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TORRIX RS485 Modbus

TORRIX RS485 Modbus
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Technical Documentation TORRIX RS485 with MODBUS Protocol

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Supported MODBUS Protocol Variants TORRIX-RS485 with Modbus protocol only supports the Modbus ASCII variant as described in the Modicon Modbus Protocol Reference Guide. Wiring Connections The wiring of the level sensors TORRIX RS485 may only be carried out with the power disconnected. For wiring, proceed as follows: • If not already connected, plug the coupling of the FAFNIR connection cable onto the M12 connector of the sensor head. First tighten the union nut of the M12 connector by hand and then use an open-ended spanner to tighten the nut further 180°. The tightening torque should be...

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2 MODBUS Register Map Supported Function Codes The following function codes are supported: • Function Code 03 - Read Holding Registers • Function Code 04 - Read Input Registers • Function Code 08 - Diagnostics (only sub-function 00 - Return Query Data) All registers are read only. Support of different output formats The following output formats are supported: 16 bit unsigned integer • Big Endian (most significant byte first): [12] • Little Endian (least significant byte first): [21] 32 bit floating point • Big Endian (straight word order, most significant byte first): [12] [34] •...

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Values Probe type • 1 = Basic Number of discrete temperature sensors The number of discrete temperature sensors depends on the probe type. Status of probe The probe can be in one of the following states: • 0 = ok

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2.2 Values formatted in 32 bit floating point format The values formatted according to the IEEE 754 single-precision 32 bit floating point format can be read out using the following two Function Codes: • Function Code 03 - Read Holding Registers • Function Code 04 - Read Input Registers You have to add 30001 or 40001 to the address shown in the table to get the register number. Please take into account that the address shown in the table has a hexadecimal format while the register number has a decimal format. Two consecutive 16 bit registers have to be read to get the complete 32 bit...

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* Only available if the probe is of type Advanced or Flex. ** Only available if the probe is of type Advanced.

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32-Bit Floating Point, Measurement Units: US (inch, °F) * Only available if the probe is of type Advanced or Flex. ** Only available if the probe is of type Advanced.

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FAFNIR 2.3 Exception Codes The following exception codes are supported: • 01 - Illegal Function • 02 - Illegal Data Address • 03 - Illegal Data Value 01 - Illegal Function The exception code Illegal Function is returned under the following circumstances: • A function code other than 03 ,04 or 08 is used • The function code 08 is used with a sub-function code other than 0000 02 - Illegal Data Address The exception code Illegal Data Address is returned under the following circumstances: • The function code 03 or 04 is used with a starting address that is not included in the TORRIX...

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3 Appendix3.1 Request and Response Formats Requests and Responses for Function Codes 03 and 04 Request * Number of Registers is the number of registers requested and has to be in the range of 1 to 30 ** Byte Count is the number of bytes (not registers) returned *** see Appendix LRC Calculation

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The LRC of a message has to be calculated as follows: 1. Sum up all bytes of the message, excluding the starting character {:} and the ending characters {cr} and {lf}. The sum is build up in a one-byte field, so all carries will be discarded. 2. Calculate the ones-complement of the sum by subtracting the sum from 0xFF. 3. Calculate the twos-complement of the sum by adding 0x01 to the ones-complement of the sum. This example shows how the LRC of the complete message {:}010300200006D6{cr}{lf} has to be calculated. Note: • control characters of the message shown in brackets • LRC of the...

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3.3 Communication Examples Read the serial number of the probe The serial number is available in the register pairs 0x0000/0x0001 (Big Endian) and 0x0100/0x0101 (Little Endian). Reading the serial number in Big Endian format from a probe with slave address 1 using Function Code 03 looks like this: Request: {:}010300000002FA{cr}{lf} Response: {:}010304000186ABC6{cr}{lf} Evaluation: Register 0x0000 = 0x0001 Register 0x0001 = 0x86AB O Serial number = 0x000186AB = 100011 Read all static values of the probe Reading all static values in Big Endian format from a probe with slave address 1 using...

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• 0x0620/0x0621 - format [43][21], Little Endian, Bytes Swapped • 0x0720/0x0721 - format [34][12], Little Endian Reading the level of product from a probe with slave address 1 in metric units and format [43][21] (Little Endian, Bytes Swapped) using Function Code 04 looks like this: Request: {:}010402200002D7{cr}{lf} Response: {:}010404BC942B4438{cr}{lf} Evaluation: Register 0x0220 = 0xBC94 Register 0x0221 = 0x2B44 O Level of product = 0x442B94BC = 686,324 mm Read level of product, level of water and average temperature The level of product is available as 32-bit floating point...

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