I am using a node based system to connect to the LOGO and pull data. Before i send hours looking at and rewriting my functions are the following functions even possible with the LOGO using S7(snap7) comms?

- PLC status

- CPU info

- PLC date/time - get/set

- Get Block info/data

 a few more but not as important as these.

I already have Input/Output/Markers but also no counters or timers. I have read some about Modbus working so would it be easier/better to use Modbus instead?

Helmut_13

Hi,

basically S7 or Modbus operates similar fokused on function block parameter. It depends where you have experineces with.

To get data from LOGO! function blocks like a counter:

In you LOGO! Program use use:
<Tools; Parameter VM mapping>.

In the table select the FB (counter you need) and configure a VM-Adress you have not used. Valid VM range is VB0 to VB850. See attached picture.

Then use your SW and try to read the VM-Adress inside LOGO! where you have configured in the VM-mapping table.

If you need to cinfigure a DB number, then use DB1. LOGO! only has a DB1.

Hope this help.

 thank you for the response. i have some experience with both but unfortunately i do not have access using the LOGO software. it is a production level device from another company. i am simply trying to read settings like time, counters, inputs, etc. i am able to get inputs, outputs, and markers but unable to get anything else to work. are LOGO's fully S7 compatable or as i have read partial S7. can i set time/date pull PLC status(Run/Stop) with S7 and Modbus???

Helmut_13

Hi,

if the VM-mapping of function block parameters is not configured and you don't have access to the LOGO! program, then you cannot read/write this parameters.

There is also no possibility to do a RUN/STOPP, Reset via Modbus or S7.

Basically LOGO! is seperated and has a complete different structure then S7 or Modbus. It only offers a way to "exchange" data via VM-mapping and in addition some "pre-configured" information. 

This "pre-configured" information you can find if you open the help in LOGO! Soft Comfort and search for "VM".

Open the first listed entry. Here you can find at what V-adresses you can read/write this pre-configured data.

Pre-configured data:

I, AI, Q, AQ, M, AM, Ni, NQ, NAI, NQ, NAQ and date&time.

Hope this helps

 Thank you for confirming. that is what i was expecting. i have DB1 mapped out and reading but none of the secondary functions(Run/Stop/Status,etc) work with S7, now i know why.

I am able to do functions to the LOGO(read/write time, place in Run/Stop,etc) from the LOGO Soft software. is there a way i can use the same comm setup as the LOGO software? a wireshark capture showed the packets but i have not broken it down yet. Is this possible? Is the a protocol base out there for this comm?

ixo65

Maybe this links help:

LOGO! 0BA7/0BA8

Snap7 discussion

 Yeah i have been pouring over those and other posts for weeks. i just made a step forward though. i took the WireShark dissection to the trial and error phase. turns out if you take the program packet sender(packetsender.com) and send the data packet K\c0\01\e0\00\00\00\00\00\00\00\00SwitchMode\00\00\10'\00\00 in ASCII or 4b c0 01 e0 00 00 00 00 00 00 00 00 53 77 69 74 63 68 4d 6f 64 65 00 00 10 27 00 00 in HEX over TCP connection on port 10005(for me, not sure if its for every connection or PLC) it will do just that - switch from run to stop or vice-versa. i have 4 commands so far that have worked this way. what the return means i am not sure yet but thats for another day. thank you for your help.