siemens cp340 testing

hello.............,

in my configuration i have a cpu 315 -2dp, an input module and a cp340 rs422/485. because that cp340 module is a bit unknown to me i decided to investigate it a bit.

On the internet i've red the story that it is possible to test it on it's own in rs422 without having a communication partner.  i've connected the 'send' site to the 'recieve site' with two wires. So i took a wire and one end i've put in port 2 and the other end i've put in port 4.   And with the other wire i've connected 9 with 11. (see attachement)

after that i programmed the fb's (see left side attachement) with the corresponding db's and stuff that comes with it. so in db1 (red arrow and circle) i've just filled in some values. and than when i0.0 becomes high that values should be transfered to fb10 (yellow arrow and circle). 

but somehow this doesn't work. in db10 the values won't become the same as in db1

but when i0.0 becomes high the lights on the cp340 module flashes up TXD as RXD, so there is happening something. and i asume that when light TXD lights up data is being send out. 

anyone an idea why i don't get the data in db10

gr gerard

Hello

The easiest way to test a CP340/341 is to connect it to a  Serial/USB to RS422/485 convertor.

Connect the Serial/USB end to a PC and run a serial port capturing software like Docklight.

You can easily read the Data transmitted from CP340 in PC and also send telegrams from PC and read in PLC.

Hope this helps

Hello Ayman and Navnag,

Thank you for replying,  I've just red it on the internet and it sounded logic.

But i was experimenting some more and i noticed that if you look at the FB3 ( previous attachment) and i0.0 is high than i assume that the data is being sent. but the outputs of the FB3 (DONE, ERROR and STATUS) all remain the same,  so i don't get an indication if the software that i wrote is good/not good.

even if i try with plcsim and i make i0.0 high on fb3 than 'done, error and status' remain unchanged. what does that mains it must make an indication or so

i was googling that 'serial/usb to rs422/485 converter. can it be that older computers are standerd equiped with that. i saw it before 

gr gerard

gerard32

even if i try with plcsim and i make i0.0 high on fb3 than 'done, error and status' remain unchanged. what does that mains it must make an indication or so

i was googling that 'serial/usb to rs422/485 converter. can it be that older computers are standerd equiped with that. i saw it before

1. you will not be able to test CP340 communication with PLCSIM. You need a physical CPU + CP to do this testing.

2. Older PCs used to have a RS232 serial port. You still needed a RS232 to  RS485/RS422 convertor.
 

3, You can locate several USB to RS485/RS422 convertors in sites like ebay and aliexpress.

Hope this helps

Cheers
Navnag

Hello Gerard,

for first pls look at CP configuration (PLC HW). There you can select your needed 485 or 422 connection. Problem can be with same time Read/Write enabling instructions. Pls look for important thing, that needed statuses like DONE, NDR are changed only for one CPU cycle, so you need must make your needed program addition checks for that situation to right drive your data. On Google are posted lot of samples for 485/422 loop checks. I think it can be prepared with one CP card on CPU, but also example of Navnag with PC USB converter and external application is possible, maybe better.

Update: I will be make better use of Merker M for seting up that inpuls for TX, after that DONE status received, you can simply set it to 0 automaticaly, or use some TX own defined timeout to reset that needed bit Merker. In case of 485 it is needed different TX/RX instruction drive bits on same time, not both TX/RX on same time, isn't full duplex!

Hello,

now I see that you send from FB3 DB1 from DBB_NO -> 2, LEN - 10 BYTES, is it ok?  So your frame to send is:

FFAABBCCDD33FF000000

Offset 2, LEN - 10 Bytes. This frame will be send.

hello.........,

i'am still experimenting and it almost works,  but everytime i download something i get the massage see attachement.  what is that and how do i solve it 

gr gerard

Hello Gérard;

Debugging functions include forcing variables, checking a VAT table, monitoring a block online...

Simply exit any of those functions before you start downloading.

For more hints, look art this previous discussion:

Download to PLC-warning message

https://support.industry.siemens.com/tf/ww/en/posts/84747/

Hope this helps,

Daniel Chartier

Daniel,

That was helpfull, it came because i was monitoring a lot,

But i'am still messing around with my cp340 and i almost managed to send data from my cp340 back to the same cp340. it goes with a lot of experimenting and so.  but now i encounterd something new issue.

see attachement. if i move '2' to db11.dbb50 and than i'am going to monitor db11.dbb50 that '2' becomes 515.  i can not explain this. If i change that 2 to a '1'   that '1' becomes 1  259

how is this possible and what do i need to do to make a 1 moved to a 1 in my db 

gr gerard