• Serial Communications Technical Manual
  A short manual covering the basic fundamentals of serial communications.

• RC900 Data Communications Manual (98fe_a.pdf)
  A comprehensive manual covering the basic fundamentals of serial communications for the RC900 (981S).

• Troubleshoot RC900 Serial 232 Data Communications PowerPoint
  A short PowerPoint presentation covering  basic fundamentals of the serial communications hardware & software set-up for the RC900 (981S) controller.

• Free Power Point 2003 Viewer Utility (1.86MB)
  A free PowerPoint viewer software utility program for viewing PPT presentations downloaded from this web site.

• Watlow Comm7 Utility Software (2.6M) DOWNLOAD 
  Comm7 is a Windows-based diagnostic utility created by Watlow. Comm7 can be used to upload/download controller configurations or log data to a text file via RS-232.
  (Windows 3.x/95/98/XP). You can also download an older version, Comm6 HERE

• Modbus Protocol Reference Guide
  An introduction to Modbus RTU serial communications protocol.

• Modbus RTU Protocol Programming in Visual Basic (Self-Extract Zip File 61 KB)
  The Modbus Communications Example demonstrates the sort of routines necessary to communicate to a temperature controller through the Modbus protocol using a program written in Visual Basic.

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