Today is...
Sunday, October 20, 2019
Welcome to Control.com, the global online
community of automation professionals.
Featured Video...
Featured Video
A tutorial introduction to programming using the QuickBuilder Programming Environment.
Our Advertisers
Help keep our servers running...
Patronize our advertisers!
Visit our Post Archive
Modbus RTS Terminal Server
Problems with RTS terminal server, values from RTU drop to zero.

Hello,

I have RTS terminal server (Modbus switch). Values from RTU drops to zero. Is there modbus versions that could not be communicating properly with our RTS terminal server? Or it's only one Modbus version.

Regards

If there's no reply 2 weeks then others are as confused with the lack of specifics as I am.

1. What brand model terminal server/MODBUS switch are you using? Can you provide a link to the spec/manual? I'm not sure what kind of functionality it is supposed to be providing.

2. For serial/Ethernet gateway/converters, models with specific firmware for MODBUS RTU are used because of MODBUS RTU's timing and message integrity requirements. Is your device MODBUS RTU specific?

3. Has this equipement worked before and has now failed or is this task commissioning new devices?

4. When you say 'values from RTU drop to zero' does that mean that the only values received are zeroes, when the known source value is not zero?