Mitsubishi Electric L02SCPU User's Manual And Reference page 227

(7) Enabling/disabling echo back of RS-422/485 adapter
When data are communicated via RS-485 (two-wire type) in the RS-422/485 adapter, the sent data can be
echoed back to the RDA and RDB of own station.
The echo back status (receiving the sent data or not (discard the data)) can be specified.
(a) Setting method
1.
Turn on SM1334 (RS-422/485 echo back specification). (Disable echo back.)
2.
The CPU module starts sending data.
(b) Precautions
• The setting of SM1334 (RS-422/485 echo back specification) is enabled when a send request is received.
Even if the setting is changed during the send processing, the change is not reflected to the operation.
• SM1334 can be set only when the RS-422/485 adapter is used.
Sending data
RS-422/485
adapter
SDA
SDB
RDA
RDB
Receives or not receive
(discards) the data.
CHAPTER 3 CPU MODULE FUNCTIONS
Target device
SDA
SDB
RDA
RDB
3
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