The Remote Input and Output (RIO) module (Figure 31-1) can add optically isolated digital input and output signals, analog inputs, and serial ports to any Guidance Controller. The RIO module connects to a controller via Ethernet and can be placed anywhere within the controller's local network. The RIO supports the MODBUS/TCP communications protocol and uses a variation of this to interface with a Guidance Controller. MODBUS/TCP is a "open" standard that is widely employed in industrial manufacturing environments to interconnect intelligent devices and intelligent sensors and is compatible with all standard Ethernet TCP/IP networks. An RIO can also be configured as a standalone controller or as a standard MODBUS/TCP slave device. The latter capability permits a PC that is executing MODBUS/TCP master software to directly connect to an RIO.
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The RIO contains unshielded 24VDC signals and pins. This product is intended to be mounted in a cabinet or machine chassis that is not accessible when power is turned on.
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The Remote Input and Output (RIO) module can operate in one of two primary modes. It can act as a remote I/O expansion module for a Guidance Controller or a PC, or it can operate as an independent master controller that runs GPL programs in the same manner as a standard Guidance Controller.
As a remote I/O expansion module, the RIO executes its I/O Scanning Software and sends a MODBUS/TCP message to the master whenever an input changes. It also responds to any requests it receives from a master to access the RIO's various I/O ports. This mode of operation is selected by setting DataID 211 "GPL MODBUS/TCP master" to False.
As an independent master controller, the RIO can execute GPL programs that can control its local IO. These programs can also access other RIO boards or MODBUS/TCP slaves since, in this configuration, the RIO can function as a MODBUS?TCP master. In this mode of operation, the RIO can still be accessed as a MODBUS/TCP slave in the same manner as a Guidance Controller. This configuration is selected by setting DataID 211 "GPL MODBUS/TCP master" to True.
The Standard RIO module provides 32 optically isolated digital inputs and 32 optically isolated digital outputs and one RS-232 serial port. An enhanced version of the RIO adds 4 analog inputs, a second RS-232 port and one RS-422/485 port. Up to 4 RIO modules can be connected to a single controller.
All of the digital input lines can be jumpered as sinking or sourcing in blocks of 8 signals. Different versions of the RIO hardware must be purchased in order to obtain either all sinking or all sourcing digital output signals.
The RIO is an intelligent device and shares many of the software features available with the Guidance Controller. The software configuration is stored in the Configuration and Parameter Database that is accessed with pages viewed by a web browser. For detailed information on the web interface and the Parameter Database, see the Software Setup and Introduction to Software sections of the Controller Software chapter of the PreciseFlex™ PreciseFlex Library.