It may be desirable to change the word or byte order of objects when the SCADAPack is acting as a Modbus RTU Server or Modbus TCP Server. This mainly concerns Modbus floating point and signed/unsigned Modbus double registers.
This is accomplished in the Modbus -> Server -> Advanced Configuration of RemoteConnect
| Parameter | Parameter Description | Setting | Setting Description |
| Byte Ordering for 32-bit Values | Determines how UDINT, DINT, and REAL data from objects is converted into Modbus register data. The setting configures the order of the bytes for register values received or sent by a Modbus RTU Server or Modbus/TCP Server. Select the byte order and word order combination that matches the order expected by the Modbus RTU Client or Modbus/TCP Client that is polling the RTU. The order you select is used for 32-bit register values. ·2 bytes (1 word) are contained in the first register, and 2 bytes (1 word) are contained in the second | High byte/Low word first (3412) High byte/High word first (1234) Low byte/High word first (2143) Low byte/Low word first (4321) | The numbers 1, 2, 3, and 4 represent the 4 bytes in a 32-bit register value. ·High byte/Low word first o Sends 32-bit values in byte order 3412 o Default setting o Select this setting to emulate SCADAPack 300E RTUs ·High byte/High word first o Sends 32-bit values in byte order 1234 o Default setting if Realflo is enabled o Select this setting to emulate SCADAPack 32 and SCADAPack 300 RTUs ·Low byte/High word first o Sends 32-bit values in byte order 2143 ·Low byte/Low word first o Sends 32-bit values in byte order 4321 |
| Swap Word Order for 32-bit Integers | Telepace firmware has a different word order for floats and long integers. A SCADAPack x70 device replacing a SCADAPack 3xx or 32 needs to behave in the same way. This setting defines if the 4 byte long integer data needs to be word swapped. This only happens for 32 bit long integer values, not for floats. For example, a configured byte order 1234 becomes 3412 for long integers only. | No Yes | ·No o Long integers have the same byte order as floats o Default setting for newly created projects with Realflo disabled o Select this setting to emulate SCADAPack 32 and SCADAPack 300 RTUs with ISaGRAF firmware o Select this setting to emulate SCADAPack 300E RTUs ·Yes o Words for long integers are swapped o Default setting for newly created projects with Realflo enabled o Select this setting to emulate SCADAPack 32 and SCADAPack 300 RTUs with Telepace firmware |
