cp341..modbus...ASCI II and problem!!!

unclehamid

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Join Date
Feb 2007
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shiraz
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I want to access some data(9 word) from cpu315(slave) through modbus to a king fisher plc (master)
I use cp341(rs485 ..341-1ch02-0ae0),ASCI II
in HWconfig 256..271 input address-256..271 output address
but problems
1-there is no modbus address for cp341
2-in master(king fisher)which address assign to input 256..271
3-I don't know modbus at all!!!
we have another programer for fisher king plc but he knows nothing about cp341 and siemens he ask me following question
can someone explain me about it.
 
Did you purchase the loadable driver for Modbus ?

The HW addresses 256..271 are used to communicate from the S7 CPU to the CP341. It has nothing to do with the Modbus addresses.

I would assume that togehter with the loadable driver you will have documentation with sample projects to use in you program.
 
thanks JesperMP
we bought cp341 with a slave dongle that is pluged behind the module.we also have cd in the package it contain a driver that I installed it in pc(simatic manager)and some manual
there is sample project but we don't have example related to
ASCI with RS485(there is example with rs232 and 3964)
should we buy sth elese?please help
 
there are 4 protocol in cp341
ASCI,3964,rk512 and printer
we can not select modbus RTU(may be modbus RTU is one of 4)
and our modbus programmer just know that fisher king support ASCI

there is only one example when we install driver
it would be added to simatic manager."zXX21_01_PtP_Com_CP34x"
there is no example of modbus RTU.
 
Last edited:
You cannot make the CP341 talk Modbus via the ASCII driver.
And you write tht you have a dongle for the CP341, which is not needed for ASCII, but needed for Modbus. So what exactly is this dongle (type number) ?

CP341 available drivers: RK512, ASCII, 3964(R), loadable driver.
 
Last edited:
Dear JesperMP
I ask programmer about modbus RTU and king fisher support it
and he also said to me about another cd that comes with dongle but I don't see its cd yet.as I found from your post
, "loadable driver"should install on modbus master PLC(king fisher).is it right?
I don't insist in ASCI if other protocol works we can check other protocol.
 
dear JesperMP
I am waiting for CD I will recive the pakage next week and cd
I am reading the pdf I will continue this thread I hope it help other too.
 
You can download the sample project from the Siemens support web site, as well as the configuration tool that you will need to configure the CP module in the hardware configuration of Step 7.
 
I downloaded the file. during instalation it adds modbus RTU protocol
to your cp341 .after configuration (set modbus address,assign some I/Q/M and data block to their address in modbus) you should load driver into your cp341 and I use sample program it works.
but I still have problem with DB (we can see I/Q/M in modbus master but we couldn't accses to DB)
 

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