CMU 100 - RS485 to 2x RS232 fallback switch
3 RS485 TO 2x RS232 FALLBACK SWITCH
3.1 DESCRIPTION
Fallback switch is communication device that switches data between two master ports and one
slave port. It is intended to connect one device (RTU) to two master devices (PC).
This device contains one RS485 interface (master) and two RS232 interfaces two (slave) ports.
When data comes to one master port, data is transferred to the slave port. Other master port is
deactivated. At the same time timer starts. During timer delay, data from "first" master port are
transferred to the slave port. Meanwhile other master port is not active. After timer elapses,
deactivated master port is activated again. Slave port is connected to both master ports again. If
data comes to both master ports simultaneously, master port 1 (physical port 2) has priority.
Switch time delay is set with switches at the bottom of the 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.
This 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,
switches and light indicators are accessed at the front side of the device. One light indicator
indicates power supply voltage, others indicate communication transfer.
3.2 TYPICAL APPLICATION
Device:
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Code:
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User manual CMUMU511
7
Picture 2: CMU 100 / x.5.1.1 - 17 typical application
