int __stdcall SM_ReadHoldingRegisters	(	SM_HANDLE	handle,
		int	start,
		int	number,
		unsigned char *	values
	)

Reads a 16-bit value from the Sealevel I/O device, depending on the model.

Parameters

[in]	handle	Valid handle returned by SM_Open().
[in]	start	Modbus address to begin the read (zero-indexed).
[in]	number	Quantity of holding registers to read.
[out]	values	Register state values.

Return values

>=0	Number of bytes successfully returned in result array.
-1	Invalid SeaMAX handle.
-2	Connection is not established. Check the provided Connection object state.
-3	Read error waiting for response. Unknown Modbus exception.
-4	Illegal Modbus Function (Modbus Exception 0x01).
-5	Illegal Data Address (Modbus Exception 0x02).
-6	Illegal Data Value (Modbus Exception 0x03).
-7	Modbus CRC was invalid. Possible communications problem.

This function performs different tasks depending on the model of Sealevel I/O device. For more information, see

Note: Modbus holding registers are 16-bit wide registers. Therefore, each read will result in 2 bytes in the result array. For multi-register reads, the high-order byte will reside in the first byte (result[0]) with the lower-order byte residing thereafter (result[1]). Other register bytes subsequently follow the same pattern.

Warning: The result array parameter should have enough allocated space, before calling this method, to hold 2 bytes for every register requested.