COM port usage - Facility Explorer - Part No. 24-10143-918 - Field Device

RS-485 Option Module Installation Instructions

Facility Explorer
Document type
Installation Guide
Document number
Part No. 24-10143-918
Document revision
Revision date

The dual RS-485 option module adds two COM ports on the installed FX80 controller. The controller has two onboard RS-485 ports. In the station running on the controller, these two ports always operate as COM1 and COM2.

Installed serial option modules (RS-232 or RS-485) continue COM port numbering based on proximity to the controller, where the option module closest to the controller base operates as the next available serial COM ports.

For example, if attached directly to the controller, this dual RS-485 option module operates as COM3 and COM4. If another RS-485 option module is attached to it, the second module operates as COM5 and COM6.

Note: FX80 controllers support a maximum total of four option modules across all option types. If two dual RS-485 modules are used, you can only add one additional non RS-485 module for a maximum total of three modules.
Figure 1. COM port numbering examples