Siemens Serial Module

blacksilver80 · Mar 9, 2007

im new here and to Siemens well right now im trying to connect an outside device to a S7 CPU 315-2 DP to send ASCII code. I guess i need a serial module in the PLC rack namely a CP 340 or do i need a different one and can i talk to two different devices through just one serial module??????????????

Werner · Mar 9, 2007

I have used CP's in the past. I can't remember which one. I used it to communicate with 11 movimots. What you must find out is:

- Communication speed (baud rate)
- start/stop bits
- Communication protocol (Modbus, or?)
- Can the two devices be setup to use a common communication protocol?

So it all depends on what youre trying to accomplish. Maybe you can give us some more information about the two devices you are trying to communicate with.

blacksilver80 · Mar 9, 2007

I need to receive an ASCII comma delimited string from a tester and the tester has only serial comm. I take it i need a serial module in my rack to facilitate communications between the PLC and the tester,my question is do i use a CP 340 for this kind of communication as the serial module???
and i have two testers so do i need two serial modules????
Im using Profibus network
Im good at debugging programs but like setting the hardware and communication is really difficult for me.
I have to find the Baud rate and other stuff but right im trying to figure out the hardware on this project
thanks

S7Guy · Mar 9, 2007

The CP340 will work fine. You will have to buy the correct "flavor" according to whether you are using RS232 or RS422/485. If you are using RS485, you'll be able to connect to multiple devices.

AlanSmith · Mar 10, 2007

There are a number of companies who sell Serial to Profibus converters. The advantage of these is that they can be mounted next to the ASCII device, preventing any problems with the RS232 cable length. You can fit as many of them as you like (upto the Profibus Limit)

Do a web search for "Serial to Profibus converters" (or something like that)

Regards
Alan

blacksilver80 · Mar 10, 2007

thanks guys !!!!

DeviceMaster-UP · Mar 12, 2007

Our company also makes a product which offers serial to PROFINET. Just google the part number 99011-6, and you should find the details. For whatever reason, I am unable to post a link here.

Regards,

s7xp.com · Mar 12, 2007

Be aware: CP340 only support 9600 baud max. Not very fast for ascii comms. For more speed (and money) use a CP341.

Prince · Mar 13, 2007

I am no completely about this but I remember that Siemens had a DP/RS232 coupler I found it from my old BOM new catalogs does not include this.

DP/RS232 Coupler
6ES7158-0AA01-0XA0

ALU · Jan 13, 2009

S7Guy said:
The CP340 will work fine. You will have to buy the correct "flavor" according to whether you are using RS232 or RS422/485. If you are using RS485, you'll be able to connect to multiple devices.

Hi S7GUY,
Could you confirm me about my system below is possible or not? I am so confusing because I cannot find parametter in Step7 function which use for attatching slave units's address

(in below sketch is display's address)...And, here is just my thinking

(I have S7-300, CP340 and 05 display on my desk, but not connected), do you have any connection diagram?
Thanks in front! Here is my sketch diagram:
(Display,#1)------->>returned ASCII String>>----RS485port(CPU31x-2PtP; CPU31x-2DP+CP340)
(Display,#2)---|
(Display,#3)---|(Rs485)
(Display,#4)---|
(Display,#5)---|

Siemens Serial Module

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s7xp.com

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Prince

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