GE HE500TIU050 Apr CH TIU200/201/202/203 GFK-1819, 1 TIU20X Configuration of the RS-485 Port

PAGE 30	06 Apr 2000	CH. 5: TIU200/201/202/203
GFK-1819

5.5.1TIU20X Configuration of the RS-485 Port

The configuration bank (shown in Figure 2.23) sets the parameters of the RS-485 port as described in Table 5.1.

	Table 5.1 – Configuration Bank
Switch 1	ON: Pull-up (must be used together with switch 3)
	OFF: no Pull-up
Switch 2	ON: 120Ω termination
	OFF: no termination
Switch 3	ON: Pull-down (must be used together with switch 1)
	OFF: no Pull-down
Switch 4	Reserved for future use

NOTE: Switch 1 and 3 must be used together. Either both pull-up and pull-down are used or neither is used.

Pull-upand Pull-downswitches are used to increase the signal level on the RS-485 bus. This is useful if there is a long bus and a significant amount of attenuation is anticipated.

Termination resistance of 120Ω must be placed across each end of the RS-485 bus. With switch 2 ON, a 120Ω resistance is placed across the bus. This should only be used if the TIU050/10X/11X/20X is the last device at either end of the bus.

5.6TIU20X Dimensions

￿￿￿￿￿+0.02µ>￿￿￿PP@

-0.00

￿￿￿￿µ+0.02	>￿￿￿+0.5
		72/(57,8$￿￿1&(6;$5(&87287￿￿￿￿￿￿￿µ>￿￿￿'(7PP@81/(66$,/667$7('27+(5:,6(
-0.00	-0.0	83￿￿￿￿µ&RUQHU>5$',86,6$&&(37$%/(￿PP@

Figure 5.8 – TIU20X Cutout