Serial Port; Description - GE LM10 Instruction Manual

CHAPTER 5: COMMUNICATIONS
5.2

Serial Port

5.2.1

Description

LM10 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL
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
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
Name
SERIAL PORT
5–63