("Modbus General description", in the Conference Communications).

If you ant to read more than one register with the same start address, change the value in DB42. If you want to read starting at 40010, chang the start address value in DB 42. If you want to read from another slave, craete another Source SendDB with a new slave address, start address and number of registers and call it in a new Modbus master job..

Hope this helps,

Daniel Chartier