Difference between revisions of "Protocols - Overview"

Revision as of 04:43, 21 September 2014

A protocol describes the packetization and method for moving data back and forth across that physical layer. SHIP supports three protocols, though not all protocols are supported across all available physical layers on a SIM:

• the new Raw protocol starting in SHIP v5.0.126
• the Modbus protocol, including RTU and ASCII, Master and Slave
• the upcoming SHIPBridge protocol in SHIP v5.0.200

Raw Protocol

The Raw protocol was made available starting in SHIP v5.0.126 , and enables simple movement of the following data types:

• Boolean (as Byte 0x00 or 0x01)
• Byte
• Short (16-bit)
• Integer (32-bit)
• Float (single precision, 32-bit)
• String (null terminated)

There is no packetization, framing, or checksums/CRC calculations performed on the data. The protocol, therefore, is very simple to interpret and generate on an attached device, however is susceptible to errors and misalignment over time and should only be used in some applications.

Resources:

• Raw protocol detailed description
• AN0504 - The Raw Communications Protocol (video application note)

Modbus Protocol

Bridge Protocol