Chapter 2. API Reference
Note: The cid and param_key have to be unique. Please use the prefix to the parameter key if you have several
similar parameters in your register map table.
Table 8: Table 2 Example Register mapping table of Modbus slave
CID RegisterLengthRange TypeUnitsDescription
0 300004 MAX_UINTU32 Not
de-
fined
Serial number of device (4 bytes) read-only
1 300022 MAX_UINTU16 Not
de-
fined
Software version (4 bytes) read-only
2 400004 -20..40 FLOATDegCRoom temperature in DegC. Writing a temperature value to this register for
single point calibration.
// Enumeration of modbus slave addresses accessed by master device
enum {
MB_DEVICE_ADDR1 = 1,
MB_DEVICE_ADDR2,
MB_SLAVE_COUNT
};
// Enumeration of all supported CIDs for device
enum {
CID_SER_NUM1 = 0,
CID_SW_VER1,
CID_TEMP_DATA_1,
CID_SER_NUM2,
CID_SW_VER2,
CID_TEMP_DATA_2
};
// Example Data Dictionary for Modbus parameters in 2 slaves in the segment
mb_parameter_descriptor_t device_parameters[] = {
// CID, Name, Units, Modbus addr, register type, Modbus Reg Start Addr, Modbus␣
,→Reg read length,
// Instance offset (NA), Instance type, Instance length (bytes), Options (NA),␣
,→Permissions
{ CID_SER_NUM1, STR("Serial_number_1"), STR("--"), MB_DEVICE_ADDR1, MB_PARAM_
,→INPUT, 0, 2,
0, PARAM_TYPE_U32, 4, OPTS( 0,0,0 ), PAR_PERMS_READ_WRITE_
,→TRIGGER },
{ CID_SW_VER1, STR("Software_version_1"), STR("--"), MB_DEVICE_ADDR1, MB_PARAM_
,→INPUT, 2, 1,
0, PARAM_TYPE_U16, 2, OPTS( 0,0,0 ), PAR_PERMS_READ_WRITE_
,→TRIGGER },
{ CID_TEMP_DATA_1, STR("Temperature_1"), STR("C"), MB_DEVICE_ADDR1, MB_PARAM_
,→HOLDING, 0, 2,
0, PARAM_TYPE_FLOAT, 4, OPTS( 16, 30, 1 ), PAR_PERMS_READ_
,→WRITE_TRIGGER },
{ CID_SER_NUM2, STR("Serial_number_2"), STR("--"), MB_DEVICE_ADDR2, MB_PARAM_
,→INPUT, 0, 2,
0, PARAM_TYPE_U32, 4, OPTS( 0,0,0 ), PAR_PERMS_READ_WRITE_
,→TRIGGER },
{ CID_SW_VER2, STR("Software_version_2"), STR("--"), MB_DEVICE_ADDR2, MB_PARAM_
,→INPUT, 2, 1,
0, PARAM_TYPE_U16, 2, OPTS( 0,0,0 ), PAR_PERMS_READ_WRITE_
,→TRIGGER },
{ CID_TEMP_DATA_2, STR("Temperature_2"), STR("C"), MB_DEVICE_ADDR2, MB_PARAM_
,→HOLDING, 0, 2,
(continues on next page)
Espressif Systems 625
Submit Document Feedback
Release v4.4
To Next Page
Loading...