What is meant by Command Word (HSO2) and Status Word (HSI1)?

When you are trying to send a command to the unit through the mapping, you will be using HSO2 for most of these commands.  
HSI1 is a status word that indicates the state of the unit at that time.  Do not confuse this with HSO1 which is the status of the command sent in HSO2.
If you are monitoring HSI1, this would indicate the condition of the unit at all times.  Any conditions in the list will have its bit turned on, so the value would be a combination of any bits turned on at that time.  Bits 0 & 1 are for A/D error/fault conditions.  If you have a problem with the input from the load cells or have a problem with the A/D converter in the unit, you will get one or both of these bits on.  
If the bit is 0, then it is not an active condition, 1 would indicate a true condition.
HSI1 - Status Word:

• HSI1 bit 0 (HI1.0) - A/D Conversion Error
• HIS1 bit 1 (HI1.1) - A/D Failure
• HIS1 bit 2 (HI1.2) - Center of Zero
• HIS1 bit 3 (HI1.3) - Weight Overrange
• HIS1 bit 5 (HI1.5) - Real Time Clock failure
• HIS1 bit 6 (HI1.6) - Motion
• HIS1 bit 8 (HI1.8) - SD memory card read failure
• HIS1 bit 9 (HI1.9) - Display error
• HIS1 bit 11 (HI1.11) - SD memory card write failure

When you send a command by setting a bit in HSO2, the command word, the module will run that command and send a copy of the command bit sent back to the user in HSO2 being read.  At that time, the unit will also send a command status in HSO1 to give an indication of a pass or fail of the command.  If it fails, the value returned will be an indication of the cause of the failure.  HSO1 - Command Status - value returned after a command (see HSO2) is done. Non-zero status means the command failed

• • Status 1 (0x0001) = Calibration, Zero, or Tare failed due to ADC error
  • Status 2 (0x0002) = Calibration, Zero, or Tare failed due to ADC failure
  • Status 64 (0x0040) = Calibration, Zero, or Tare failed due to Motion
  • Status -8 (0xFFF8) = Hard Calibration failed, not enough ADC counts between high and low steps
  • Status -6 (0xFFFA) = C2 Calibration failed, no C2 sensors detected
  • Status 7 (0x0007) = Bad command number or no command being sent
• HSO2 - Command Word. Commands are performed on a 1-shot basis when this word changes from 0 to 1. An error code is returned in the "command status" word HSO1.
  • HSO2 bit 0 (HO2.0) - Tare
  • HSO2 bit 1 (HO2.1) - Zero
  • HSO2 bit 2 (HO2.2) - Hard Cal Low
  • HSO2 bit 3 (HO2.3) - Hard Cal High
  • HSO2 bit 4 (HO2.4) - C2 Cal
  • HSO2 bit 5 (HO2.5) - Write Parameters to SD card
  • HSO2 bit 6 (HO2.6) - Print
  • HSO2 bit 7 (HO2.7) - Clear Tare