Remote I/O is the portion of the controller’s I/O that is typically installed away from the PLC housing and that requires an interface module to communicate with the I/O processor at the CPU. Communication to the primary housing at each drop is accomplished through coaxial cable. A remote I/O system may consist of single or multiple housing at each drop.
The S908 Remote I/O Processor Option Module provides remote I/O capability to the 984-685/785 controller lines. Using the S908 remote I/O processor, these controllers can address up to 31 remote drops of 800-series I/O. In addition, each drop can support two ASCII communication ports (maximum of 32 ports available). S908 processors are available with either one or two coaxial cable connectors for single or dual cable configurations.
The S908 Remote I/O Processor occupies one option slot in a 984-685/785 controller. A 785upgrade kit is available to support a 16 drop Quantum I/O S908 network. The AM-E785-QK0 kit includes:
• 785 downloadable executive, #SW-E785-Q00.
• S908 16 drop cartridge, #AS-Q908-016.
This 785 upgrade kit supports up to 16 drops of 800 series I/O and Quantum I/O. Each drop must be either 800- series I/O or Quantum I/O. A combination of 800-Series I/O and Quantum I/O is not supported within a drop. The local drop supports only 800-series I/O.