SM_Close SM_ConfigureSerialConnection SM_ConfigureSerialTimeouts SM_CustomMessage SM_GetAnalogConfig SM_GetAnalogInputConfig SM_GetAnalogInputRanges SM_GetAnalogOutputRanges SM_GetDeviceConfig SM_GetFirmwareVersion SM_GetLastError SM_GetLastFTDIError SM_GetLastWin32Error SM_GetPIODirection SM_GetPIOPresets SM_GlobalCommsReset SM_NotifyInputState SM_NotifyOnInputChange SM_Open SM_OpenSecure SM_ReadAnalogInputs SM_ReadAnalogOutputs SM_ReadDigitalInputs SM_ReadDigitalOutputs SM_ReadPIO SM_SelectDevice SM_SetAnalogConfig SM_SetAnalogInputConfig SM_SetAnalogInputRanges SM_SetCommunications SM_SetPIODirection SM_SetPIOPresets SM_SetPolarity SM_SetSoftwareAddress SM_Version SM_WriteAnalogOutputs SM_WriteDigitalOutputs SM_WritePIO

int __stdcall SM_NotifyOnInputChange ( SM_HANDLE  handle, int  start, int  number, unsigned char *  values, int  delay, int  blocking  ) Continuously reads the discrete inputs until a change occurs. Parameters [in] handle Valid handle returned by SM_Open(). [in] start Modbus address to begin the read (zero-indexed). [in] number Quantity of inputs to read. [out] values On input change, this buffer will be populated with the input state. [in] delay Time to delay between issuing reads (ms). [in] blocking Indicates whether to wait for a change (non-zero), or immediately return control to the caller (zero). Return values 1 Input state has changed. 'Values' parameter now contains valid input state. (Blocking mode only) 0 Successful completion. -1 Invalid SeaMAX handle. -2 There is already a pending NotifyOnInputChange request. See SM_NotifyInputState() to determine it's state or to cancel it. -10 Could not read inputs. Parameters may be incorrect or the device may not be reachable, present, or may be busy. SM_NotifyOnInputChange will continuously read the inputs until a change is detected, similar to consecutive SM_ReadDigitalInputs() calls. The delay between reads is configurable based on the delay parameter. After an input change, the values parameter will be populated with the current input state. Note Only one notify request can be outstanding at a time. SM_ReadDigitalInputs() has more information on parameter values. There are two modes of operation for this function: blocking and non-blocking. If the blocking parameter is supplied as non-zero, SM_NotifyOnInputChange will not return until a input change occurs. Since blocking mode may be dangerous in instances where a logic change can not be guaranteed, a non-blocking notify request may be issued that will begin reading the inputs and terminate once canceled or a change occurs. Execution returns immediately to the caller, whereby the SM_NotifyInputState() function provides an interface to cancel the request or check on it's status. Note See the SM_NotifyInputState() function for more information on cancelling or checking the status of an outstanding request. Warning The 'values' parameter should be pre-allocated with enough bytes of space to hold 'number' bits of input states. For instance, if 12 inputs are being read, the values parameter should have 2 bytes of space allocated before calling this function. The 'values' parameter should not be accessed (read or written) until SM_NotifyInputState() indicates that the request has completed (either canceled by the user or completed due to input change). Accessing the values buffer may prevent the notify request from completing, resulting in data loss. See also SM_NotifyInputState()