5.2.2 Connecting the RS485
Make sure the followings when using the serial port COM1 with RS485 or COM2.
⚫ A connection condition is 1 on 1 (single point connection) or 1 on N (multi-point connection).
A maximum number of 32 SIMs are connectable in the multi-point connection.
⚫ After receiving commands, SIM will return a response approximately 5 msec later
*1
. Use the PC
of which transmit/receive switch time is 5 msec or less.
⚫ Use twisted-pair wire in communication cable. The extended communication cables should be
1.2 km or less.
⚫ Connect the terminator to the communication devises at both ends of the transmission line. The
terminator (120 Ω, 0.25 W) is required for connection.
(SCU-1601 does not have terminator setting function)
b) RS485 multi-point connection
Figure 41 - RS485 connections
*1 Software version 63_A 1.2 or later.
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