GE 369 User Manual

CG40 369 MOTOR MANAGEMENT RELAY – COMMUNICATIONS GUIDE
MODBUS RTU PROTOCOL CGCOMMUNICATIONS GUIDE
If an 369 Modbus slave device receives a transmission in which an error is indicated by the
CRC-16 calculation, the slave device will not respond to the transmission. A CRC-16 error
indicates than one or more bytes of the transmission were received incorrectly and thus
the entire transmission should be ignored in order to avoid the 369 performing any
incorrect operation.
The CRC-16 calculation is an industry standard method used for error detection. An
algorithm is included here to assist programmers in situations where no standard CRC-16
calculation routines are available.
5.4 CRC-16 Algorithm
Once the following algorithm is complete, the working register "A" will contain the CRC
value to be transmitted. Note that this algorithm requires the characteristic polynomial to
be reverse bit ordered. The MSbit of the characteristic polynomial is dropped since it does
not affect the value of the remainder. The following symbols are used in the algorithm:
--> data transfer
A 16 bit working register
AL low order byte of A
AH high order byte of A
CRC 16 bit CRC-16 value
i, j loop counters
(+) logical exclusive or operator
Di i-th data byte (i = 0 to N-1)
G 16 bit characteristic polynomial = 1010000000000001 with MSbit
dropped and bit order
reversed
shr(x) shift right (the LSbit of the low order byte of x shifts into a carry flag, a '0'
is shifted into the
MSbit of the high order byte of x, all other bits shift right one location
The algorithm is as follows:
1. FFFF hex --> A
2. 0 --> i
3. 0 --> j
4. Di (+) AL --> AL
5. j+1 --> j
6. shr(A)
7. is there a carry? No: go to 8.
Yes: G (+) A --> A
8. is j = 8? No: go to 5.
Yes: go to 9.
9. i+1 --> i
10. is i = N? No: go to 3.
Yes: go to 11.
11. A --> CRC

GE 369 Specifications

General

Current Rating	5A
Frequency	50/60 Hz
Mounting	Panel Mount
Protection Functions	Overcurrent, Undervoltage
Type	Digital protective relay
Operating Temperature	-20°C to 60°C

Summary

Overview

Electrical Interface

Describes the physical connections and wiring for communication interfaces.

Profibus Communications

Details support for Profibus-DP and Profibus-DPV1 protocols.

DeviceNet Communications

Outlines support for the optional DeviceNet communication protocol.

Modbus Communications

Explains the implementation of the Modbus RTU serial communication standard.

Modbus/TCP Communications

Covers the Modbus/TCP option for Ethernet network connections.

Profibus-DP Communications

Profibus Communication Options

Lists supported Profibus-DP and Profibus-DPV1 interfaces and GSD files.

369 Relay Profibus-DP Parameterization

Describes the relay's mandatory parameterization and setup tools.

369 Relay Profibus-DP Configuration

Explains basic Profibus-DP configuration, bus addressing, and connection.

369 Relay Profibus-DP Diagnostics

Details standard and specific diagnostic data for Profibus-DP.

369 Relay Profibus-DP Loss Of Communication Trip

Explains the feature to trip relays upon loss of Profibus communication.

Profibus-DPV1 Communications

369 Relay Profibus-DPV1 Parameterization

Describes DPV1 parameterization and enabling acyclical functionality.

369 Relay Profibus Configuration

Covers basic Profibus-DPV1 configuration and bus addressing.

369 Relay Profibus Input Data

Details configuring data made available through Profibus Input Data.

369 Relay Profibus Output Data

Explains the capability to force output relay states via cyclic data.

369 Relay Profibus Diagnostics

Refers to diagnostic data tables for Profibus-DPV1 option.

369 Relay Profibus-DPV1 Acyclical Communication

Describes data access using "slot and index" addressing for DPV1.

DeviceNet Protocol

DeviceNet Communications

Details the DeviceNet protocol as a group 2 server, MAC ID, and baud rate.

Poll Data

Explains polling function, control data, and data groups.

Change of State (COS)

Describes COS data as per class 4, instance 66h, attribute 3.

Identity Object (class code 01h)

Details the Identity Object (Class code 01h) and its services.

Message Router (class code 02h)

Explains the Message Router object for addressing services within the device.

DeviceNet Object (class code 03h)

Details the DeviceNet Object (Class code 03h), its attributes, and services.

Assembly Object (class code 04h)

Covers the Assembly Object (Class code 04h), its services, and attributes.

DeviceNet Connection Object (class code 05h)

Describes connection objects for explicit and polled connections.

Acknowledge Handler Object (class code 2Bh)

Details the Acknowledge Handler Object (Class code 2Bh) and its services.

I/O Data Input Mapping Object (class code A0h)

Explains the I/O Data Input Mapping Object for data input configuration.

I/O Data Output Mapping Object (class code A1h)

Details the I/O Data Output Mapping Object for data output configuration.

Parameter Data Input Mapping Object (class code B0h)

Covers the Parameter Data Input Mapping Object for parameter data.

DeviceNet Data Formats

Explains various data formats used in DeviceNet communication.

Modbus RTU Protocol

Data Frame Format and Data Rate

Describes the Modbus RTU data frame structure and supported baud rates.

Data Packet Format

Details the structure of Modbus request and response data packets.

Error Checking

Explains the CRC-16 error checking mechanism for Modbus.

CRC-16 Algorithm

Provides the algorithm for calculating CRC-16 for error detection.

Timing

Discusses timing constraints for data packet synchronization.

Supported Modbus Functions

Lists the Modbus functions supported by the 369 relay.

Error Responses

Describes the types of error responses sent to the master.

Modbus Commands

Details specific Modbus commands for controlling the relay.

Memory Map

Memory Map Information

Explains how data is stored and addressed in the relay's memory.

User Definable Memory Map Area

Describes the feature allowing custom mapping of data registers.

Event Recorder

Details the relay's event recording capabilities and data access.

Waveform Capture

Explains the waveform capture feature and how to access stored data.

Motor Start Data Logger

Describes the data logging for motor starts and recorded parameters.

Data Logger

Details the data logger's capabilities, storage, and access methods.

Modbus Memory Map

Introduces the Modbus memory map structure and address organization.