Edwards STP-iXL455

STP-iX455/iXL455 Series Instruction Manual
9-3
Operation
9.2.2 Connecting the RS485
Make sure the followings when using the serial port COM1 with RS485.
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.
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
(the STP pump does not have terminator setting function) .
PC
7 (D–)
8 (D+)
120
Ω
120
Ω
SIM
(Connector X3)
a) RS485 Single Point Connection
PC
7 (D–)
8 (D+)
120
Ω
7 (D–)
8 (D+)
120
Ω
7 (D–)
8 (D+)
SIM 1
(Connector X3)
SIM 2
(Connector X3)
SIM N
(Connector X3)
b) RS485 Multi-point Connection
Figure 9.2 RS485 Connections