RS-485 Serial Interface

RS-485 is a multi-drop serial communication interface. At the application level, it can transmit and receive data in a manner similar to a RS-232 interface with the added benefit that the communication lines can be daisy chained between multiple nodes instead of requiring point-to-point wiring. Within GPL application programs, this port is referenced as "/dev/com4."

For reliable communications, RS-485 lines must be terminated at both ends of the daisy chain and must not have any termination at interior nodes. The controller's RS-485 interface includes hardwired termination. Therefore, the controller must always be at one end of the RS-485 daisy chain.

The RS-485 interface is not available for interfacing to 3^rd party devices when the controller is embedded in a PreciseFlex robot such as the PrecisePlace and PreciseFlex^TM. In these robots, this interface is dedicated to communicating with the built-in Serial I/O boards. See Figure 7-25 and Table 7-16.

Figure 7-25: Connector

Table 7-16: Pinout
Pin	Description
1	24VDC Starting in early 2013, all Guidance Controllers can output a maximum of 2A at 24VDC on the RS-485 connector assuming that the controller's 24VDC power supply has sufficient power. Prior to early 2013, this was limited to only 1.35A.
2
3	GND
4	GND
5	GND
6	VCC
7	GND
8	RS485+
9	RS485-
10	GND
User Plug Part No	AMP 746285-1 or Molex 22-55-2101 or 90142-0010. For the Molex plug, use Molex pins 16-02-0103 and Molex crimp tool 63811-1000.