Correct modbus configuration, openHAB 2

Hello. I need your help again concerning modbus configuration. I have got a modbus server and I want to connect there from openHAB 2.
First I have replaced openHAB 2 by modbus poll (see http://modbustools.com/modbus_poll.html) with connection setup “Modbus TCP/IP”, IP address 127.0.0.1, Port 502, IPv4. and it worked well. What do I need to configure now?
I have got conf/services/modbus.cfg with the content:
tcp.slave1.connection=127.0.0.1
tcp.slave1.type=coil
tcp.slave1.length=2
My items file contains the line "Switch LightSwitch “Light” (roomA) {modbus=“slave1:0”}

Is it possible that my problems are because I haven’t define any things? Do you know what things I need for this?

You haven’t told us what your problem is. What do you see in logs?

If you are using a 1.x version binding (and I would recommend that for Modbus for now), then you do not get involved with Things.

I’m sure you know 127.0.0.1 is localhost, so guessing your MB server is something on the same box as OH

Normally there would be slave ID and register address in a MB config as well, if you are using the defaults make sure they are what you (your MB server) expects

When starting modbus server, there is the log:

org.osgi.framework.BundleException: Could not resolve module: org.openhab.binding.modbus [207]
Unresolved requirement: Import-Package: gnu.io
at org.eclipse.osgi.container.Module.start(Module.java:434)[org.eclipse.osgi-3.10.101.v20150820-1432.jar:]
at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.incStartLevel(ModuleContainer.java:1582)[org.eclipse.osgi-3.10.101.v20150820-1432.jar:]
at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.incStartLevel(ModuleContainer.java:1562)[org.eclipse.osgi-3.10.101.v20150820-1432.jar:]
at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.doContainerStartLevel(ModuleContainer.java:1533)[org.eclipse.osgi-3.10.101.v20150820-1432.jar:]
at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.dispatchEvent(ModuleContainer.java:1476)[org.eclipse.osgi-3.10.101.v20150820-1432.jar:]
at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.dispatchEvent(ModuleContainer.java:1)[org.eclipse.osgi-3.10.101.v20150820-1432.jar:]
at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)[org.eclipse.osgi-3.10.101.v20150820-1432.jar:]
at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:340)[org.eclipse.osgi-3.10.101.v20150820-1432.jar:]

It seems to be a gnu.io but I don’t know what it is or where I need it.
I have got org.openhab.binding.modbus-1.9.0.jar so I don’t need things, ok.
Yes, they are on the same machine.

These look relevant


Have you tried running
feature:install openhab-transport-serial

from console?

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