GIO Module - System Overview¶
This page describes some of the key parameters, services and topics you’ll need to interact with when using the RoNeX GIO module. The information here builds on that related to the general RoNeX system which can be found here.
The serial number of the sample RoNeX GIO module used here was 12. On other systems the number 12 will be replaced with the serial number corresponding to the connected GIO module.
Topics¶
ROS Topics provide a fast, flexible way to transfer data between nodes.
Topics can be published or subscribed to from the command line or within a program. For more information see the tutorials.
/ronex/general_io/12/command/digital/0(0-11) [std_msgs/Bool]
By publishing a Boolean value to one of these topics, you can turn the corresponding digital output on or off (if it has been configured as an ouput using the input_mode parameter).
/ronex/general_io/12/command/pwm/0(0-5) [sr_ronex_msgs/PWM]
Publishing to one of these topics configures the corresponding PWM module. There are 6 modules in total, each controlling 2 channels. You can configure the period for each module, and the on time for each channel individually.
/ronex/general_io/12/parameter_updates
RoNeX publishes information on the current configuration of the module i/o channels to this topic, including input_mode, clock divider and PWM period. As the name suggests, parameter updates will be reflected in the data published on this topic.
/ronex/general_io/12/parameter_descriptions
RoNeX publishes a short description of the function of each of the module parameters to this topic.
/ronex/general_io/12/state
This topic contains the current state of all of the channels on the RoNeX module, including digital channel values and input_mode configuration, PWM clock divider and analogue input values. If you’re looking to monitor the activities of your RoNeX module, this is the place to get the information.
Parameters¶
The parameter server acts as a database of information to be shared between various nodes running within your ROS system.
Any of these parameters can be read using the rosparam get command. Module parameters such as input modes or click dividers are dynamic parameters, and as such you need to use the dynamic reconfigure interfaces listed in the changing the configuration section of the tutorials in order for them to update correctly.
/ronex/general_io/12/input_mode_0(0-11)
These parameters (one for each digital io channel) contain the current mode of each digital channel, True for input mode, and False for output mode.
/ronex/general_io/12/pwm_clock_divider
The master clock divider, used in configuring PWM output parameters. For more information on using PWM functionality see the tutorials.
/ronex/general_io/12/pwm_period_0(0-5)
The cycle period for each PWM unit. For more information on using PWM functionality see the tutorials.
Services¶
ROS Services provide a reliable communication method for operations that require a response or confirmation, such as the updating of system configuration.
Any of these services can be called directly from the command line using rosservice call, or from a program as described here.
/ronex/general_io/12/set_parameters
This service allows for dynamic reconfiguration of the module parameters listed above. Usage can be found in the tutorials.