Member Login
Search
Jump to a Date
Sponsored Communities
Cool stuff
Neat Stuff

Visit our shop for nerds in control lifestyle products.
Thermal Overload
The threads that wouldn't die...
- PC reliability?
- Windows, real time
- PID loops
- PCs vs. PLCs
- Replacing people
- MS 'monopoly'?
- Software quality
- Where do we go from here?
- Why pay?
- PC reliability?
- Windows, real time
- PID loops
- PCs vs. PLCs
- Replacing people
- MS 'monopoly'?
- Software quality
- Where do we go from here?
- Why pay?
Fortune
Some people have a way about them that seems to say: "If I have only
one life to live, let me live it as a jerk."
one life to live, let me live it as a jerk."
RSS Feed
www.control.com/rss/
To get a personalized feed, become a member at no cost.
As I have explained before, I try to send data to a Modbus slave and the answer from it is error code number 9. I'm using the function 6 and 16 (both are implemented in the device according to the manual) and I obtain the same response all the time. After all I tried to read data from the device (using function 3) and I read some values... Then the communication is ok but only in one direction and I need it in the other. After reading the manual I have checked that the protocol is Modbus JBUS... Can this be the problem??? What is the difference between them??? Should I change the devices and try with another real Modbus protocol?
Thanks.
email: miguel. allende at ingeteam. com
Thanks.
email: miguel. allende at ingeteam. com
Exception code 9 is not a Modbus specified exception code. Yhe protocol specifies codes 0x01 to 0x08 as well as 0x0A and 0x0B. It is possible that the device manufacturer of this hardware has specified their own codes.
What is the Make, Model and manufacturer of the device?
Do you have documentation of their Modbus implementation that has a list of their exception codes?
Fred Loveless
Senior Application Engineer
Kepware Technologies
http://www.kepware.com
What is the Make, Model and manufacturer of the device?
Do you have documentation of their Modbus implementation that has a list of their exception codes?
Fred Loveless
Senior Application Engineer
Kepware Technologies
http://www.kepware.com
To my knowledge JBUS is the same as Modbus, except that in Modbus register addresses start with a '1', like Modbus holding register 400001, JBUS starts a '0'. So you may find you are one register out.
You need to find out what error numbeer 9 means.
As you have not told us what equipment/manufacturer you are using, we cannot help you much. I suggest you contact manufacturers of Modbus master and slave.
You need to find out what error numbeer 9 means.
As you have not told us what equipment/manufacturer you are using, we cannot help you much. I suggest you contact manufacturers of Modbus master and slave.
Hello,
The only difference, that I know, between JBus and MODBUS is the register number.
To read/write a holding register:
40001 = 0 MODBUS
40001 = 1 JBUS
So your addressing may be off by one.
Download the free simulator from htp://www.peakhmi.com and if you have any troubles send an email to support.
Ciao,
Mark
htp://www.peakhmi.com
The only difference, that I know, between JBus and MODBUS is the register number.
To read/write a holding register:
40001 = 0 MODBUS
40001 = 1 JBUS
So your addressing may be off by one.
Download the free simulator from htp://www.peakhmi.com and if you have any troubles send an email to support.
Ciao,
Mark
htp://www.peakhmi.com
From Control Engineering magazine...
Related articles from Control
Engineering magazine- Wireless manager for instrumentation and control devices
- New podcast: One road to wireless instrumentation
- Upgraded communication modules make PLC to PLC communications easier
- Industrial Ethernet advantages using Profinet protocol
- Fieldbus Foundation Seminar: Chicago
- Radios for long-distance use in industrial mesh network
- Embedded: Precise Time Protocol enables new-generation Ethernet mobile networks
- Optimize field wiring with decentralized IP 67 fieldbus system
- Pack Expo: SERCOS real-time communications for packaging
- Modbus RTU master, distributed I/O in compact package: microNCS
Above articles copyright 2008 Reed Business Information.
Subject to its Terms of Use.
Your use of this site is subject to the terms and conditions set forth under Legal Notices and the Privacy Policy. Please read those terms and conditions carefully. Subject to the rights expressly reserved to others under Legal Notices, the content of this site and the compilation thereof is © 1999-2008 Control Technology Corporation. All rights reserved.
Our Advertisers
Help keep our servers running...
Patronize our advertisers!
Patronize our advertisers!




