OPTO 22 B3000-B, Руководство пользователя

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CHAPTER 2: CONFIGURATION AND COMMUNICATION
B3000-B Serial Brains User’s Guide 5
4. Use the three termination switches to set termination as follows:
–
For all B3000-B or B3000-B-OMUX brains that are not at the physical end of
the cable, set all three of the termination switches to the OFF position.
– For the brain at the physical end of the cable, set as follows:
–
If using 2-wire RS-485, set IRQ and TX/RX ON, and set RX OFF.
– If using 4-wire RS-485, set all three of the termination switches ON.
NOTE: If your system has a controller or computer at one end of the cable, you only
need to terminate the one brain at the other end of the cable.
However, if you have brains at both ends of the cable with the controller or computer
somewhere in between, you need to terminate the brains at both ends of the cable and
turn off the termination at the controller or computer.
NOTE: Biasing is required at one location only. It can be applied anywhere on the link,
however, it is normally applied at the controller or computer. Because of this, the brain
does not offer biasing switches.
5. Use the two rotary address switches to set the brain’s address as described in the
next section.
SETTING THE ADDRESS AND COMMUNICATION OPTIONS
The brain’s address and other communication options are set using
the two 16-position rotary switches on the top of the brain—an
upper address switch and a lower address switch. Each brain
contains four addresses consisting of the base address, base +1,
base +2, and base +3. The base address is an even multiple of 4.
NOTE: The normal communication options are Binary and CRC.
The following tables show switch settings for each address.
• For Binary or ASCII, CRC16, see page 6
• For Binary or ASCII, Checksum, see page 7
ON
End of cable:
4-wire RS-485
ON
End of cable:
2-wire RS-485
ON
1
2
3
IRQ
RX
TX/RX
Not at end of cable:
switches off
IRQ
RX
TX/RX
IRQ
RX
TX/RX
1
2
3
1
2
3
Upper
address
Lower
address
8
9
A
B
C
D
E
F
7
6
5
4
3
2
1
0
Address Switch