AC800M Modbus RTU error code :Undefined Function Code 0

We had modbus link to automation, AC800M is slave (ch 3) and link stops occasionally for this kind of messages. AC800M controller log.


Undefined Function Code 0 in GetPendingByteSize()

Incoming Modbus Request Frame is Corrupted

It had worked previously with AC110.

What could be reason ....

Thank for answers.




Add New Comment


JaHa_ABB   

asked 10 days ago



Answers

0

Try with PollTime = 0 for COM3 settings of AC800M

kstoilov   

answered 10 days ago


 


Add New Comment


0

Hi,

Sometimes I had problems with a Modbus serial communication due the parameter "Delay of the RTS-signal" was different of zero.

This parameter is in the editor panel of "<Port number> Com" nodes of the hardware structure of the controllers.

I hope this could help you

Best regards

Daniel Gil   

answered 9 days ago


 


Add New Comment


0

Hi. Thank for hints.

Settings were :

RTS delay = 0.

Poll time =4000.

and did you mead that we should try to increase RTS delay ?

br.

JaHa_ABB   

answered 9 days ago


 


By Daniel Gil on 10/10/2017 | Like (0) | Report

Hi!

Keep the RTS value to zero if serial communication is RS-232.

Only in case the communication is RS-485 or RS-232C (multidrop) you have to set the parameter with a value greater than 0


Add New Comment


0

Check that you use correct speed, no of stop bits, parity. If you use multidrop and 2-wire you need HW handshake or a modem that automatically detects activity on the line.

Delaying RTS gives time for the modem to change direction.

Rolf N   

answered 2 days ago


 


Add New Comment


0

If you use 4-wire then both receiver and transmitter in the Modem can be active on the master side so HW handshake isn't essential on the master. Since the AC800M is slave you need HW handshake or the modem type that detects the stream.

Rolf N   

answered 2 days ago


 


Add New Comment



Get weekly AKS updates


Partner Exclusive Webinars

 

> – Login to the partner portal to register



Points Redemption Program - Redeem your points for ABB training, Bluetooth speakers and mugs. Terms and conditions >


Earn points when you refer a friend
AKS Referral Program is "Live" - Learn more



AKS Experts


avatar
Ask Dieter Henkel   

Rank: 23


avatar
Ask Harsha.D   

Rank: 6

Tech.Support,software and commisioning engineer with Proficient knowledge in 800xA and its products, RNRP,Networking in general.


avatar
Ask Govindaraj   

Rank: 10

Working in ABB India Operation Center. Have Project engineering and commissioning experience in ABB 800xA, Freelance, AC500.


avatar
Ask Flavio Mussolin   

Rank: 4

ABB AVP, Senior Electronic and Automation Engineer with over 30 years of experience in the field of process automation automotive, pharmaceutical, hollow glass, steel and rolling.


avatar
Ask kstoilov   

Rank: 16

Control System Engineer: 800xA, Compact 800, AC500, AC31-50, Advant Master, Simatic, AC&DC Drives 11 years worked for ABB - Control Systems


avatar
Ask Sumit Gargav   

Rank: 2

I have worked with Freelance in majority, with 800xA FD and Melody system partly. Also had opportunity to work with Protocols - HART,Profibus,FF & Modbus.


avatar
Ask nikismith   

Rank: 261

I have been a part of the Recording & Control Factory team for 17 years in total, having spent a number of years as a repairs technician withi the manufacturing department, but being in my current role for 9 years now.


avatar
Ask MMM   

Rank: 5

ABB PA CT Technical Support


avatar
Ask Stefan Stromqvist   

Rank: 1

I joined ABB in the year of 1994 and has since 1999 been working as a Service & Support Engineer at BU Control Technologies in Västerås, Sweden. My areas of expertise are: 800xA Base, 800xA for Advant Master, Information Management, operating systems, RNRP and Ethernet comms/networking in general.


avatar
Ask Rob Lyon   

Rank: 3

info@lymac.co.nz I'm an independent DCS software and commissioning engineer with extensive experience in 800xA and other ABB products. I've worked in almost every corner of the world and still haven't seen it all.