5.2Serial Port

CHAPTER 5: COMMUNICATIONS

SERIAL PORT

5.2Serial Port

5.2.1 Description

This is a standard RS232 port to handle the serial messages. It has a fixed port settings of 19200, 8, N, 1. The PDU uses this port. The protocol for request and response of data is a fixed 8-byte packet. It will always start with SOH and end with a simple checksum (~sum + 1). The packets will include all the functionality found in the DeviceNet Extension object. The data is in ‘big endian’ format here (big end first: MSB-LSB). The packet is outlined below:

Bit Position

Name

 

 

Bit 7

SOH

 

 

Bit 6

Service

 

 

Bit 5

Attribute

 

 

Bit 4

Data 3

 

 

Bit 3

Data 2

 

 

Bit 2

Data 1

 

 

Bit 1

Data 0

 

 

Bit 0

Checksum

 

 

LM10 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL

5–63

Page 69
Image 69
GE LM10, Motor Protection System instruction manual Serial Port, Description