3 RS232 TO 2x RS232 FALLBACK SWITC
3.1 DESCRIPTION
Fallback switc is communication device t at switc es data between two master ports and one
slave port. It is intended to connect one device (RTU) to two master devices (PC).
T is device contains t ree RS232 interfaces, one slave and two master ports. W en data
comes to one master port, data is transferred to t e slave port. Ot er master port is deactivated.
At t e same time timer starts. During timer delay, data from "first" master port are transferred to
t e slave port. Meanw ile ot er master port is not active. After timer elapses, deactivated master
port is activated again. Slave port is connected to bot master ports again. If data comes to bot
master ports simultaneously, master port 1 (p ysical port 2) as priority.
Switc time delay is set wit switc es at t e bottom of t e device. Possible timer settings are: no
delay, 20 ms, 40 ms, 60 ms, 80 ms, 0,1 s, 0,2 s, 0,3 s, 0,4 s, 0,5 s, 1s, 1,2 s, 1,5 s, 2 s, 2,5 s, 5
s.
Wide power supply voltage allows connection to all common station batteries. Additionaly it can
be also connected to standard AC voltages.
T is device is intended for use in cubicles and cabinets in all kinds of power production,
transmission and distribution stations. It requires no maintenace. All normaly used connectors,
switc es and lig t indicators are accessed at t e front side of t e device. One lig t indicator
indicates power supply voltage, ot ers indicate communication transfer.
3.2 TYPICAL APPLICATION
Device: Document: Code: Date: Page:
CMU 100 / x.1.1.1 - 17 User manual CMUMU217 03.02.2021 7
