IDEC MICROSmart FC6A-C16K1CE, Руководство по связи, Страница: 97 / 252

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OMMUNICATION
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ANUAL
FC9Y-B1730 5-21
5: U
SER
C
OMMUNICATION
I
NSTRUCTIONS
D1 (Destination 1)
Set an internal relay or an output for the receive completion output.
When the start input for a RXD instruction is turned on, preparation for receiving data is initiated, followed by data conversion and
storage. When the data receive operation sequence
is complete, the designated output or internal relay is turned on.
Conditions for Completion of Receiving Data
After starting to receive data, the RXD instruction can be completed in three ways depending on the designation of end delimiter and delimiter in the receive format.
Note: Whenever a receive timeout has occurred, data receiving stops arbitrarily.
Data receiving is complete when one of the above three conditions is met. To abort a RXD instruction, use the special internal relay for user
communication receive instruction cancel flag. See "User Communication Receive Instruction Cancel Flag" on page 5-22.
Example: A RXD instruction does not have an end delimiter and has a delimiter programmed in the receive format for data registers.
D2 (Destination 2)
Set the data register in which to store the receive status and the receive data byte count.
The receive status is stored in D2+0 and the receive data byte count is stored in D2+1.
Data registers D0000 through D7998 and D10000 through D55998 can be set.
D2+0 (Receive Status)
The receive status is stored in the data register set with D2. The receive status includes the reception operation status and the
error information.
If the receive status code is other than shown above, a receive instruction error is suspected. See "User Communication Error" on
page 5-43.
D2+1 (Receive Digits (Bytes))
The data register next to the device designated for receive status stores the byte count of data received by the RXD instruction.
When a start delimiter, end delimiter, and BCC are included in the received data, the byte counts for these codes are also included
in the receive data byte count.
Example: Data register D200 is designated as a device for receive status.
End Delimiter Delimiter Conditions for Completion of Receiving Data
With With or Without
When a specified byte count of data (digits
×
repeat) has been received or when an end delimiter is received.
When a BCC exists immediately after the end delimiter, the BCC is received before ending data receiving.
Without With
After the last constant (including delimiter) designated in the RXD instruction has been received, data
receiving is completed when the subsequent byte count of data has been received.
Without Without When a specified byte count of data (digits × repeat) has been received.
Receive Format
DR1 FFh BCC
1 byte 4 bytes max. + delimiter 1 byte 2 bytes max.
DR2
Delimiter: FFh
Conversion: ASCII to Binary
Digits: 4
Repeat: 1
Delimiter: —
Conversion: None
Digits: 2
Repeat: 1
After delimiter FFh has been received, data receiving is
completed when subsequent 3 bytes are received.
Receive Status Code Status Description
16 Preparing data receive
From turning on the start input for a RXD instruction to read the receive format, until
the RXD instruction is enabled by an END processing
32 Receiving data From enabling the RXD instruction by an END processing, until incoming data is received
48 Data receive complete
From receiving incoming data, until the received data is converted and stored in data
registers according to the receive format
64 Receive instruction complete All data receive operation is completed and the next data receive is made possible
128
User communication receive
instruction cancel flag active RXD instructions are cancelled by special internal relay for user communication
receive instruction cancel flag, such as M8022, M8023 or M8026
D200
Receive status
D201
Receive data byte count