Allen-Bradley 1794 VHSC Very High Speed Counter Module User Manual

Below you will find brief information for Very High Speed Counter Module 1794 VHSC. This module performs high-speed counting for industrial applications. The module is an intelligent I/O module that interfaces signals with any Allen-Bradley programmable controller that has ControlNet capability. Once configured, the 1794 VHSC can operate without flexbus power, but requires customer power for the module, inputs, and outputs. It has two counters that can be configured for 3 encoder modes (X1, X2, X4), counter mode, period/rate mode, continuous/rate mode, rate measurement, and pulse width modulation (PWM). The module also has four outputs that are isolated in pairs and can be tied to any or all counter windows. Each output has a user-selectable on-off value and can be tied back to an input for cascading. The 1794 VHSC provides totalization in period/rate, continuous/rate, and rate measurement modes.

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Allen-Bradley

Very High

Speed Counter

Module

(Cat. No. 1794-VHSC)

User

Manual

--1

Important User Information Because of the variety of uses for the products described in this publication, those responsible for the application and use of this control equipment must satisfy themselves that all necessary steps have been taken to assure that each application and use meets all performance and safety requirements, including any applicable laws, regulations, codes and standards.

The illustrations, charts, sample programs and layout examples shown in this guide are intended solely for example. Since there are many variables and requirements associated with any particular installation,

Allen-Bradley does not assume responsibility or liability (to include intellectual property liability) for actual use based upon the examples shown in this publication.

Allen-Bradley publication SGI--1.1, “Safety Guidelines For The

Application, Installation and Maintenance of Solid State Control”

(available from your local Allen-Bradley office) describes some important differences between solid-state equipment and electromechanical devices which should be taken into consideration when applying products such as those described in this publication.

Reproduction of the contents of this copyrighted publication, in whole or in part, without written permission of Allen--Bradley Company, Inc.

is prohibited.

Throughout this manual we make notes to alert you to possible injury to people or damage to equipment under specific circumstances.

ATTENTION: Identifies information about practices or circumstances that can lead to personal injury or death, property damage, or economic loss.

Attention helps you:

· identify a hazard

· avoid the hazard

· recognize the consequences

Important: Identifies information that is especially important for successful application and understanding of the product.

Important: We recommend you frequently backup your application programs on appropriate storage medium to avoid possible data loss.

FLEX I/O, DeviceNet, DeviceNetManager, and RediSTATION are trademarks of Allen-Bradley Company, Inc.

PLC, PLC--2, PLC--3, and PLC--5 are registered trademarks of Allen-Bradley Company, Inc.

All other brand and product names are trademarks or registered trademarks of their respective companies.

Summary of Changes

This publication contains new and revised information not included in the last release.

New Information

Information has been added to allow you to enhance frequency/resolution on smodules with firmware revision D or later.

Appendix B has been added to illustrate the criteria for CSA hazardous location approval.

Revised Information

Chapter 4 has been revised to include information on using the frequency/resolution feature included in later modules. In addition, the data table image has been revised to include the mode.

Change Bars

The areas in this manual which are different from previous editions are marked with change bars (as shown to the right of this paragraph) to indicate the addition of new or revised information.

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soc--ii Summary of Changes

Publication 1794-UM010B--EN--P -- March 2001

Preface

Using This Manual

Purpose of This Manual

This manual shows you how to use the Very High Speed Counter module with an Allen-Bradley programmable controller. It helps you install, program, and troubleshoot your module.

Audience

You must be able to program and operate an Allen-Bradley programmable controller (PLC) to make efficient use of this module.

We assume that you know how to do this in this manual. If you do not, refer to the appropriate programming and operations manual for the associated programmable controller before you attempt to use this module.

Vocabulary

In this manual, we refer to:

· the Very High Speed Counter module as the “module,” the

“1794-VHSC” or the “VHSC module.”

· the programmable controller as the “controller,” or the “PLC.”

Manual Organization

This manual is divided into 5 chapters. The following chart shows each chapter with its corresponding title and a brief description of the topics covered in that chapter.

Chapter

Title

Overview of the Very High Speed Counter Module

Installing the Very High Speed Counter Module

Topics Covered

Explanation of modes, outputs, and how the module communicates with the processor.

How to install, key, connect wiring, ground and an explanation of the indicators on the module.

Programming Your Very High Speed Counter

Module

Input, Output and Configuration Files for the Very

High Speed Counter on ControlNet

Use RSLogics to program this module.

Identification and description of bit/words for input, output and configuration.

Appendices

Specifications

CSA Hazardous Location Approval

Specifications for the 1794-VHSC module.

Approval criteria for the module.

Publication 1794-UM010B--EN--P -- March 2001

P--2 Using This Manual

Product Compatibility

Related Publications

You can install your input module in any system that uses

Allen-Bradley ControlNet programmable controllers and the 1794

I/O structure.

Contact your nearest Allen-Bradley office for more information about your programmable controllers.

This module can be used with 1794-ACN15 series B and -ACNR15 series B or later ControlNet Adapters. Communication between the module and the processor is bidirectional. The PLC sends module information using ControlNet messages to the adapter. The PLC receives module status information through ControlNet messages from the adapter.

For a list of publications with information on Allen-Bradley programmable controller products, consult our publication index

SD499.

Publication 1794-UM010B--EN--P -- March 2001

Overview of the Very High

Speed Counter Module

How to Install Your Very High

Speed Counter Module

Chapter 1

Chapter Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Module Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Features of the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operation in Encoder or Counter Mode . . . . . . . . . . . . . . . . . . . . .

Counter Mode

Encoder Mode

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preset Value

Rollover Value

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Software Reset

Gate/Reset Input

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operation in

Period/Rate Mode

Continuous/Rate Mode

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operation in Rate Measurement Mode

Pulse Width Modulation

. . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Enabling and Forcing Outputs . . . . . . . . . . . . . . . . . . . . . . . . . .

Assigning Outputs to Counter Windows

Operation of Outputs

. . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

What the Very High Speed Counter Module Does

Chapter Summary

. . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1--8

1--11

1--12

1--13

1--14

1--15

1--16

1--3

1--4

1--6

1--1

1--2

Chapter 2

What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Before You Install Your Input Module

European Union Directive Compliance

. . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . .

EMC Directive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Low Voltage Directive

Power Requirements

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Wiring the Terminal Base Units (1794-TB3G shown)

Installing the Module

. . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mounting the Terminal Base Unit on a DIN Rail

Panel/Wall Mounting

. . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mounting the High Speed Counter Module on the

Terminal Base Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Connecting Wiring for the High Speed Counter Module . . . . . . . . . .

Wiring connections for the 1794-VHSC High Speed

Counter Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2--4

2--6

2--8

2--9

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2--12

Example of Quadrature Encoder Differential Wiring to a 1794-TB3G

Terminal Base Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2--13

Module Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2--14

Chapter Summary 2--15

2--2

2--3

2--4

2--1

Publication 1794-UM010B--EN--P -- March

2001

ii Table of Contents

Programming Your Very High

Speed Counter Module

Input, Output and

Configuration Files for the

Very High Speed Counter on

ControlNet

Troubleshoot the Very High

Speed Counter Module

Specifications

CSA Hazardous Location

Approval

Chapter 3

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3--1

Chapter 4

Chapter Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

About the ControlNet Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Communication Over the FLEX I/O Backplane . . . . . . . . . . . . . . . .

Scheduled Data-Transfer

Unscheduled Data-Transfer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . .

Module I/O Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Application of New Configurations . . . . . . . . . . . . . . . . . . . . . . .

I/O Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Adapter Input Status Word . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Safe State Data

Device Actions

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Communication Fault Behavior . . . . . . . . . . . . . . . . . . . . . . . . .

Idle State Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Input Data Behavior upon Module Removal . . . . . . . . . . . . . . . .

Frequency/Resolution Enhancement . . . . . . . . . . . . . . . . . . . . .

Applying the Frequency/Resolution Enhancement . . . . . . . . . .

High Speed Counter Module (1794-VHSC) Image Table Mapping .

4--1

4--2

4--3

4--4

4--5

4--6

4--7

Chapter 5

What This Chapter Contains

Status Indicators

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diagnostic Codes Returned by the Module . . . . . . . . . . . . . . . . . . .

Diagnostics Reported in Word 8 of the Data Input File

What’s Next

. . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5--1

5--2

5--3

Appendix A

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

24V Input Derating Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A--1

A--3

Appendix B

CSA Hazardous Location Approval . . . . . . . . . . . . . . . . . . . . . . . .

B--1

Publication 1794-UM010B--EN--P -- March 2001

Chapter Objectives

Module Description

Chapter

Overview of the Very High

Speed Counter Module

This chapter gives you information on:

· features of the 1794-VHSC module

· how the module communicates with programmable controllers.

· how the module operates

The VHSC module performs high speed counting for industrial applications. The module is an intelligent I/O module that interfaces signals with any Allen-Bradley programmable controller that has

ControlNet capability.

The VHSC module, once configured for its intended purpose, can continue to operate without flexbus power. (Note: Customer power is required for the module, inputs and outputs.) After scanning the inputs and updating the outputs, the input data is converted to a specified data type in a digital format to be transferred to the processor’s data table on request. Command and configuration data is sent from the programmable controller data tables to the module via ControlNet.

Features of the Module

The HSC module counts pulses from encoders (such as

Allen-Bradley Bulletin 845), pulse generators or mechanical limit switches, proximity switches, etc. and returns either a count or frequency in binary format.

The module’s features include:

· 2 counters configurable for 3 encoder modes, counter mode, period/rate mode, continuous/rate mode, rate measurement and pulse width modulation (PWM)

· 4 outputs, isolated in pairs

· outputs are current-sourcing at 5 or 12-- 24V dc (0.5mA max. @

5V; 1A max. @ 12--24V)

· single-ended or differential inputs

· 2-phase encoder inputs up to a frequency of 250KHz (X 4 mode)

· single-phase counter inputs up to a frequency of 1MHz

· input voltage range of 5 or 24V dc

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1--2 Overview of the Very High Speed Counter Module

· returns input as count or frequency in binary format

· input counts as high as 16,777,215

· up to 1MHz in period/rate or rate measurement frequency modes

· outputs can be tied to any or all counter windows

· each output has a user-selectable on-off value

· outputs can be tied back to an input for cascading

· each counter has a user-selectable preset and rollover value

· totalization is provided in period/rate, continuous/rate and rate measurement modes

· module can continue counting without flexbus power (after configuration)

· outputs have safe state values which can be applied when there is a network failure or the PLC is switched to PROGRAM mode

· pulse width modulation (PWM) mode is available

Operation in Encoder or

Counter Mode

The 1794-VHSC module operates in the following modes:

· counter mode --

· encoder X1 mode

· encoder X2 mode

· encoder X4 mode

· period/rate mode

· continuous/rate mode

· rate measurement frequency mode

· pulse width modulation (PWM)

The operation of the module in these modes is described below.

The operation of encoder and counter modes is virtually identical.

The only difference between the two modes is in the type of feedback used.

Use the counter mode if you need the module to read incoming pulses from a maximum of 2 encoders (single-ended or differential), counters, pulse generators, mechanical limit switches, etc. and return them to the programmable controller as a binary number

(0-16,777,215).

Use the encoder modes if you need the module to read incoming quadrature pulses and return them to the programmable controller as a binary number (0-16,777,215). In these modes, the module accepts two-phase quadrature feedback and counts up or down depending upon the condition of the phase B input for each counter.

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Overview of the Very High Speed Counter Module 1--3

The operation of the module in the encoder/counter modes is as follows:

· counter mode - channel B is direction control (up or down).

Channel A input is used for pulse. The count is bidirectional with the direction determined by channel B.

· encoder X1 - This is a bidirectional count mode; counting up or down, using quadrature input signals.

· encoder X2 - This is a bidirectional count mode, using quadrature input signals, with 2 times the resolution of X1.

· encoder X4 - This is a bidirectional count mode, using quadrature input signals, with 4 times the resolution of X1.

Each of the counters in encoder/counter mode has values associated with it. These are:

· preset value

· rollover value

Counter Mode

The counter mode allows the module to read incoming pulses and return them to the programmable controller processor as a binary number (0-16,777,215).

In the counter mode, direction (up counting or down counting) is determined by the phase B input, which can be a random signal. If

Phase B is high, the counter will count down. If phase B is low or floating, (that is, not connected), the counter counts up.

If Phase B is:

High

Low or floating (not connected)

Counter will count (direction):

Down

The module reads incoming pulses from a maximum of 2 encoders

(single-ended or differential), counters, pulse generators, mechanical limit switches, and so forth and returns a count to the programmable controller processor in a binary number (0-16,777,215).

The counter mode accepts only one phase feedback. This relationship is shown in figure 1.1.

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1--4 Overview of the Very High Speed Counter Module

Figure 1.1

Block Diagram of Counter Mode

Single Phase Pulse Generator

Z (Store Count)

(Gate/Reset)

Count Up

Input A

Input B

Input Z

1794-VHSC

Count Down

A Input

B Input

Count

0 1

3 2

Outputs updated continuously

1 0

Encoder Mode

The encoder mode allows the module to read incoming pulses and return them to the programmable controller processor as a binary number (0-16,777,215).

In this mode, the module will accept two phase quadrature feedback.

The module senses the relationship between the 2 phases and counts up or down accordingly.

Encoder X1 mode -- quadrature input signals count on the leading edge or the trailing edge of channel A for a bidirectional count. The phase relationship between Channel A and Channel B determines direction -- channel A leading, and channel B floating, the count direction is up; channel A lagging, and channel B high, the count direction is down.

Encoder X2 mode -- quadrature input signals count on the leading edge and the trailing edge of channel A for a bidirectional count.

Channel B determines direction -- B low (floating), the count direction is up; B high, the count direction is down.

Encoder X4 mode -- quadrature input signals count on the leading edge and the trailing edge of channel A and channel B for a bidirectional count. Channel B determines direction -- B low

(floating), the count direction is up; B high, the count direction is down.

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Overview of the Very High Speed Counter Module 1--5

Direction of Count

The module can count either up or down, depending upon the condition of the B input for each counter. In encoder applications, the counter will increment on the leading edge of input A, while input B determines the direction of the count.

You also have the option of X1, X2 and X4 multiplying of the input pulses. Figure 1.2 shows the relationships between inputs A and B for forward and reverse directions in encoder applications.

Quadrature Encoder

Forward Rotation

CCW Encoder Rotation

Figure 1.2 Phase Relationship for Forward or Reverse

Directions

High Speed Counter Module

Z (Store Count)

(Gate/Reset)

Input A

Input B

Input Z

1794-VHSC

Reverse Rotation

CW Encoder Rotation

A Input

B Input

Count

1 2 3

1 2 3 4 5 6 7 8 9 10 11 12

Count

1 2 3 4 5 6 7 8 9 10 11 12

Count

2 1 0

12 11 10 9 8 7 6 5 4 3 2 1 0

The following paragraphs apply to both encoders and counters.

10679-I

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1--6 Overview of the Very High Speed Counter Module

Preset Value

Each of the 2 counters has one preset value associated with it. In the encoder or counter modes, the preset value represents a reference point (or count) from which the module begins counting. The module can count either up or down from the preset value. Preset values are loaded into the count registers through the preset count bits. Preset values can range from 0 to 16,777,215 binary.

Rollover Value

Each of the 2 counters has one rollover value associated with it.

When the rollover value is reached by the encoder/counter, it resets to 0 and begins counting again. The rollover values range from 1 to

16,777,216 binary. The rollover value is circular (for example: if you program 360, the count will be from 358, 359, 0, 1 etc. in a positive direction and from 1, 0, 359, 358 etc. in a negative direction).

Software Reset

The counters can also be reset by the Reset Count bits found in Word

0, bits 0 and 4 of the Counter Control word. When one of these bits is set to 1, the associated counter is reset to zero and begins counting.

The module can also be reset with the gate/reset as explained below.

Refer to chapter 4 for further details.

Gate/Reset Input

There is one gate/reset input for each of the 2 counters. The gate/reset input, when active, will function in one of the 4 store count modes outlined below.

Scaling Input Count at the Gate/Reset Terminal

You can scale the incoming count at the gate/reset terminal. Scaling allows the incoming pulses at gate/reset to be divided by a number in the range of 1, 2, 4, 8, 16, 32, 64 and 128.

Store Count

The store count feature allows the module to store the current count value of the associated counter. The store count feature is triggered by the state of the gate/reset terminal on the module. The stored count of each counter is placed in a separate word in the Read Data file. The stored count value will remain in the Read Data file until a new trigger pulse is received at the Gate/Reset terminal. When a new trigger pulse is received, the old count value will be overwritten by the new value.

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Overview of the Very High Speed Counter Module 1--7

In mode 1, store/continue (figure 1.3), the leading edge of a pulse input on input Z (gate/reset) terminal causes the current value in the counter to be read and stored. The counter will continue counting.

The stored count will be available in the Read Data file. The stored count information will remain in the block transfer read file until it is overwritten by new data.

Figure 1.3 Store/Continue

Read, Store Count and continue counting.

10680-I

In mode 2, store/wait/resume (figure 1.4), a rising edge of a pulse input on the Z input (gate/reset) terminal reads and stores the current counter value in the Read Data file, and inhibits counting while the gate/reset input is high. Counting resumes when the input goes low.

Mode 2 does not reset the counter, although it does store the count value. The stored count is available in the Read Data file. The stored count remains in the Read Data file until it is overwritten with new data.

Figure 1.4 Store/Wait/Resume

Store Count

Stop counting

Resume counting

10681-I

In mode 3, store-reset/wait/start (figure 1.5), the rising edge of the pulse on input Z (gate/reset) terminal causes the counter to stop counting, store the current count value in the Read Data file and reset the count to zero. The counter does not count while the Z input on the gate/reset terminal remains high. Counting resumes from zero on the falling edge of the pulse at the Z (gate/reset) terminal. The stored count is available in the Read Data file. The stored count remains in the Read Data file until it is overwritten with new data.

Figure 1.5 Store-Reset/Wait/Start

Counter has stopped counting

Stop count, store and reset to zero

Start counting from zero

10682-I

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1--8 Overview of the Very High Speed Counter Module

In mode 4, store-reset/start (figure 1.6), on the rising edge of a pulse input at the Z (gate/reset) terminal causes the counter to store the accumulated count value in the Read Data file, and reset the counter to zero. The counter continues counting while the Z gate/reset input is high. The stored count is available in the Read

Data file. The stored count remains in the Read Data file until it is overwritten with new data.

Figure 1.6 Store-Reset/Start

Rising Edge Falling Edge

Store Count, reset to zero, start counting.

10683-I

Figures 1.3 through 1.6 show the store count feature operating on the rising edge of the gate/reset pulse. The user has the option of selecting these same features using the falling edge of the gate/reset pulse. The gate invert bit is active in the store count, continuous/rate and period/rate modes.

Operation in

Period/Rate Mode

Use the period/rate mode to determine the frequency of input pulses by counting the number of internal 5MHz clock pulses over a user-specified number of input signal pulses. At the end of the specified number of pulses, the module returns the frequency and the total number of pulses received.

A channel configured for period/rate mode acts as a period rate counter. An internal 5MHz clock is used as a frequency reference.

This clock is gated by the incoming pulse train at the gate/reset input. The results of this gating action are the number of pulses or a frequency. The frequency is returned in input file words 0 (LSW) and 1 (MSW) for channel 0 and word 2 (LSW) and 3 (MSW) for channel 1. The total pulses received is stored in input file words 4

(LSW) and 5 (MSW) for channel 0 and words 6 (LSW) and 7

(MSW) for channel 1. Select the period/rate mode by setting the appropriate bits in word 0 of the configuration block.

1794-VHSC modules count the total number of pulses occurring at the Z (gate/reset) pin. This function is frequency-limited to 200Hz X the scaler value. You can reset this count by setting the VR bit.

Figure 1.7 shows a diagram of the module used in the period/rate mode.

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Overview of the Very High Speed Counter Module

Figure 1.7 Period/Rate Mode

A (not used)

B (not used)

Z (gate/reset)

Single Phase Pulse Generator

Input A

Input B

Input Z scaler

5MHz Clock

1794-VHSC

1--9

Incoming pulse train at Z

(gate/reset terminal)

5MHz internal clock

Accumulated Count

1 10 20

Frequency and Outputs updated here

Assumes symmetrical pulse, 50% duty cycle, so period = sample time on X 2 (on and off)

Frequency = 1/period

If count = 25, scaler = 1, and clock period = (1/5MHz)

Frequency = 1 / [(25/1) X (1/5MHz) X 2] = 100KHz

In Figure 1.7, the incoming pulse train from the gate/reset terminal is used to sample pulses from the 5MHz internal clock. As the frequency of the incoming pulse train at the gate/reset terminal increases, the number of sampled pulses from the 5Mhz clock decreases. This relationship is shown in NO TAG. Since accuracy is related to the number of pulses received over the sample period, the accuracy will decrease with increasing input frequencies at the

Gate/Reset terminal.

To some extent, the decrease in accuracy can be lessened by scaling the input frequency through the use of a scaler. A scaler value of 1 will only return an accurate input frequency if incoming pulses have a 50% duty cycle.

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1--10 Overview of the Very High Speed Counter Module

Table 1.A

Relationship Between Sampled Pulses and Input Frequency

Input Frequency at Z

(Gate/Reset)

Terminal in Hz

1KHz

2KHz

5KHz

10KHz

20KHz

50KHz

100KHz

100

200

500

Sampled Pulses for 1/2 Cycle of Z (Gate/Reset) Pulse

2.5K

1.25K

500

250

125

1.25M

500K

250K

125K

50K

25K

12.5K

Operation of scaler

In period/rate mode, the scaler lets the incoming pulse train at the Z

(gate/reset) terminal be divided by a user defined number.

Acceptable values for the scaler are 1, 2, 4, 8, 16, 32, 64 and 128.

There is one scaler value for each counter.

ATTENTION: Sample period times scaler must be less than 6.71 seconds in order to avoid a zero frequency detect indication.

Connection to Counter Inputs

The only input to the module in the period/rate mode is made to the

Z (gate/reset) terminal. The counter inputs (channel A and B) are not used in the period/rate mode.

Publication 1794-UM010B--EN--P -- March 2001

Overview of the Very High Speed Counter Module 1--11

Continuous/Rate Mode

The continuous/rate mode is similar to the period/rate mode previously described except the outputs in this mode are dynamic outputs. Use this mode to determine the frequency of input pulses by counting the number of internal 5MHz clock pulses over a user-specified number of input signal pulses. Each output is turned on as soon as the turn-on count is reached, and turned off as soon as the turn-off count is reached. As the internal 5MHz clock is counted, the outputs dynamically track the 5MHz count. This allows you to turn an output on a certain number of 5MHz counts after the gate/reset pin goes active, and turn it off a certain number of 5MHz counts later.

1794-VHSC modules count the total number of pulses occurring at the Z (gate/reset) terminal. This function is frequency-limited to

200Hz X the scaler value. This total count is returned in input file words 4 (LSW) and 5 (MSW) for channel 0 and 6 (LSW) and 7

(MSW) for channel 1. You can reset this count by setting the VR bit.

Figure 1.8 Period/Rate and Continuous/Rate Output

Operation with Scaler of 1

A (not used)

Encoder/Pulse Generator

B (not used)

Z (Gate/Reset)

Input A

Input B

Input Z scaler

5MHz Clock

1794-VHSC

Incoming pulse train at Z

(gate/reset terminal)

5MHz internal clock

1 10

Accumulated Count

Outputs updated continuously

Assumes symmetrical pulse, 50% duty cycle, so period = sample time on X 2 (on and off)

Frequency = 1/period

If count = 25, scaler = 1, and clock period = (1/5MHz)

Frequency = 1 / [(25/1) X (1/5MHz) X 2] = 100KHz

Frequency updated here

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1--12 Overview of the Very High Speed Counter Module

Operation in Rate

Measurement Mode

Use the rate measurement mode to count incoming pulses for a user-specified time interval. At the end of the interval, the module returns a value representing the sampled number of pulses and a value indicating the incoming frequency. When the count and frequency are updated, any associated outputs are checked against their associated presets.

The value representing the total number of pulses is returned in input file words 4 (LSW) and 5 (MSW) for channel 0 and 6 (LSW) and 7

(MSW) for channel 1, and the value indicating the incoming frequency is returned in words 0 (LSW) and 1 (MSW) and 2 (LSW) and 3 (MSW). The total count equals the running sum of the number of pulses received during the sample period. The operation of rate measurement mode is shown below in Figure 1.9.

Figure 1.9

Operation of the Rate Measurement Mode

A Input

Encoder/Pulse Generator

B (not used)

Z (not used)

(Gate/Reset)

Input A

Input B

Input Z

Time base

1794-VHSC

A Input (pulse)

Internal Sampling Gate

1 2 3

Accumulated Count

Frequency calculated, outputs updated here

If sample period is 50ms, and count = 3, then frequency = 3/50ms = 60Hz

Example:

In figure 1.9, three counts have been accumulated during the user-selected time period. If you had selected 50 milliseconds as the sample period, the frequency returned to the programmable controller processor would be:

Frequency = Counts/Sample period = 3 counts/50 milliseconds =

60Hz

Publication 1794-UM010B--EN--P -- March 2001

Pulse Width Modulation

Outputs

Overview of the Very High Speed Counter Module 1--13

Sample Period

You can set the sample period used in the frequency calculation in the rate measurement mode. Allowable values are 10 milliseconds to

3 seconds in 10 millisecond increments. The default value is 1 second.

Connection to Counter Inputs

The only user connections used in the rate measurement mode are to phase A of the module. The Z (gate/reset) and channel B terminals are not used in this mode.

The module can generate a pulse width modulation signal that may be tied to any output. By specifying a period (configuration word 2) and gate interval (configuration word 2 or 3) together with the PWM configuration word 2 or 3, a counter and its first ON/OFF window comparator is assigned and the signal generated. The actual duty cycle is specified by output words 2 and 3.

The VHSC module has 4 outputs, isolated in groups of 2. Each of the outputs is capable of sourcing current and will operate between 5 and 24 volts dc. You must connect an external power supply to each of the outputs. The outputs can source 1A dc alone or in combination. The outputs are hardware-driven and will turn on in about 25 ms when the appropriate count value has been reached.

Enabling and Forcing Outputs

Outputs may be forced on or off independent of count or frequency value. To force the outputs, they must first be enabled. Enabling the outputs is done through a data table word 1, bits 1, 5, 9 and 13 (refer to chapter 4). Once the outputs have been enabled, they may be forced on by setting bits 0, 4, 8 or 12 in word 1. The outputs can be forced off by setting the enable bit to 0.

Assigning Outputs to Counter Windows

By setting bits in the configuration block, you can assign the outputs on the module to any of the various counter windows. You can assign any output to any count window with no restrictions.

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1--14 Overview of the Very High Speed Counter Module

Output turns ON at count of 2000.

Operation of Outputs

When the outputs for the VHSC module are enabled and assigned to a counter window they operate in an ON-OFF fashion. For example, assume that the module were programmed to turn ON an output when a count value of 2000 was reached. Further, assume that the user desired to have the output remain energized for a period of 3000 counts and then turn OFF. The end result would be that the outputs would turn ON at count of 2000, would remain energized for 3000 additional counts, and would turn OFF at 5000 counts. The ON and

OFF values are circular around zero. Refer to figure 1.10.

Figure 1.10 On-Off Operation of Output

Output remains energized for 3000 additional counts

Output turns on at count value of 2000

Output turns off at count value of 5000

10686-I

Refer to figure 1.11. Using output 0 as an example, when the value in Counter ON Value is less than the value in Counter OFF Value, the output turns on at 2000 and off at 5000. If the value in Counter

ON Value is greater than the value in Counter OFF Value, the output turns off at 2000 and on at 5000.

Figure 1.11 Effect of Values in On/Off Operation

Output remains energized for 3000 additional counts.

Output turns OFF at count of 5000.

Output turns OFF at count of 2000.

Output turns ON at count of 5000.

When values in Counter ON Value are less than values in Counter OFF Value.

When values in Counter ON Value are greater than values in Counter OFF Value.

10687-I

Isolation of Outputs

The module provides 850V dc isolation between each of the outputs and the flexbus.

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Overview of the Very High Speed Counter Module 1--15

Connecting Outputs to Counters

You can connect any of the outputs to any of the counter inputs. In this way, it is possible to use the outputs to reset a counter or to cascade counters. If using the outputs this way, make certain that the output voltage is compatible with the chosen input.

What the Very High Speed

Counter Module Does

The very high speed counter module performs high-speed scaling calculation operations for various industrial applications. The module interfaces with a FLEX I/O family ControlNet 1794-ACN15 series B or -ACNR15 series B or later adapter which then communicates with a programmable controller processor.

The adapter/power supply transfers data to and from the module over the flexbus. Instructions in the PLC facilitate this communication and let you write output values and configure the module’s mode of operation. The following illustration describes the communication process.

The adapter transfers your configuration data to the module.

External devices transmit frequency signals to the module.

Flexbus

The adapter transfers the data over the flexbus.

Allen-Bradley

VERY HIGH SPEED COUNTER MODULE

1794--VHSC

The adapter and module determine that the transfer was made without error and input values are within a specified range.

The module converts frequency signals into integer format and stores these values until the adapter requests their transfer.

ControlNet transfers the data to the programmable controller data table.

1. The adapter transfers your configuration data and commands to the module.

2. External devices generate input signals that are transmitted to the module.

3. The module converts these signals into binary format, and stores these values and controls their output until the adapter requests their transfer.

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1--16 Overview of the Very High Speed Counter Module

4. The adapter transfers the data over the flexbus.

5. The adapter and module determine that the transfer was made without error and inputs values are within a specified range.

6. ControlNet transfers the data to the PLC data table.

Chapter Summary

In this chapter you learned how your module operates, and how your module communicates with the programmable controller.

Publication 1794-UM010B--EN--P -- March 2001

What This Chapter

Contains

Before You Install Your

Input Module

European Union Directive

Compliance

Chapter

How to Install Your Very High

Speed Counter Module

In this chapter, we tell you:

For information on See page

Before You Install Your Module . . . . . . . . . . . . . . . . . . . . . . . 2--1

European Union Directives . . . . . . . . . . . . . . . . . . . . . . . . . . 2--1

Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2--2

Installing the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2--4 on a DIN rail . . . . . . . . . . . . . . . . . . .

2--4 on a wall/panel on the terminal base

2--6

2--8

Connecting Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2--9

Module Indicators . . . . . . . . . . . . . . . . . .

2--14

Before installing your 1794-VHSC very high speed counter module:

You need to:

Calculate the power requirements of all modules in this FLEX system.

Position the keyswitch on the terminal base

As described under:

Power Requirements, page 2-2

Installing the Module, page 2--4

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

EMC Directive

This product is tested to meet Council Directive 89/336/EEC

Electromagnetic Compatibility (EMC) and the following standards, in whole or in part, documented in a technical construction file:

· EN 50081-2EMC -- Generic Emission Standard, Part 2 --

Industrial Environment

· EN 50082-2EMC -- Generic Immunity Standard, Part 2 --

Industrial Environment

This product is intended for use in an industrial environment.

Publication 1794-UM010B--EN--P -- March

2001

2--2 How to Install Your Very High Speed Counter Module

Low Voltage Directive

This product is tested to meet Council Directive 73/23/EEC

Low Voltage, by applying the safety requirements of EN 61131--2

Programmable Controllers, Part 2 -- Equipment Requirements and

Tests.

For specific information required by EN 61131-2, see the appropriate sections in this publication, as well as the following Allen-Bradley publications:

· Industrial Automation Wiring and Grounding Guidelines For

Noise Immunity, publication 1770-4.1

· Automation Systems Catalog, publication B111

This equipment is classified as open equipment and must be mounted in an enclosure during operation to provide safety protection.

Power Requirements

The wiring of the terminal base unit is determined by the current draw through the terminal base. Make certain that the current draw does not exceed 10A.

ATTENTION: Total current draw through the terminal base unit is limited to 10A. Separate power connections may be necessary.

Publication 1794-UM010B--EN--P -- March 2001

How to Install Your Very High Speed Counter Module

Methods of wiring the terminal base units are shown in the illustration below.

Wiring the Terminal Base Units (1794-TB3G shown)

ATTENTION: Do not daisy chain power or ground from the terminal base unit to any ac or dc digital module terminal base unit.

2--3

Daisy-chaining

Frequency Input

Module

VHSC

Module

VHSC

Module

VHSC

Module

24V dc

Individual

Note: Do not use any digital modules in this configuration.

Wiring when total current draw is less than 10A

Digital Input

Module

VHSC

Module

Digital Input

Module

Digital Output

Module

24V dc

Note: Use this configuration if using any digital output modules that could couple transients to the 24V supply.

VHSC Module wiring separate from digital wiring.

Wiring when total current draw is greater than 10A

Publication 1794-UM010B--EN--P -- March 2001

2--4 How to Install Your Very High Speed Counter Module

Installing the Module

Installation of the very high speed counter module consists of:

· mounting the terminal base unit

· installing the VHSC module into the terminal base unit

· installing the connecting wiring to the terminal base unit

If you are installing your module into a terminal base unit that is already installed, proceed to “Mounting the High Speed Counter

Module on the Terminal Base” on page2--8.

Mounting the Terminal Base Unit on a DIN Rail

ATTENTION: Do not remove or replace a terminal base unit when power is applied. Interruption of the flexbus can result in unintended operation or machine motion.

1. Remove the cover plug (if used) in the male connector of the unit to which you are connecting this terminal base unit.

2. Check to make sure that the 16 pins in the male connector on the adjacent device are straight and in line so that the mating female connector on this terminal base unit will mate correctly.

3. Position the terminal base on the 35 x 7.5mm DIN rail A (A-B pt.

no. 199-DR1).

Position terminal base at a slight angle and hooked over the top of the DIN rail.

4. Make certain that the female flexbus connector C is fully

retracted into the terminal base unit.

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How to Install Your Very High Speed Counter Module 2--5

Slide the terminal base unit over tight against the adapter.

Make sure the hook on the terminal base slides under the edge of the adapter and the flexbus connector is fully retracted.

Press down on the terminal base unit to lock the terminal base on the DIN rail. If the terminal base does not lock into place, use a screwdriver or similar device to open the locking tab, press down on the terminal base until flush with the DIN rail and release the locking tab to lock the base in place.

30077--M

Gently push the flexbus connector into the side of the adapter to complete the backplane connection.

5. Repeat the above steps to install the next terminal base.

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2--6 How to Install Your Very High Speed Counter Module

Panel/Wall Mounting

Installation on a wall or panel consists of:

· laying out the drilling points on the wall or panel

· drilling the pilot holes for the mounting screws

· mounting the adapter mounting plate

· installing the terminal base units and securing them to the wall or panel

If you are installing your module into a terminal base unit that is already installed, proceed to “Mounting the High Speed Counter

Module on the Terminal Base” on page2--8.

Use the mounting kit Cat. No. 1794-NM1 for panel/wall mounting.

1.4

(35.5) 1794-NM1 Mounting Kit

Contents:

1 -- Mounting Plate for Adapter

2 -- 18 #6 self-tapping screws

(2 for the adapter, and 2 each for up to 8 modules)

Adapter Module

(not included)

Terminal Base Unit

(not included)

Publication 1794-UM010B--EN--P -- March 2001

.83 (21)

Inches

(Millimeters)

How to Install Your Very High Speed Counter Module

1.4

(35.5)

To install the mounting plate on a wall or panel:

1. Lay out the required points on the wall/panel as shown in the drilling dimension drawing.

Drilling Dimensions for Panel/Wall Mounting of FLEX I/O

2.3

(58.5)

1.4

(35.5)

2.3

(58.5)

1.4

(35.5)

2--7

More

2. Drill the necessary holes for the #6 self-tapping mounting screws.

3. Mount the mounting plate (1) for the adapter module using two

#6 self-tapping screws (18 included for mounting up to 8 modules and the adapter).

Important: Make certain that the mounting plate is properly grounded to the panel. Refer to “Industrial Automation

Wiring and Grounding Guidelines,” publication

1770-4.1.

4. Hold the adapter (2) at a slight angle and engage the top of the mounting plate in the indention on the rear of the adapter module.

5. Press the adapter down flush with the panel until the locking lever locks.

6. Position the terminal base unit up against the adapter and push the female bus connector into the adapter.

7. Secure to the wall with two #6 self-tapping screws.

8. Repeat for each remaining terminal base unit.

Note: The adapter is capable of addressing eight modules. Do not exceed a maximum of eight terminal base units in your system.

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2--8 How to Install Your Very High Speed Counter Module

Mounting the High Speed Counter Module on the Terminal

Base Unit

The 1794-VHSC module mounts on a 1794-TB3G or TB3GS terminal base unit.

1. Rotate the keyswitch (1) on the terminal base unit (2) clockwise to position 1 as required for this module.

2. Make certain the flexbus connector (3) is pushed all the way to the left to connect with the neighboring terminal base/adapter.

You cannot install the module unless the connector is fully extended.

3. Make sure that the pins on the bottom of the module are straight so they will align properly with the connector in the terminal base unit.

ATTENTION: Remove field-side power before removing or inserting the module. This module is designed so you can remove and insert it under

backplane power. When you remove or insert a module with field-side power applied, an electrical arc may occur. An electrical arc can cause personal injury or property damage by:

· sending an erroneous signal to your system’s field devices causing unintended machine motion

· causing an explosion in a hazardous environment

Repeated electrical arcing causes excessive wear to contacts on both the module and its mating connector.

Worn contacts may create electrical resistance.

Publication 1794-UM010B--EN--P -- March 2001

How to Install Your Very High Speed Counter Module 2--9

4. Position the module (4) with its alignment bar (5) aligned with the groove (6) on the terminal base.

5. Press firmly and evenly to seat the module in the terminal base unit. The module is seated when the latching mechanism (7) is locked into the module.

6. Repeat the above steps to install the next module in its terminal base unit.

Connecting Wiring for the

High Speed Counter

Module

Wiring to the high speed counter module is made through the terminal base unit on which the module mounts.

Compatible terminal base units are:

1794-TB3G

Module

1794-VHSC

1794-TB3G

Yes

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33

A 0 - 15 A

16- 33

34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51

C 34- 51 C

34 and 50 = 24V dc

35 and 51 = common

16 and 33 = chassis ground

40 thru 45 = chassis ground

1794-TB3GS

Yes

1794-TB3GS

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

17 18 19 20 21 22 23

35 36 37 38

24 25 26 27 28 29 30 31 32

39 40 41 42 43 44 45 46 47 48 49 50

Label placed at top of wiring area.

34 and 50 = 24V dc

35 and 51 = common

16 and 33 = chassis ground

40 thru 45 = chassis ground

Connecting Wiring using a 1794-TB3G and -TB3GS Terminal Base

Units

1. Connect the individual signal wiring to numbered terminals on the 0--15 row (A) for +24V inputs (terminals 0--5 and 8--13) and

17--32 row (B) for +5V inputs (terminals 17--22 and 25--30).on

the terminal base unit. Connect the input devices as shown in the wiring table on page 2--12.

ATTENTION: Do not connect 24V signals to the 5V input terminals. Permanent damage to the module will result.

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2--10 How to Install Your Very High Speed Counter Module

2. Connect individual output wiring to terminals 6, 7 and 14, 15 on the 0--15 row (A) and terminals 23, 24 and 31, 32 on the 16--32 row (B) on the terminal base unit. Connect output return wiring for channels 0, 1, 2, and 3 to terminals 23, 24 31 and 32 respectively. Connect the output devices as shown in the wiring table on page 2--12.

3. Terminate any shield to terminals 16 or 33 on row B, or 40 through 45 on row C.

4. Connect +24V dc to terminal 34 on the 34-51 row (C), and 24V common to terminal 35 on the 34-51 row (C).

ATTENTION: To reduce susceptibility to noise, power VHSC modules and digital modules from separate power supplies. Do not exceed a length of 33 ft (10m) for dc power cabling.

5. If daisy chaining the +24V dc power to the next base unit, connect a jumper from terminal 50 (+24V) on this base unit to terminal 34 and from terminal 51 (24V dc common) to terminal

35 on the next base unit.

6. Connect output power wiring to terminals 37 (+) and 39 (--) for outputs 0 and 1, and terminals 46 (+) and 48 (--) for outputs 2 and 3.

ATTENTION: Do not daisy chain power or ground from the VHSC terminal base unit to any ac or dc digital module terminal base unit.

Publication 1794-UM010B--EN--P -- March 2001

How to Install Your Very High Speed Counter Module

0 1 2 3

Connections for Terminal Base 1794-TB3G shown

4 5 6 7 8 9 10 11 12 13 14 15

2--11

A B

24V Inputs

18 19

B Z

20 21

Z O0 O1

22 23 24

A B B Z

24V Inputs

27 28 29

O2 O3

31 32 33

Chassis Gnd

34 35

A B B Z Z R0 R1

5V Inputs

36 37 38 39 40 41 42

A A

B B Z

5V Inputs

45 46 47

Z R2 R3

48 49

Chassis Gnd

50 51

+24V COM

24V dc

Base Power

+V --V

6 Chassis Ground for Shields

Where: A, A -- incremental encoder input A (+5 or +24V dc)

B B -- incremental encoder input B (+5 or +24V dc)

Z, Z -- incremental encoder input Z (+5 or +24V dc)

O = sourcing outputs

R = returns for sourcing outputs

+V = +5 or +24V dc isolated power externally supplied for outputs (1A max.)

--V = negative isolated power connection (1A max.)

+24V dc = 24V dc terminal base power for module

COM = return for +24V dc terminal base power for module

Chassis Gnd = chassis ground for input or output cable shields

--V +24V COM

24V dc

Base Power

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2--12 How to Install Your Very High Speed Counter Module

Wiring connections for the 1794-VHSC High Speed Counter Module

Incremental

Encoder

Input

Input A

Input B

Input Z

Input A

Input B

Input Z

Channel 0

Terminal Base Units

1794- TB3G, - TB3GS

Channel 1

+24V Inputs

Channel 0

+5V Inputs

Channel 1

Outputs

Output

+24V dc base power

+24V dc COM

+5V or +24V

Output Pwr

--V Output Pwr

Chassis GND

Sourcing Out Return

Output Sourcing Out Return

Terminals 34 and 50

Terminals 35 and 51

Terminals 37 and 46

Terminals 39 and 48

Terminals 16, 33, and 40 thru 45

ATTENTION: Total current draw through the terminal base unit is limited to 10A. Separate power connections to the terminal base unit may be necessary.

Publication 1794-UM010B--EN--P -- March 2001

How to Install Your Very High Speed Counter Module

Example of Quadrature Encoder Differential Wiring to a

1794-TB3G Terminal Base Unit

2--13

Z (Store Count)

(Gate/Reset) Quadrature Encoder

(ex. 845H--SJ__24DRY__ )

Mechanical Switch

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

2 3 4 5 6 7 8 9 10 11 12 13 14 15

18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

1794-TB3G

0 - 15

16- 33

34- 51

12V

+ --

Solenoid

Attention: Keep exposed area of inner conductor as short as possible.

24V Base Power

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2--14 How to Install Your Very High Speed Counter Module

Module Indicators

The high speed counter module has one red/green status indicator

(OK) that is on when power is applied to the module and one yellow indicator for each input and output.

Allen-Bradley

VERY HIGH SPEED COUNTER MODULE

1794- VHSC

Indicator

OUT 0, 1, 2, 3

B Z 0

OUT

1 A

B Z

OUT

2 3

C B A

A = Power/status indicator -- indicates power applied to module and status of module.

B = Insertable label for writing individual I/O assignments.

C = Status Indicators --

A = Status of input A

B = Status of input B

Z = Status of gate input Z

OUT = Output indicators, 1 for each output

Indication

Yellow

Off

Yellow

Off

Yellow

Off

Yellow

Off

Explanation

Input A active

Input A not active

Input B active

Input B not active

Input Z active

Input Z not active

Output is on

Individual output is off

Publication 1794-UM010B--EN--P -- March 2001

Chapter Summary

How to Install Your Very High Speed Counter Module 2--15

Indicator

Indication

Red (solid)

Red (flashing)

Green (solid)

Green (flashing)

Explanation

· Hardware diagnostic error, TF set to 1 and module/channel status contains error code.

· Hardware runtime failure (i.e. watchdog timeout), module communication ceases.

· Module is configuring hardware, NR is set to 1.

· Module in test mode (bits 15--8 of counter control word are non--zero), TF set to 1

· Module is active and operating normally.

· Module is not configured.

· Programming error, PE is set to 1 and error code is supplied in bits 11--0 of module/channel status word.

· Field power fault, FP set to 1.

· Adapter powered down, and module local power still active.

· ControlNet cable disconnected.

· PLC in PROG mode.

When an input indicator (yellow) is lighted, it indicates that a valid signal (active high or active low) is present at one of the Input terminals.

In this chapter, we told you how to install your input module in an existing programmable controller system and how to wire to the terminal base units.

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2--16 How to Install Your Very High Speed Counter Module

Publication 1794-UM010B--EN--P -- March 2001

Chapter

Programming Your Very High

Speed Counter Module

To initiate communication between the very high speed counter module and your PLC processor, you must use RSLogix 5 software.

Refer to the RSLogix software manuals for information on communicating with this 1794-VHSC very high speed counter module.

Publication 1794-UM010B--EN--P -- March

2001

3--2 Programming Your Very High Speed Counter Module

Publication 1794-UM010B--EN--P -- March 2001

Chapter

Input, Output and

Configuration Files for the

Very High Speed Counter on

ControlNet

Chapter Objectives

About the ControlNet

Adapter

Communication Over the

FLEX I/O Backplane

Network

ControlNet

Adapter

Read

Write

In this chapter you will learn about:

· ControlNet Adapter

· I/O structure

· safe state data

· communication fault data

· idle state behavior

· input data behavior upon module removal

This module must be used with the FLEX I/O ControlNet adapters

(cat. no. 1794--ACN15 series B and --ACNR15 series B or later) which support extended data transfer (EDT). These adapters interface up to 8 FLEX I/O modules and a ControlNet processor or scanner. The adapter can support ControlNet real--time data connections to individual modules or module groups. Each connection is independent of the others and can be from different processors or scanners.

One 1794-ACN15/B and -ACNR15/B ControlNet adapter can interface up to eight terminal base units with installed FLEX I/O modules, forming a FLEX I/O system of up to eight slots. The adapter communicates to other network system components

(typically one or more controllers or scanners, and/or programming terminals) over the ControlNet network. The adapter communicates with its I/O modules over the backplane.

I/O Module

Inputs

I/O Module

Inputs

I/O Module

Inputs

Status

Read

Words Status Status

Outputs

Configuration

Slot 0

Write

Words

Outputs

Configuration

Slot 1

Outputs

Configuration

Slot 7

Data is exchanged scheduled (when mapped) or unscheduled (using

CIO instructions).

4--2 Input, Output and Configuration Files for the Very High Speed Counter on ControlNet

Scheduled Data-Transfer

Scheduled data transfer:

· is continuous

· is asynchronous to the ladder-logic program scan

· occurs at the actual rate displayed in the Actual Packet Interval field on the programming software ControlNet I/O mapping

(monitor) screen

Unscheduled Data-Transfer

Unscheduled operations include:

· unscheduled non-discrete I/O data transfers—through ControlNet

I/O Transfer (CIO) instructions

· peer-to-peer messaging—through Message (MSG) instructions

· messaging from programming devices

Unscheduled messaging on a ControlNet network is non-deterministic. Your application and your configuration—number of nodes, application program, NUT, amount of scheduled bandwidth used, etc.—determine how much time there is for unscheduled messaging.

Module I/O Mapping

The I/O map for the VHSC module is divided into read words and write words. Read words consist of input and status words, and write words consist of output and configuration words. The number of read words or write words can be 0 or more. The length of each I/O module’s read words and write words vary in size depending on module complexity. Each I/O module will support at least 1 input word or 1 output word. Status and configuration are optional, depending on the module. The VHSC module has 9 input words, no status words, 4 output words and 56 configuration words.

Application of New Configurations

When a configuration is sent to the 1794--VHSC module, it is checked for consistency before being applied. If an error is found in the configuration, the PE bit (input word 8, bit 15) is asserted and the module locally retains its previous configuration. To isolate any problems an improperly configured module may have, the user application program (i.e. ladder program) should monitor this error.

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I/O Structure

Input, Output and Configuration Files for the Very High Speed Counter on ControlNet 4--3

If the configuration is considered acceptable, the counter application specific integrated circuit (ASIC) is disabled (i.e. counting is suspended and outputs are shut off), while the ASIC is loaded with the new operational parameters.

Output data is received by the adapter in the order of the installed

I/O modules. The Output data for Slot 0 is received first, followed by the Output data for Slot 1, and so on up to slot 7.

Network WRITE

The first word of input data sent by the adapter is the Adapter Status

Word. This is followed by the input data from each slot, in the order of the installed I/O modules. The Input data from Slot 0 is first after the status word, followed by Input data from Slot 2, and so on up to slot 7.

Network READ

ControlNet Adapter

Read Data

Adapter Status

Slot 0 Input Data

... ...

Slot 7 Input Data

Output Data

Slot 0 Output Data

Slot 1 Output Data

Read

Write

I/O Module

Slot 0

I/O Module

Slot 1

...

I/O Module

Slot 7

Slot 7 Output Data

Adapter Input Status Word

Bit:

The input status word consists of:

· I/O module fault bits -- 1 status bit for each slot

· node address changed -- 1 bit (created by PLC--5 controller)

· I/O status -- 1 bit (created by PLC--5 controller)

15 10 through 15 9 8 7 6

I/O Module Fault Bits

5 4 3 2 1 0

Not Used

Created by PLC--5 controller I/O State Bit

Node Address Changed Bit

The adapter input status word bit descriptions are shown in the following table.

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4--4 Input, Output and Configuration Files for the Very High Speed Counter on ControlNet

Bit Description

Node Address Changed

(Created by PLC--5 controller.)

I/O State (Created by

PLC--5 controller.)

Bit

Explanation

This bit is set (1) when an error is detected in slot position 0.

This bit is set (1) when an error is detected in slot position 1.

This bit is set (1) when an error is detected in slot position 2.

This bit is set (1) when an error is detected in slot position 3.

This bit is set (1) when an error is detected in slot position 4.

This bit is set (1) when an error is detected in slot position 5.

This bit is set (1) when an error is detected in slot position 6.

This bit is set (1) when an error is detected in slot position 7.

This bit is set (1) when the node address switch setting has been changed since power up.

Bit = 0 -- idle

Bit = 1 -- run

10 thru 15 Not used -- set to 0.

Safe State Data

Device Actions

Possible causes for an I/O Module Fault are:

· transmission errors on the FLEX I/O backplane

· a failed module

· a module removed from its terminal base

· incorrect module inserted in a slot position

· the slot is empty

· the slot contains a non--discrete module

The ControlNet adapter does not provide storage for alternate module output data during communication faults or processor idle state. This “safe state data” is stored in the VHSC module and may be defined using configuration software. Safe state data assures that a known output will be applied to the output devices to maintain a previously designated safe operating condition during the previously mentioned failure modes. This data is sent in the configuration block

(see Image Table Mapping later in this chapter).

Device actions include:

· communication fault behavior

· idle state behavior

· input data behavior upon module removal

Publication 1794-UM010B--EN--P -- March 2001

Input, Output and Configuration Files for the Very High Speed Counter on ControlNet

Communication Fault Behavior

You can configure the VHSC response to a communication fault.

Upon detection of a communication fault, the module can:

· leave the module output data in its last state (hold last state)

· reset the module output data to zero (reset)

· apply safe state data to the module output

4--5

Idle State Behavior

The VHSC module responds to idle state (PLC in PROGRAM mode) according to the Communication Fault Behavior described above. The module can:

· leave the module output data in its last state (hold last state)

· reset the module output data to zero (reset)

· apply safe state data to the module output

Input Data Behavior upon Module Removal

I/O module input data sent by the adapter upon module removal is configurable. The adapter can:

· reset the module output data to zero (reset)

· leave the module output data in the last state before module removal (hold last state)

Frequency/Resolution Enhancement

This mode is only for use in modules with firmware revision D or later.

The upper byte of the counter control word (output word 0) is reserved for special modes. Only mode 8, Enhancing

Frequency/Resolution is available. In this mode, you can change significant digits of frequency display based on output word 3 for channel 0 and output word 4 for channel 1. Decimal point placement is absolute positioning. (--2 moves decimal point left 2 places dividing the frequency value by 100; +1 moves the decimal point 1 place, multiplying by 10, and so on). This allows frequency values to fit in a single word.

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4--6 Input, Output and Configuration Files for the Very High Speed Counter on ControlNet

Applying the Frequency/Resolution Enhancement

To use this mode, proceed as follows

ATTENTION: Use this enhancement mode with caution since no checks are performed to verify data.

Unintended operation can occur.

1. Power up the FLEX chassis, or put the PLC into RUN mode, or both. Let the 1794--VHSC module initialize as normal. Wait for the ’OK’ indicator on the module to go solid green.

2. You must place ladder logic in your PLC that performs the following:.

A. Set a value between --4 and +2 into output word 2 and/or 3.

B. Then set (1) the M11 bit in the upper byte of control word 0.

When the upper byte of the output word is not zero, the status indicator flashes red, and the TF bit (bit 12, input word 8) is asserted.

C. Next, reset (0) the M11 bit in the upper byte of output control word 0.

Clearing the upper byte of output word 0 restores the module to an operational state, clears the TF bit in input word 8. and returns the indicator to green. The module is now in inhanced mode.

3. To turn this feature off:

A. Set output word 2 or 3 to zero (no value)

B. Set (1) the M11 bit

C. Then reset (0) the M11 bit

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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet 4--7

ControlNet Files

Input File Size

1 to 9 Words

Output File Size

0 to 4 Word

Configuration File Size

56 Words

High Speed Counter Module (1794-VHSC) Image Table Mapping

Module Image

Channel 0 Current Count (least significant word)

Channel 0 Current Count (most significant word)

Channel 1 Current Count (least significant word)

Channel 1 Current Count (most significant word)

Channel 0 Stored/Accumulated Count (least significant word)

Channel 0 Stored/Accumulated Count (most significant word)

Channel 1 Stored/Accumulated Count (least significant word)

Channel 1 Stored/Accumulated Count (most significant word)

PE FP NR TF OS OS OS OS C1 C0 ZF ZS C1 C0 ZF ZS

Reserved

0 LC OE FO

M11 Reserved 0 VR CP CR

0 LC OE FO 0 LC OE FO

Channel 0 PWM Output Value (0- 95.00%)

Channel 1 PWM Output Value (0- 95.00%)

0 VR CP CR

0 LC OE FO

Counter Configuration

Filter Selection

Time Base Value/PWM Period

Channel 0 Gate Interval

Channel 1 Gate Interval

Reserved

Channel 0 Rollover Value (least significant word)

Channel 0 Rollover Value (most significant word)

Channel 1 Rollover Value (least significant word)

Channel 1 Rollover Value (most significant word)

Channel 0 Preset Value (least significant word)

Channel 0 Preset Value (most significant word)

Channel 1 Preset Value (least significant word)

Channel 1 Preset Value (most significant word)

Channel 0 Scaler

Channel 1 Scaler

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4--8 Input, Output and Configuration Files for the Very High Speed Counter on ControlNet

Configuration File Size

56 Words

0 0

S4 S3 S2 S1 F4 F3 F2 F1

First Counter 1st On Value (least significant word)

First Counter 1st On Value (most significant word)

First Counter 1st Off Value (least significant word)

First Counter 1st Off Value (most significant word)

First Counter 2nd On Value (least significant word)

First Counter 2nd On Value (most significant word)

First Counter 2nd Off Value (least significant word)

First Counter 2nd Off Value (most significant word)

First Counter 3rd On Value (least significant word)

First Counter 3rd On Value (most significant word)

First Counter 3rd Off Value (least significant word)

First Counter 3rd Off Value (most significant word)

First Counter 4th On Value (least significant word)

First Counter 4th On Value (most significant word)

First Counter 4th Off Value (least significant word)

First Counter 4th Off Value (most significant word)

First Counter 3rd On Value

(least significant word)

Second Counter 1st On Value (most significant word)

Second Counter 1st Off Value (least significant word)

Second Counter 1st Off Value (most significant word)

Second Counter 2nd On Value (least significant word)

Second Counter 2nd On Value (most significant word)

Second Counter 2nd Off Value (least significant word)

Second Counter 2nd Off Value (most significant word)

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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet

Configuration File Size

(continued)

56 Words

Second Counter 3rd On Value

Second Counter 3rd Off Value (least significant word)

Second Counter 3rd Off Value (most significant word)

Second Counter 4th On Value (least significant word)

Second Counter 4th On Value (most significant word)

Second Counter 4th On Value (least significant word)

Second Counter 4th Off Value (most significant word)

Counter Control Safe State

Output Control Safe State

Channel 0 PWM Safe State

Channel 1 PWM Safe State

(least significant word)

(most significant word)

4--9

Input Word

Word 0

Word 1

Word 2

Word 3

Word 4

Word 5

Bit

00--15

(00--17)

00--15

(00--17)

00--15

(00--17)

00--15

(00--17)

00--15

(00--17)

00--15

(00--17)

Definition

Channel 0 current count The current count consists of 2 words (32 bits) representing the current count of the 24--bit counter (in encoder, X2 encoder,

/ / measurement.). The range of values is (0 < value < 16,777,215).

Channel 1 current count The current count consists of 2 words (32 bits) representing the current count of the 24--bit counter (in encoder, X2 encoder,

X4 encoder, PWM) or the frequency (in period/rate, continuous/rate, rate measurement.). The range of values is (0 < value < 16,777,215).

Channel 0 stored/accumulated count These are 32--bit long word values representing the stored count of the counter at the time of some specified event.

These words are not updated in counter modes (counter, X1 encoder, X2 encoder, X4 encoder) without store modes selected. With store modes selected, it is the counter value at the time of the specified Z input event.

In PWM configuration, it is the counter value at the end of the period specified by the product of the time base times gate interval.

y g

In period/rate and continuous/rate, it is the total accumulation of unscaled Z pulses (i.e. if scaling is set to 128, the accumulator will increase by 128 counts). The maximum frequency that accumulation can follow is (200Hz X

Scaler value).

In rate measurement, it is the total number of pulses seen at the A input accumulated over each period as specified by the product of time base times gate interval. The range of values occupy the entire 32--bit size from 0 < value

< 4,294,967,295. These words are not cleared by changing the configuration.

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4--10 Input, Output and Configuration Files for the Very High Speed Counter on ControlNet

Input Word

Word 6

Word 7

Bit

00--15

(00--17)

00--15

(00--17)

02, 03

Definition

Channel 1 stored/accumulated count These are 32--bit long word values representing the stored count of the counter at the time of some specified event.

These words are not updated in counter modes (counter, X1 encoder, X2 encoder, X4 encoder) without store modes selected.With store modes selected, it is the counter value at the time of the specified Z input event.

In PWM configuration, it is the counter value at the end of the period specified by the product of the time base times gate interval.

y g

Scaler value).

< 4,294,967,295. These words are not cleared by changing the configuration.

Module Channel Status Word

Zero input status bit (ZS) for Channel 0This bit represents the present status of the Z input.

0 = Off

1 = Input on

This bit is uneffected by Z invert, ZI, in the counter configuration word.

Zero frequency detected bit (ZF) for Channel 0 Only used during frequency configurations (period/rate, continuous/rate, and rate measurement). In period/rate and continuous/rate, counts are acquired during on state of the Z input. At very low frequencies, the counter saturates, indicating a zero frequency detect. The time it takes to determine a zero frequency in these 2 configurations can be as long as 6.7s (16,777,215 counts

X 1/5MHz X 2 half cycles of Z). In rate measurement, pulses on Z are counted over a sample interval specified by the product of time base X gate interval.

The time to detect a zero frequency is determined by the sample interval

(example: time base = 0.100s, gate interval = 3 is 300ms to determine ZF).

Stored/data count bit (C0, C1) for Channel 0 This count cycles thru 00, 01,

10, 11, 00... Each time the stored/accumulated count words are updated,

C(0,1) is incremented. The PLC sample rate, including network delay and program scan, must be as fast or faster than the frequency of the event which updates.

Zero input status bit (ZS) for Channel 1 This bit represents the present status of the Z input.

0 = Off

1 = Input on

Zero frequency detected bit (ZF) for Channel 1 Only used during frequency configurations (period/rate, continuous/rate, and rate measurement). In period/rate and continuous/rate, counts are acquired during on state of the Z input. At very low frequencies, the counter saturates, indicating a zero frequency detect. The time it takes to determine a zero frequency in these 2 configurations can be as long as 6.7s (16,777,215 counts

X 1/5MHz X 2 half cycles of Z). In rate measurement, pulses on Z are counted over a sample interval specified by the product of time base X gate interval.

The time to detect a zero frequency is determined by the sample interval

(example: time base = 0.100s, gate interval = 3 is 300ms to determine ZF).

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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet 4--11

Input Word

Word 8 continued

Bit

06, 07

08--11

(10--13)

12 (14)

13 (15)

14 (16)

15 (17)

Definition

Stored/data count bit (C0, C1) for Channel 1 This count cycles thru 00, 01,

10, 11, 00... Each time the stored/accumulated count words are updated,

C(0,1) is incremented. The PLC sample rate, including network delay and program scan, must be as fast or faster than the frequency of the event which updates.

Output status indicators (OS) Bit 08 corresponds to output 0, bit 09 to output 1, bit 10 to output 2, and bit 11 to output 3.

0 = output Off

1 = output On

Test/fail bit (TF) If the flexbus power or terminal base power is applied and the module fails during hardware tests, a fatal error occurs. The TF bit is asserted and the red module indicator turns on. An error code will be set in the module/channel status word which can be read using a CIO instruction. The

TF bit is also asserted if the upper byte of the counter control word is not zero.

The upper byte of the counter control word is reserved for special modes. Only mode 8, Enhancing Frequency/Resolution is available. To use this mode, set bit 11, and set a value in output woed 3 and/or 4. When the upper byte of word

12 is not zero, the red module status indicator will flash and the TF bit is asserted to indicate the module has entered a test--mode state. Clearing the upper byte of output word 0 restores the module to an operation state, clears the TF bit and returns the indicator to green.

0x08 This test mode is only for use in modules with firmware revision D or later.

Change significant digits of frequency display based on word

14 for channel 0 and word 15 for channel 1 (--2 moves decimal point left 2 places dividing the frequency value by 100; +1 moves the decimal point 1 place, multiplying by 10, and so on).

This allows frequency values to fit in a single word.

CAUTION: Use this test mode with caution since no check is performed to assure that the returned frequency is meaningful.

Firmware revision D changed decimal point placement to absolute positioning. Revision D firmware also checks for placement to be in the range of --4 to +2. A value outside the range moves the decimal point to the zero position. Moving the decimal point to the left allows high frequencies, (commonly present in rate measurement) to fit within a single word. Moving the decimal point to the right allows low frequencies (commonly present in period and continuous rate modes) to have resolution displayed to 0.1Hz and 0.01Hz. Do not use scalars of Z/128, Z/64, Z/32 and Z/16 when using this test mode.

Not ready status bit (NR) Whenever 24V dc power is applied to the module, the hardware must be initialized. The NR bit will be asserted and the red module indicator will flash. If the red indicator continues flashing, and the green indicator momentarily turns on, the 24V dc power is below the module minimum.

Field power fault bit (FP) If the 24V dc module power drops, the FP bit is asserted, the green module indicator flashes, the module outputs turn off, and the module enters an idle state reporting status as it waits for power to be restored. Note: this bit does not indicate status of either output customer power supply.

Programming error bit (PE) This bit is asserted if incomplete, incorrect or conflicting set of configuration parameters are sent to the module. The green module status indicator will flash and an error code will be placed in bits 11:0 of the module/channel status word. The module will not enter a normal operating state. Bit definitions are shown in Chapter 5.

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4--12 Input, Output and Configuration Files for the Very High Speed Counter on ControlNet

Output Word

Word 0

08--10

(10--12)

11 (13)

Bit

00--15

(00--17)

12--15

(14--17)

Definition

Counter Control Word

Channel 0 Counter reset bit (CR) A 0 to 1 transition of this bit clears the counter. Outputs are adjusted according to the window compare values.

Channel 0 Counter preset bit (CP) A 0 to 1 transition of this bit sets the counter to the value specified by the preset words. Outputs are adjusted according to the window compare values.

Channel 0 Value reset bit (VR) A 0 to 1 transition of this bit clears the stored/accumulated count words.

This bit is always 0.

Channel 1 Counter reset bit (CR) A 0 to 1 transition of this bit clears the counter. Outputs are adjusted according to the window compare values.

Channel 1 Counter preset bit (CP) A 0 to 1 transition of this bit sets the counter to the value specified by the preset words. Outputs are adjusted according to the window compare values.

Channel 1 Value reset bit (VR) A 0 to 1 transition of this bit clears the stored/accumulated count words.

This bit is always 0.

Reserved for factory use.

Frequency/Resolution enhancement bit (M11) Refer to input word 8.

Set this bit to 1 for enhancement. Note that you must place a value between

--4 and +2 in output word 3 and/or 4.

Reserved for factory use.

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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet 4--13

Output Word

Word 1

Bit

00--15

(00--17)

Definition

Output Control Word

Output 0 Force output bit (FO) When set to 1, output is turned on if OE is

1. When FO = 0, output can be controlled by a compare match or as directed by the PWM settings.

Output 0 Output enable bit (OE) When set to 1, output can be turned on from a force on, compare match or as directed by the PWM settings. When

OE = 0, the associated output is turned off.

Output 0 Local control bit (LC) When set to 1, output is controlled the counter if the flexbus power is lost. (i.e. the module detects a flexbus reset signal). (Note: When flexbus power is lost, communication to the PC is lost.)

When LC = 0, the module clears its OE bit at a loss of flexbus power. Set this bit as appropriate in the safe state word, since a communication fault occurs after adapter power is lost.

Not used -- set to 0.

Output 1 Force output bit (FO) When set to 1, output is turned on if OE is

1. When FO = 0, output can be controlled by a compare match or as directed by the PWM settings.

Output 1 Output enable bit (OE) When set to 1, output can be turned on from a force on, compare match or as directed by the PWM settings. When

OE = 0, the associated output is turned off.

Output 1 Local control bit (LC) When set to 1, output is controlled the counter if the flexbus power is lost. (i.e. the module detects a flexbus reset signal). (Note: When flexbus power is lost, communication to the PC is lost.)

When LC = 0, the module clears its OE bit at a loss of flexbus power. Set this bit as appropriate in the safe state word, since a communication fault occurs after adapter power is lost.

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4--14 Input, Output and Configuration Files for the Very High Speed Counter on ControlNet

Output Word

Word 1 continued

Word 2

Word 3

Bit

08 (10)

09 (11)

10 (12)

11 (13)

12 (14)

13 (15)

14 (16)

15 (17)

00--15

(00--17)

00--15

(00--17)

Definition

Not used -- set to 0.

Output 2 Force output bit (FO) When set to 1, output is turned on if OE is

1. When FO = 0, output can be controlled by a compare match or as directed by the PWM settings.

Output 2 Output enable bit (OE) When set to 1, output can be turned on from a force on, compare match or as directed by the PWM settings. When

OE = 0, the associated output is turned off.

Output 2 Local control bit (LC) When set to 1, output is controlled the counter if the flexbus power is lost. (i.e. the module detects a flexbus reset signal). (Note: When flexbus power is lost, communication to the PC is lost.)

When LC = 0, the module clears its OE bit at a loss of flexbus power. Set this bit as appropriate in the safe state word, since a communication fault occurs after adapter power is lost.

Not used -- set to 0.

Output 3 Force output bit (FO) When set to 1, output is turned on if OE is

1. When FO = 0, output can be controlled by a compare match or as directed by the PWM settings.

Output 3 Output enable bit (OE) When set to 1, output can be turned on from a force on, compare match or as directed by the PWM settings. When

OE = 0, the associated output is turned off.

Output 3 Local control bit (LC) When set to 1, output is controlled the counter if the flexbus power is lost. (i.e. the module detects a flexbus reset signal). (Note: When flexbus power is lost, communication to the PC is lost.)

When LC = 0, the module clears its OE bit at a loss of flexbus power. Set this bit as appropriate in the safe state word, since a communication fault occurs after adapter power is lost.

Not used -- set to 0.

Channel 0 PWM Output value When the module is configured for PWM, the time base is enabled, the counter for the respective channel, its gate interval, rollover and 1st on and 1st off value are used. Ties can be used to direct the PWM signal to any or all outputs. The range of the PWM values is

0 < value < 9500 decimal (i.e. 0.00% < value < 95.00%). The actual duty cycle at the output depends on the turn on and turn off times of the

MOSFET, energy storage capability of the cable/load and the resistance from output to return.

Channel 1 PWM Output value When the module is configured for PWM, the time base is enabled, the counter for the respective channel, its gate interval, rollover and 1st on and 1st off value are used. Ties can be used to direct the PWM signal to any or all outputs. The range of the PWM values is

0 < value < 9500 decimal (i.e. 0.00% < value < 95.00%). The actual duty cycle at the output depends on the turn on and turn off times of the

MOSFET, energy storage capability of the cable/load and the resistance from output to return.

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Input, Output and Configuration Files for the Very High Speed Counter on ControlNet 4--15

Configuration

Word

Configuration

Word 0

Bit

Bits 00--03

Bits 08--11

(10--13)

Bits 04--07

Bits 12--14

(14--16)

Bit 15 (17)

Definition

(16)

Counter Configuration The upper byte of this word configures counter 1, the lower byte counter 0.

03 02 01 00 Counter 0

(13)

(12)

(11)

(10) Counter 1

0 Counter

Mode Selection

Encoder

Encoder X2

PWM

0 Encoder X4

1 Period/Rate

0 Continuous/Rate

Rate Measurement

05 04 Counter 0

(15)

(14) Counter 1

0 Store count disabled

1 Mode 1 -- store/continue

Mode 2 -- store/wait/resume

Mode 3 -- store;reset/wait/start

Mode 4 -- store;reset/start

Invert the Z signal -- 0 = Z not inverted; 1 = Z inverted

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4--16 Input, Output and Configuration Files for the Very High Speed Counter on ControlNet

Configuration

Word

Word 1

Word 2

Word 3

Word 4

Word 5

Word 6 and 7

Word 8 and 9

Word 10 and

Word 12 and

Bit Definition

Bits 00- 03

Filter Selection - Only 1 filter selection can be chosen at a time. Frequency = 50% duty cycle.

03 02 01 00 Counter 0

Bits 08- 11

(10- 13)

(13)

(12)

(11)

(10) Counter 1

0 No filter

1 50kHz (10ms + 0ms/--1.6ms)

0 5kHz (100ms + 0ms/--13.2ms)

0 500Hz (1.0ms + 0ms/--1.25ms)

0 50Hz (10.0ms + 0ms/--1.25ms)

Bit 12 (14) Input A filter bit (AF) -- 0 = not filtered; 1 = apply filter to input

Bit 13 (15) Input B filter bit (BF) -- 0 = not filtered; 1 = apply filter to input

Bit 14 (16) Input Z filter bit (ZF -- 0 = not filtered; 1 = apply filter to input

Bit 15 (17) Set to 0.

Bits 00--15

(00-17)

Bits 00--15

(00-17)

Bits 00--15

(00-17)

Time base Sets the fundamental time base for both counters. Resolution in ms, with a minimum of 10ms intervals (10ms = 10; 1s = 1000). Time base must be entered when

PWM and rate measurement are configured. The maximum programmed value is

3000.

Channel 0 Gate interval Sets the individual counter gate interval using the time base setting as its time unit. Actual gate interval is time base X gate interval (i.e. time base of 10

X gate interval of 5 = 50ms). Maximum value is 3s. Gate interval must be entered when

PWM and rate measurement are configured.

Channel 1 Gate interval Sets the individual counter gate interval using the time base setting as its time unit. Actual gate interval is time base X gate interval (i.e. time base of 10

X gate interval of 5 = 50ms). Maximum value is 3s. Gate interval must be entered when

PWM and rate measurement are configured.

Bits 00--15

(00-17)

Do not use -- reserved.

Bits 00--15

(00-17)

Bits 00--15

(00-17)

Bits 00--15

(00-17)

Bits 00--15

(00-17)

Channel 0 Rollover Sets the number of counts the counter accumulates before rolling over. For example, a setting of 1000 produces a count sequence of 998, 999, 0, 1, 2... while incrementing; and 2, 1, 0, 999, 998... while decrementing. Rollover is a 32--bit number with a usable range of 16,777,216. In PWM, this value is zero; in count, X1 encoder, X2 encoder and X4 encoder configurations, it must be some specified nonzero number. The value doesn’t matter in period/rate, continuous/rate and rate measurement configurations.

Channel 1 Rollover Sets the number of counts the counter accumulates before rolling over. For example, a setting of 1000 produces a count sequence of 998, 999, 0, 1, 2... while incrementing; and 2, 1, 0, 999, 998... while decrementing. Rollover is a 32--bit number with a usable range of 16,777,216. In PWM, this value is zero; in count, X1 encoder, X2 encoder and X4 encoder configurations, it must be some specified nonzero number. The value doesn’t matter in period/rate, continuous/rate and rate measurement configurations.

Channel 0 Preset This word sets the preset value the counter is loaded with when CP is asserted. This number has a range of 0 < value < 16,777,216.

Channel 1 Preset This word sets the preset value the counter is loaded with when CP is asserted. This number has a range of 0 < value < 16,777,216.

Publication 1794-UM010B--EN--P -- March 2001

Input, Output and Configuration Files for the Very High Speed Counter on ControlNet 4--17

Configuration

Word

Words 16 to 19

Bit

Bits 00--15

(00-17)

Bits 00--15

(00-17)

Bits 00

Bits 08--15

(10--17)

Definition

Channel 0 Scaler This word scales the Z signal in period/rate and continuous/rate modes . If the filter is applied, the filtered Z signal is scaled. Set only 1 bit of the Scaler.

Selecting a Scaler causes accumulated counts to be adjusted accordingly (i.e. selecting a

Scaler of 128 increases the accumulated count by 128 after 128 Z pulses have been received). We recommend using the filter to reduce erroneous frequency readings any time you use the Scaler on the Z input.

Z Fmins (frequency at which the 24-bit counter overflows) = 0.149Hz

Z/2 Fmins (frequency at which the 24-bit counter overflows) = 0.298Hz

Z/4 Fmins (frequency at which the 24-bit counter overflows) = 0.596Hz

Z/8 Fmins (frequency at which the 24-bit counter overflows) = 1.192Hz

Z/16 Fmins (frequency at which the 24-bit counter overflows) = 2.384Hz

Z/32 Fmins (frequency at which the 24-bit counter overflows) = 4.768Hz

Z/64 Fmins (frequency at which the 24-bit counter overflows) = 9.537Hz

Z/128 Fmins (frequency at which the 24-bit counter overflows) = 19.073Hz

Channel 1 Scaler This word scales the Z signal in period/rate and continuous/rate modes . If the filter is applied, the filtered Z signal is scaled. Set only 1 bit of the Scaler.