Hallo,

benötige Hilfe um eine Modbus verbindung aufzubauen.

bin relativ neu in TiaPortal und benötige Hilfe beim einlesen von Registern.

Technische Daten:
TiaPortal 15.1 / Baustein MODBUSPN
S7 315PN/DP CPU <--- ModbusTCP <--- Sun2000.

Habe den Baustein wie im Bild eingefügt , wahrscheinlich nicht richtig.

Sun2000 - MODBUS Aktiv+getestet!
ID: 1
IP.: 192.168.3.104
Port: 502
Möchte am besten 2 Register einlesen:
Register Address. (PDF)
32080 / int32 / Power
37113 / int32 / PowerMeter

Translation:

Hello,

need help to establish a modbus connection.

I'm relatively new to TiaPortal and need help reading registers.

Technical specifications:

TiaPortal 15.1 / module MODBUSPN

S7 315PN/DP CPU <--- ModbusTCP <--- Sun2000.

I inserted the block as in the picture, probably not right.

Sun2000 - MODBUS active+tested!

ID: 1

IP.: 192.168.3.104

Port: 502

I would like to read in 2 registers:

RegisterAddress. (PDF)

32080 / int32 / Power

37113/int32/PowerMeter

Hello,

for first pls, this is English speaking Forum so be kind write in English language here. To your problem.

1. your error code show clear info about wrong parameters as Start/End or LEN parameters set values so try look for this and correct parameters. To me, your problem is logical probably, you've set start and end address with same address value inside definition what means 1 register available probbaly, but you ask for 2 registers in block - problem. As next problem is that inside your Online status table you have there start and end address parameters set values 0 what is wrong,probbaly the primary problem.Check attachment.

.2. I don't see any value for your UNIT device ID, is 0 so question is if this is ok, generally 255 or 16#FF is used in case of not serial side devices existed.

I recommend check carefully your TIA version manual with MODBUSPN block part where you have all descriptions about things you need set correctly to have functionality ok. You can do tests with some PC MB TCP Client application connected to your device and test to collect data, this is better for start and after success it can be then better do things on PLC because you can be sure that conection to device is functional.

I've changed a few things, there's no error.

but where are the values written in?

Picture attached

-----------

Habe einiges umgestellt, es kommt kein fehler.
Aber wo werden die werte geschrieben?
Bild im Anhang

Hello,

but where are the values written in?

inside your connection DB structure is also Modbus settings area where are also data areas (1,2,...) where you can specify to what data type you want store data. You need have prepared simple DB as Array or other suitable structure and inside this specific data area you set value of this DB and other parameters like DB elements offsets. It is quite hard to understand for first but is very good for many possibilities with configuration. Pay attention to number of elements to have not error A003 what can point to not have enough space due data type definition and expected length (number of registers to read).

Hello,

I once took a different address, with i16.

is 1 2 3 4 correct in the picture?I'm a beginner, sorry for stupid questions.:-)

Could you help me via Teamviewer?

Hello,

no, generally on Modbus block you're use standard system of addressing as is typical register address (on your left side of picture) so set there expected address of register, correct FC (data type) and length as required. On that connection DB with data areas you need set start and end  Try do tests and check error code/status. Better explained on next post's attachment as Help in TIA provides.

Very sry, not providing help via any system.

Look, you can easy use some PC SW as MB TCP Server to tests your PLC code as Client. Again, you're sure that your external device is ID 1 addressed? As I recommended before, address 255 or 16#FF is expected to use in case of only TCP device is attached/accessed and no serial devices where correct MB Unit ID is required. Very sry, in case you're not experienced then start to improve Modbus knowledge because you can step to problem and you'll be lost. I expect also elementary PLC data types knowledge as mandatory also (DB, offsets, Array elements,...) because then is impossible to help quickly.

Hello,

look at my attachment, there is clear description about that register addresses set in that areas as is on attachment and also inside your TIA help about block.

Hello,

and one important thing to understand functionality. If I good remember, there is info that isn't expected change parameters inside connection DB during runtime. It is clear that in case of more connection as example, you need have prepared more these connection DBs with different settings as you expect. This also means about change inside areas with Modbus parameters. In case you change something, I expect no effect fully but only after restart of PLC (switch STOP/RUN). So in case you do tests with that your problmeatic offsets and addreses and you set some values inside connection DB, you need after that restsrt PLC to take effect. Pay attention to this because it can be very big problem to understand situation when your system isn't functional and you only guess where the problem is. You can easy test this.

Ok, I've prepared little test with my 315-2 PN/DP and this shows typical situation where I request for 10 Holding registers from PC app simulated MB TCP Server. Look at settings on boxes and think about that settings especially inside data area 1, data type 3, DB for store of data -> 3, start from first address to 9-th but request 16#0A (10 registers). If I set REQ to true (violette) then no data will come but error on field 16#A006 will be there - S7 is client: An invalid value was specified at the LENGTH parameter. Easy to check an test. If I change now that data area field end to higher than 10 also, restart PLC with changes (as I mentioned before to take effect) and set REQ true, I'll receive 10 Holding registers from Server without problem.

Hello community,

for the sake of completeness I would like to publish the answer from Wüstenräuber on the same topic from the German forum:

Wüstenräuber

Hello,

Only 1 register is configured in the data areas, namely 37113. However, an attempt is made to read registers 37113 and 37114 on the Modbus block (START_ADDRESS = 37113, LENGTH = 2).

Either set LENGTH = 1 or increase the end address in the data areas.

With Modbus, 1 register always has 2 bytes. If you want to read a value with 4 bytes (e.g. Real or DINT), you simply have to parameterize and read 2 registers.

 Regards,
Jen_Moderator

Hello Jen,

yes, this is correct and also what I mentioned. LEN parameter must be set correctly. I see his problem inside his VAT (Watch) table where his values are set as initial state/startup but then are set via some other steps to 0, they are vissible correctly in that table as orange (actual) values and are 0, this is what I see as wrong and mentioned. Hope I see that correctly.