Rockwell Automation 1788-CNCHKR User Manual

User Manual

ControlNet NetChecker

Catalog Number

Topi c Pag e

Important User Information 2

European Communities (EC) Directive Compliance 3

Additional Resources 3

Product Overview 4

Diagnostic Mode 7

Bargraph Mode 9

Operation 11

Reporting Examples 17

Additional Tips 20

Wave form Exam ples 21

1788-CNCHKR

2 ControlNet NetChecker

Important User Information

Solid-state equipment has operational characteristics differing from those of electromechanical equipment. Safety Guidelines for the Application, Installation and Maintenance of Solid State Controls (publication SGI-1.1 sales office or online at http://www.rockwellautomation.com/literature/ equipment and hard-wired electromechanical devices. Because of this difference, and also because of the wide variety of uses for solid-state equipment, all persons responsible for applying this equipment must satisfy themselves that each intended application of this equipment is acceptable.

In no event will Rockwell Automation, Inc. be responsible or liable for indirect or consequential damages resulting from the use or application of this equipment.

The examples and diagrams in this manual are included solely for illustrative purposes. Because of the many variables and requirements associated with any particular installation, Rockwell Automation, Inc. cannot assume responsibility or liability for actual use based on the examples and diagrams.

No patent liability is assumed by Rockwell Automation, Inc. with respect to use of information, circuits, equipment, or software described in this manual.

Reproduction of the contents of this manual, in whole or in part, without written permission of Rockwell Automation, Inc., is prohibited.

Throughout this manual, when necessary, we use notes to make you aware of safety considerations.

WARNIN G: Identifies information about practices or circumstances that can cause an explosion in a hazardous environment, which may lead to personal injury or death, property damage, or economic loss.

available from your local Rockwell Automation

) describes some important differences between solid-state

ATTENTION: Identifies information about practices or circumstances that can lead to personal injury or death, property damage, or economic loss. Attentions help you identify a hazard, avoid a hazard and recognize the consequences.

SHOCK HAZARD: Labels may be on or inside the equipment, for example, a drive or motor, to alert people that dangerous voltage may be present.

BURN HAZARD: Labels may be on or inside the equipment, for example, a drive or motor, to alert people that surfaces may reach dangerous temperatures.

IMPORTANT Identifies information that is critical for successful application and understanding of the product.

Rockwell Automation Publication 1788-UM001B-EN-P - August 2012

ControlNet NetChecker 3

European Communities (EC) Directive Compliance

If this product has the CE mark, it is approved for installation within the European Union and EEA regions and has been designed and tested to meet the following directive.

EMC Directive

This product is tested to meet the Council Directive 89/336/EC Electromagnetic Compatibility (EMC) by applying the following standards, in whole or in part, documented in a technical construction file:

• EN 50081-2 EMC—Generic Emission Standard, Part 2—Industrial Environment

• EN 50082-2 EMC—Generic Immunity Standard, Part 2—Industrial Environment

This product is intended for use in an industrial environment.

Additional Resources

These documents contain additional information concerning related products from Rockwell Automation.

Resource Description

Industrial Automation Wiring and Grounding Guidelines, publication 1770-4.1

Product Certifications website, http://www.ab.com

Provides general guidelines for installing a Rockwell Automation industrial system.

Provides decl arations of conformit y, certific ates, and other certif ication details.

You can view or download publications at http://www.rockwellautomation.com/literature/ To order paper copies of technical documentation, contact your local Allen-Bradley distributor or Rockwell Automation sales representative.

Rockwell Automation Publication 1788-UM001B-EN-P - August 2012

4 ControlNet NetChecker

Product Overview

The 1788-CNCHKR NetChecker is a hand-held tool for testing active ControlNet networks. It is pocket-sized and battery-powered for field use. The NetChecker helps commissioning and troubleshooting ControlNet installations by verifying signals on the ControlNet cabling. For example, installers are able to find shorts and termination faults by using the NetChecker. The tool is designed to evaluate the quality of the signal on the coaxial medium. It does not interpret the content of messages, except for the addresses of the nodes issuing messages.

The NetChecker checks several electrical characteristics of the signal:

• Level of distortion

• Noise or signal reflections

• Rising and falling edges

• Minimum message duration

• Minimum between-message duration

• Peak-to-peak amplitude

• Violations to Manchester signal encoding

An evaluation of the signal quality is made using a combination of criteria on all the above characteristics. Most of the criteria used are fixed by design and therefore cannot be modified by the user. The input signal from the network is converted to a 2-level digital signal using a voltage reference. This voltage reference (or threshold) is the only criteria that can be modified by the user by means of a slide switch (SW3). The results of the signal analysis are displayed by bi-color status indicators.

Additional features include a Node Finder and an oscilloscope output. The Node Finder detects the presence of a given node on the network. The user enters the node address on thumbwheel switches. The oscilloscope output provides a trigger and an electrically isolated network signal for displaying messages from a specified node on an oscilloscope.

The NetChecker is designed to be connected to a network via either a standard tap or the provided BNC T and cable. The NetChecker is a passive instrument. It does not send any signal on the network under test.

Rockwell Automation Publication 1788-UM001B-EN-P - August 2012

ControlNet NetChecker 5

TRAFFIC

Low Bat

Node On Line

Diagnostic

LMH

Threshold

INPUT

Rockwell

Automation

Push ON

Buzzer

Ext

5VDC

0.25A

Power

Max

Min

0 7

Signal

(x1/4)

GND Trigger

Output to Scope

Node Finder

Power Switch

OFF ON Push ON

Bargraph

Pass/Fail

Slow Edges

Illegal Framing

Poor Signal Quality

Allen-Bradley

Control

NetTM Net

Checker

BNC Connector

SW3

SW2

SW1 (on the side)

Input Jack

Left 1788-CNCHKR ControlNet NetChecker

Rockwell Automation Publication 1788-UM001B-EN-P - August 2012

Right

6 ControlNet NetChecker

Table 1 - NetChecker Specifications

Attribute 1788-CHNHKR

Dimensions 152 x 83 x 33.5 mm (BNC connector not included)

164 x 83 33.5 mm (BNC connector included)

Weight (with batteries) 250 grams (8.18 oz.)

Environmental Operating Temperature: 0…50 °C (32…122 °F)

Slide switch SW1 3-position power switch:

Push switch SW2 Momentar y switch to turn on the instrument when SW1 is in the Push ON position.

Slide switch SW3 4-position function switch:

BNC connector Signal input. Connects to the network trunk cable via a standard tap or the provided cable

Display 8 bi-color (Red/Green) status indicators:

Thumbwheel switches 2-digit decimal switches for entering the address of the Node to find (0 to 99).

DC jack External DC power from AC adapter (nominal 5V DC, max 5.5V @ 0.25A). Jack should have

Oscilloscope connector 3-pin Phoenix connector with Network, Ground, and Trigger signals.

Buzzer Piezo Buzzer provides an audible indication of detected faults.

Batteries 2 alkaline batteries 1.5V AA/LR6 size located in the battery compar tment on the back of the

Battery life 6 hours continuous use Accessor ies • 3-pin plug connector to fit in the oscilloscope output

Agency certification (when product or packaging is so marked)

Storage Temperature: -40…85 °C (-40…185 °F)

• OFF disconnects the batteries.

• ON turns on the tool permanently.

• Push ON provides momentary power.

• Positions L, M, H select the Diagnostic mode and low, medium and high thresholds.

• The rightmost position selects the Bargraph mode.

and BNC T. The NetChecker is electrically isolated from the network by a transformer.

• Status indicators numbered 1 to 7 are dual-function for Diagnostic or Bargraph modes.

• Status indicators named TRAFFIC also indicates a low battery condition.

3.5 mm external diameter (+) and 1.35 mm internal diameter (-).

tool. Batteries are provided uninstalled with the tool. A screwdriver is required to install or replace the batteries.

• BNC T connector

• BNC male to BN C female coaxial cable (1 meter long)

• User Manual 1788 -UM001

• EN 55011, Radi ated Emission Class A

• ENV 50204, Radi ated immunity from digital radio

• IEC 1000-4-2, ESD susceptibility

• IEC 1000-4-3, Ra diated immunity

• IEC 1000-4-4, EFT/B i mmunity

• IEC 1000-4-6, conduc ted RF immunity

Rockwell Automation Publication 1788-UM001B-EN-P - August 2012

ControlNet NetChecker 7

TRAFFIC Status Indicator

This bi-color status indicator at the top of the instrument has two functions:

• Green (network activity)—When the NetChecker is connected to an active network

and powered on this status indicator will turn green to indicate there is activity on the network. Only messages in which a Start Delimiter is detected in the header (and thus are considered valid) can cause this status indicator to turn green.

• Red (low battery)—If the batteries are low the status indicator will turn red, whether or

not the tool is connected to a network.

Modes of Network Analysis

The NetChecker offers two modes of analysis to evaluate a network:

• Diagnostic mode—Provides a global network evaluation. It is selected when slide

switch SW3 is in the L, M, or H position.

• Bargraph mode—Provides a quick view of the signal level on the network, either global

(from all nodes) or from a selected node. It is selected when slide switch SW3 is in its rightmost position.

Diagnostic Mode

In Diagnostic mode positions L, M, and H on slide switch SW3 select one of three fixed voltage references (or thresholds) used by the NetChecker to convert the analog input signal to a binary signal.

Table 2 - Threshold Settings

Sensitivity to Noise SW3 Position Reference Voltage (mV) Volts (peak-to-peak)

Most sensitive L 300 0.6

Moderately sensitive M 450 0.9

Least sen sitive H 600 1 .2

The L (low) reference voltage setting is the most sensitive to input signal or noise. When the L position is selected any input signal exceeding +/-300mV will be converted to a logical “1” and processed by the NetChecker. All input signals between +300mV and -300mV will be converted to a logical “0” and ignored. Note that this sensitivity range is deliberately set above the absolute minimum peak-to-peak voltage required by the ControlNet specification (510mVpp).

The M (medium) and H (high) positions provide higher voltage references and less sensitivity as shown in the table above.

Rockwell Automation Publication 1788-UM001B-EN-P - August 2012

8 ControlNet NetChecker

Status Indicator Functions

When slide switch SW3 is in the Diagnostic (left) area of the front panel, the status indicators have the following functions:

• Pass /Fail status indicator—Indicates the overall quality of the signal on the coaxial

cable. Green when the input signal is clean, this status indicator will turn progressively red if one or more of the criteria of quality are violated.

• Poor Signal Quality status indicator —Blinks red when the message signal is distorted

and/or when the between-messages gap is polluted by noise so that the NetChecker is uncertain if the signal received is a valid message or noise. Distortion and noise are generally the result of reflections of signal on the cable caused by impedance mismatches. The Poor Signal Quality fault detection is dependent on the threshold settings L, M, and H on SW3.

Note that there area number of violations to the Manchester encoding in the ControlNet frame (in Start and End Delimiters). The NetChecker can detect if there are fewer or more violations than expected. In the case of very large distortion of the signal the NetChecker may interpret that there are unexpected violations although the message was generated correctly by the originator node.

• Illegal Framing stat us in dicat or—Blinks red when erratic message detection occurs.

The NetChecker verifies the duration of messages and generates a fault if any message is shorter than 7 bytes (NULL message length). In addition, the time gap between messages must not be less than 6 bytes. These errors are generally caused by high noise level or signal reflection at the end of the messages or during the time gap between messages. These faults are the result of large impedance mismatches on the network. This fault detection is dependent on the threshold settings L, M, and H on SW3.

• Slow Edges status indicator—Blinks red when the NetChecker has identified a weak

signal with poor rise/fall times. This may result from high signal attenuation caused by bad coaxial cable, excessive cable length, or an overloaded network. This fault detection is not dependent on the threshold settings on SW3.

• Node On Line status indicator—Turns green if a node having the address entered in

the Node Finder is detected on the network and the signal received from it is good. The status indicator will turn red or appear yellow (rapidly flashing red and green) if the messages received from this node exhibit one or more of the faults signaled by the fault status indicators.

Rockwell Automation Publication 1788-UM001B-EN-P - August 2012

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