Hello everybody,

i need some help with my modbus communication. I tryed everything, but it is still not working.

I use the ET 200SP CM PtP communication module (6ES7137-6AA00-0BA0) to read data via modbus out of my device. At my device i set the modbus settings to:

Baudrate: 19200

party: none

Stopbits: 1

ID: 1

Byte Order: ABCD.

The same settings are uesed in my hardwareconfig of the CM PtP and in the settings for the Modbus_Comm_Load and Modbus_Master in my Programm. I try to read the hold-register with the Modbusfuctioncode 03.

But i still get the errot 81E2: "Frame aborted: Character frame error"

I attached the Tia V14 programm of my testsetup.

It would be nice if someone could help me :)

Hello M@tth1 

I saw your program, I believe that you need to write 2 to the LINE_PRE in DB3.

Ichar_gap = 0

mode = 4

line_pre = 2 

all these has to be done with the load communication. you can set them in the DB3 as initial values

also for the data address I use the same address as mentioned in the sensor manual. although the manual says the register address should be the address -1. but I saw this doesnt work for me. I think the MB master do it internally.

if this doesn't work then check the cable for right connection.

regards

T_Ebrahem

NOTE: If STATUS 16#81E2 occurs
although equal settings for start bit,
data bits, parity bit, data transmission
rate and stop bit(s) please check the
connection line of the communication
partners (Table 6-2 No. 3) and the
receive line initial state "LINE_PRE" :=
2 (preferably set only by the Master).

Link

thx for your answers,

i tried it with your settings of:

Ichar_gap = 0

mode = 4

line_pre = 2

but this leads to the error 80C8 "The slave does not respond within the set time"

Shouldn´t be the line_pre set to 0? At least the help of Tia says that.

"Receive line initial state. Valid initial states are:

• 0 = "No" initial state¹⁾

¹⁾ Required setting for the use of PROFIBUS cables with CM 1241 for RS485"

I also check the wirering and it is correct.

M@tth1as

thx for your answers,

i tried it with your settings of:

Ichar_gap = 0

mode = 4

line_pre = 2

but this leads to the error 80C8 "The slave does not respond within the set time"

Shouldn´t be the line_pre set to 0? At least the help of Tia says that.

"Receive line initial state. Valid initial states are:

• 0 = "No" initial state¹⁾

¹⁾ Required setting for the use of PROFIBUS cables with CM 1241 for RS485"

I also check the wirering and it is correct.

 

 Hello

do you use PROFIBUS cable? as this note says that it required setting for profibus.

for the Error 80C8. try termination resistors and use shielded and twisted cable. hopefully this work. otherwise look at my answer for another post where this error killed my hope. 

**********************************************************************************************

((I got the same error code with my 1500 setup, you can see it here. I tried all the solution that suggested by people who got the same error. but nothing worked for me. I made a request to Siemens and they found it very strange, they suggest me to check if the Siemens CP card send a frame to the bus through any terminal software as I have the TX led blinking each time the MB master send a request frame. so I did the following:

I connected my sensor to the PC and here I can read registers through the software that provided by the sensor manufacturer. I run the terminal program and made it listen to the used port. here I can see the messages that exchanged between the sensor and the PC. through this Im sure that my sensor works fine.

then I connected the sensor to Siemens system and I run the terminal to listen to the bus, I used RS485 to USB converter. Although the send FB Done shows true and the TX led blink, I saw nothing in my  terminal. which means that the Siemens not sending anything.

To be more sure I used the oscilloscope. when It connected to the PC (manufacturer software) and there is data exchange, I can see frame of pulses of 5V signal (messages frames) in the oscilloscope. and when it connected to  Siemens card I see only 2V pulses signal. which means that the card is sending request but the voltage is not enough to be recognized by the sensor. then I contacted Siemens again. they said that there is high possibility that the output circuit got defected and can not generate the right voltage, you see the led blinking but the output is not driving enough voltage. then we agreed to send the card back for repair.

so I suggest you to do same as I did and see if you can see any signal coming out the cp card, you can useHerculesterminal. and if something is not clear here you can always write me and Im happy to help))

************************************************************************************************

I hope someone here already found solution for this error.

regards

T_Ebrahem