func (this ModbusRTUConnection) ReadInputRegisters(slave int8, startAddr int, nb int) ([]uint16, error) {
if C.modbus_set_slave(this.ctx, C.int(slave)) != 0 {
return nil, errors.New(fmt.Sprintf("Invalid slave id %d", slave))
}
var space [65535]C.uint16_t
this.ProcessHook(RTU_03_LEN)
if ressived := C.modbus_read_input_registers(this.ctx, C.int(startAddr),
C.int(nb), &(space[0])); int(ressived) != nb {
if ressived == -1 {
errno := C.getErrno()
if errno == C.EMBMDATA {
return nil, errors.New(C.GoString(C.modbus_strerror(errno)))
}
return nil, errors.New(fmt.Sprintf("Unknown modbus error errno=%d", errno))
} else if ressived == 0 {
return nil, errors.New("No ansver ressived")
}
} else {
result := make([]uint16, ressived)
for i := 0; i < int(ressived); i++ {
result[i] = uint16(space[i])
}
return result, nil
}
return nil, nil
}
// The modbus_read_input_registers() function shall read the content of the nb input registers to address addr of the remote device. The result of the reading is stored in dest array as word values (16 bits).
// You must take care to allocate enough memory to store the results in dest (at least nb * sizeof(uint16_t)).
// The function uses the Modbus function code 0x04 (read input registers). The holding registers and input registers have different historical meaning, but nowadays it’s more common to use holding registers only.
func (this *RtuConnection) Read_input_registers(addr int, nb int) ([]uint16, error) {
ioresult := make([]C.uint16_t, nb)
res, errno := C.modbus_read_input_registers(this.ctx, C.int(addr), C.int(nb), &ioresult[0])
if int(res) == nb {
result := make([]uint16, int(res))
for i := 0; i < int(res); i++ {
result[i] = uint16(ioresult[i])
}
return result, nil
} else {
return nil, errors.New(modbus_strerror(errno))
}
}
