Page 382 - Gas Detection Systems Training Manual

Response
Here is an example of a response to the query on the previous page:
Write Multiple Holding Registers Response
Field Name
Slave Address Function Code Address High Address Low Item Count High Item Count Low CRC Low Byte CRC High Byte
Example (Hex)
11 10 08 46 00 03 61 2D
If the register address in the query is not valid for a multiple register write function, the SEC 3120 unit will issue an Exception 2 as a response. If the multiple register write enable password register in the query did not include the proper password, the SEC 3120 unit will issue an Exception 8 as a response. If the SEC 3120 unit is not operating in identical sensor role mode, and an attempt to write to ALL sensors (address range 42001 to 42100, except 42011- Zone ID & 42040- Self Test) it will generate an Exception 3 response.
Response Exception 2
Field Name
Slave Address Function Code Exception Code CRC Low Byte CRC High Byte
Example (Hex)
01 86 02 C3 A1
Response Exception 3
Field Name
Slave Address Function Code Exception Code CRC Low Byte CRC High Byte
Example (Hex)
01 86 03 02 61
Response Exception 8
Field Name
Slave Address Function Code Exception Code CRC Low Byte CRC High Byte
Example (Hex)
01 86 08 43 A6
SEC 3120 16-bit Modbus Manual Page 42 Of 46 Sensor Electronics Corporation For Version 1.2 and above December 2012 P/N 1580282, Rev. 1, 20121228