IDEC FT1A-B12RA, User Manual

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ANUAL
FT9Y-B1378 11-3
11: M
ODBUS
C
OMMUNICATION
Communication Error Data
When Error Status is configured in the Request Table from the Function Area Settings, the error data of each request can be
confirmed.
Communication Error Data of Each Request
Error data of each request in the entire request table can be confirmed. To confirm error data of each request, select to use Error
Status in the Request Table from the Function Area Settings and enter the data register number.
When Use a single DR for all communication requests is not selected, starting with the data register number, data registers as
many as the quantity of requests are reserved for storing error data. When an error occurs for a request, an error code is stored to
a corresponding data register.
When Use a single DR for all communication requests is selected, the same data register is shared by all requests. When an error
occurs for a request, an error code is stored to the data register and the old value is overwritten.
Number of Requests in Modbus Master
The number of requests that can be programmed in a request table is shown in the table below:
Note: 8 bytes of the user program area are needed per each request.
Use a single DR for all
communication requests
Error data of each communication request
Unchecked
Error data, the remote host number (high-order byte) and error code (low-order byte), of each request in the
entire request table can be confirmed. Data registers as many as the quantity of requests are reserved for
storing error data. When an error occurs for a request, error data is stored to the corresponding data register.
Checked
A single data register is shared by all requests. When an error occurs for a request, error data is stored to the
data register and the old error data is overwritten.
Bit Allocation
Remote Host Number
(high-order byte)
1 to 255
Error Code
(low-order byte)
00h: Normal completion
01h: Function code error (unsupported function code)
02h: Access destination error (address out of range, device quantity out of range)
03h: Device quantity error, 1-bit write data error (specified device quantity of 1-bit write is unsupported)
12h: Frame length error (frame length of transmitted request exceeds range)
13h: BCC error (BCC does not match)
14h: Slave number error (received slave number is invalid)
16h: Timeout error (timeout occurs)
Port Port 2 and Port 3
No. of requests 255