GE LM10, Motor Protection System instruction manual Serial Port, Description

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