Fault Codes
Fault codes are encoded using a standard table to allow standard Toshiba fault codes to be generated from the readback value. The no fault value is 255.
Special fault codes generated by the RTD are as follows:
| Code Value | Meaning |
| 0 | Waiting for data |
| 255 | No Fault |
| 14384 | (80) Group Fault, timeout on no units found |
| 14388 | (84) Unit Missing, reported if unit data previously observed |
Above faults 80 and 84 are reported when no data is exchanged between the indoor unit and the RTD interface even though unit data was previously observed.
*Note that the same code values are also listed in Toshiba's Fault code map and signal a unit fault. Hence, as long as data is exchanged between indoor unit and the RTD interface then the fault code values (14384 and 14388) signal the indoor unit's malfunction.
All other codes are Toshiba fault codes (RTD interfaces do not block any Toshiba fault codes). See the full table of fault code values in the attachment (only available in PDF format) below. If you require a translation, please contact Toshiba Technical Support for the translated fault codes list.
Fault code calculation
Fault codes returned from a Modbus Input register are 16 bit values. The fault code is encoded in the 16 bit value by encoding the two 8 bit fault characters in the high and low byte parts of the 16 bit value. The high byte represents an ASCII text character and the low byte is a decimal value in the range 0 to 31. The low byte value is written as two digits, so e.g. 9 is written as 09.
| 16 Bit Register Value | |||||||||||||||
| 15 | 8 | 7 | 0 | ||||||||||||
Take High and Low Bytes:
| 8 Bit High Byte | |||||||
| 15 | 8 | ||||||
and
| 8 Bit Low Byte | |||||||
| 7 | 0 | ||||||
And calculate the corresponding ASCII value:
| ASCII Character 1 | Decimal Value |
Example:
A fault code value of 17668 is returned.
HighByte(17668) = 69 = ASCII Character ‘E’
LowByte(17668) = 4 = Decimal Value ‘04’
Fault Code: ‘E04’