Article - CS299224

Modbus device readings show wrong values in PTC Kepware Products

Modified: 15-Apr-2025   


Applies To

  • Kepware Server (formerly KEPServerEX) 5.20.396.0 to 6.17
  • ThingWorx Kepware Server (legacy) 8.0 to 6.17

Description

  • Modbus device readings show wrong values in KEPServerEX / ThingWorx Industrial Connectivity / ThingWorx Kepware Server
  • Read value with more than 16 bit word or dword shows wrong result
  • How to swap word order in float reading
  • Modbus TCP/IP Ethernet register shows different value than expected
  • Modbus shows different values in QuickClient than expected
  • How does one change the byte swapping and endianness of a modbus tag within a device?
  • The values I read from KepWare do not match the values on the PLC using Modbus TCP/IP Ethernet driver
  • Float values not read correctly while other applications like Modbus View can read them as reverse Float 
  • Modscan data seemed to have been aligning actual data but not Kepware Server data
  • Modbus float value is not showing correctly and need assistance to fix this
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