Allen-Bradley 1756-CFM User manual

ControlLogix Configurable
Flowmeter Module
Catalog Number 1756-CFM
User Manual Original Instructions

Rockwell Automation Publication 1756-UM010C-EN-P - June 2021
Important User Information
Read this document and the documents listed in the additional resources section about installation, configuration, and
operation of this equipment before you install, configure, operate, or maintain this product. Users are required to familiarize
themselves with installation and wiring instructions in addition to requirements of all applicable codes, laws, and standards.
Activities including installation, adjustments, putting into service, use, assembly, disassembly, and maintenance are required to
be carried out by suitably trained personnel in accordance with applicable code of practice.
If this equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be
impaired.
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.
Labels may also be on or inside the equipment to provide specific precautions.
WARNING: 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.
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 consequence.
IMPORTANT Identifies information that is critical for successful application and understanding of the product.
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.
ARC FLASH HAZARD: Labels may be on or inside the equipment, for example, a motor control center, to alert people to potential Arc
Flash. Arc Flash will cause severe injury or death. Wear proper Personal Protective Equipment (PPE). Follow ALL Regulatory
requirements for safe work practices and for Personal Protective Equipment (PPE).

Rockwell Automation Publication 1756-UM010C-EN-P - June 2021 3
Table of Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Who Should Use This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Summary of Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Additional Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 1
What is the Configurable
Flowmeter Module?
What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Using a ControlLogix CFM Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Module Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Physical Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Typical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Understanding Module Input Capabilities. . . . . . . . . . . . . . . . . . . . . . . . . 12
Understanding Module Output Capabilities . . . . . . . . . . . . . . . . . . . . . . . 12
Using Module Identification and Status Information. . . . . . . . . . . . . . . 13
Chapter 2
Configurable Flowmeter
Operation in the
ControlLogix System
What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Ownership . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Using RSNetWorx and the Programming Software . . . . . . . . . . . . . . . . 17
CFM Modules in Local Chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
CFM Modules in Remote Chassis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Direct Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Listen-Only Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Configurable Flowmeter Modules in a Local Chassis. . . . . . . . . . . . . . . . 19
Requested Packet Interval (RPI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Configurable Flowmeter Modules in a Remote Chassis . . . . . . . . . . . . . 20
Chapter 3
Configurable Flowmeter Module
Features and Operational Modes
What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Understanding General Module Features. . . . . . . . . . . . . . . . . . . . . . . . . . 21
Removal and Insertion Under Power (RIUP) . . . . . . . . . . . . . . . . . . . 21
Module Fault Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Fully Software Configurable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Electronic Keying. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Producer/Consumer Model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Module Status Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Configurable Flowmetering Channels . . . . . . . . . . . . . . . . . . . . . . . . . 29
Flowmeter Inputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Gate Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
User-Defined Preset and Rollover Values. . . . . . . . . . . . . . . . . . . . . . . 30

4Rockwell Automation Publication 1756-UM010C-EN-P - June 2021
Current-Sourcing Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Choosing an Operational Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Operating in High Resolution Frequency Mode . . . . . . . . . . . . . . . . . . . . 31
Terminal Usage in High Resolution Frequency Mode . . . . . . . . . . . 32
Output Operation in High Resolution Frequency Mode . . . . . . . . . 32
Module Features Used in High Resolution Frequency Mode . . . . . 32
Alarms in High Resolution Frequency Mode. . . . . . . . . . . . . . . . . . . . 34
Sample Configuration for High Resolution Frequency Mode. . . . . 34
Operating in Totalizer Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Nonresettable Totalizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Terminal Usage in Totalizer Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Output Operation in Totalizer Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Using the Totalizer Mode Prover Function. . . . . . . . . . . . . . . . . . . . . . . . . 36
Using a Prover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Features Available with the Prover Function. . . . . . . . . . . . . . . . . . . . 38
Alarms with the Prover Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Sample Configuration for Totalizer Mode Prover Function . . . . . . 43
Using the Totalizer Mode Filler Function . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Trickle Function for Totalizer Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Configurable Features Available with the
Totalizer Mode Filler Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Alarms with the Filler Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Sample Configuration for Totalizer Mode Filler Function. . . . . . . . 51
Configurable Output Behaviors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
How To Enable Output Behavior Configuration . . . . . . . . . . . . . . . . 53
Chapter 4
Install the Configurable
Flowmeter Module
What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Installing the Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Keying the Removable Terminal Block/Interface Module . . . . . . . . . . . 58
Key the Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Key the RTB/IFM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Wiring the Removable Terminal Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Connect Grounded End of the Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Connect Ungrounded End of the Cable . . . . . . . . . . . . . . . . . . . . . . . . 60
Connect Wires to the RTBs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Wiring the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Standard Flowmeter Wiring Example . . . . . . . . . . . . . . . . . . . . . . . . . 61
Standard Prover/Detector Wiring Example 1 . . . . . . . . . . . . . . . . . . . 62
Standard Prover/Detector Wiring Example 2. . . . . . . . . . . . . . . . . . . 63
Standard Output Wiring Example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Assembling the Removable Terminal Block and Housing . . . . . . . . . . . 65
Installing the Removable Terminal Block on the Module . . . . . . . . . . . . 65
Removing the Removable Terminal Block from the Module . . . . . . . . . 66
Removing the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Rockwell Automation Publication 1756-UM010C-EN-P - June 2021 5
Chapter 5
Configure the Configurable
Flowmeter Module
What This Chapter Contains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Using This Chapter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Overview of the Configuration Process. . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Creating a New Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Communication Format. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Electronic Keying. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Using the Default Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Altering the Default Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Accessing the Tags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Changing Configuration Information at the Tags . . . . . . . . . . . . . . . . . . 78
Configurable Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Downloading Configuration Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Changing Configuration During CFM Module Operation . . . . . . . . . . . 80
Using Ladder Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Using Message Instructions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Processing Real-Time Control and Module Services . . . . . . . . . . . . . 81
One Service Performed Per Instruction . . . . . . . . . . . . . . . . . . . . . . . . 81
Creating a New Tag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Enter Message Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
Configuring CFM Modules in a Remote Chassis. . . . . . . . . . . . . . . . . . . . 86
Sample Configuration for High Resolution Frequency Mode . . . . . . . . 88
Sample Configuration for Totalizer Mode Prover Function. . . . . . . . . . 91
Sample Configuration for Totalizer Mode Filler Function . . . . . . . . . . . 96
Digital Filter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Appendix A
Troubleshooting the
Configurable Flowmeter Module
What This Appendix Contains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Using the Status Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Using Programming Software to Troubleshoot Your Module . . . . . . . 104
Determining Fault Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Using Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Appendix B
Software Configuration Tags Configuration Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Input Tags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Output Tags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

6Rockwell Automation Publication 1756-UM010C-EN-P - June 2021
Appendix C
Module Schematics What This Appendix Contains. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Input Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Flowmeter Inputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Gate Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Output Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Discrete Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Appendix D
Frequency Accuracy Frequency Accuracy in High Resolution Frequency Mode . . . . . . . . . . 125
Calculate Frequency Accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Frequency Accuracy in Totalizer Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Calculate Frequency Accuracy. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Appendix E
Configure Output Behavior with
RSLogix 5000 Version 16 and
Earlier
Configure the 1756-CFM for Use in a New Application . . . . . . . . . . . . . 130
Add the 1756-Generic Profile to the Program. . . . . . . . . . . . . . . . . . . 130
Copy and Paste the Tags and Logic from the Example to Your
Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
Specify the Configurable On/Off Behavior . . . . . . . . . . . . . . . . . . . . 133
Configure a 1756-CFM Module for Use in an Existing Application. . . 134
Add the 1756-Generic Profile to the Program. . . . . . . . . . . . . . . . . . . 134
Copy and Paste the Tags and Logic from the Example to Your
Program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Specify the Configurable On/Off Behavior . . . . . . . . . . . . . . . . . . . . 137
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

Rockwell Automation Publication 1756-UM010C-EN-P - June 2021 7
Preface
This manual describes how to install, configure, and troubleshoot your
ControlLogix® Configurable Flowmeter (CFM) module, catalog number 1756-
CFM, herein referred to as the module.
Who Should Use This Manual You must be able to program and operate an Allen-Bradley®ControlLogix
controller to efficiently use your configurable flowmeter module.
Summary of Changes This table contains the changes made to this revision of the publication.
Additional Resources These documents contain additional information concerning related products
from Rockwell Automation.
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.
Topic Page
Updated Gross Rate formulas 42 and 49
Updated Net Rate formula 50
Added another Standard Prover/Detector wiring example 63
Digital Filter 101
Added Series B status indicators 103
Rising edge resets count. See Table 16 115
Added Series B module gate input schematic information 121
Added Series B module discrete output schematic information 123
Resource Description
1756 ControlLogix I/O Technical Data, publication
1756-TD002 Provides specifications for the ControlLogix controllers, I/O modules, specialty modules, chassis, power supplies and accessories.
ControlLogix System User Manual, publication
1756-UM001 Detailed description of how to use your ControlLogix operating
system.
ControlLogix Digital I/O Modules User Manual,
publication1756-UM058 Detailed description of how to install and use ControlLogix digital I/O
modules.
ControlLogix Analog I/O Modules User Manual,
publication 1756-UM009 Detailed description of how to install and use ControlLogix analog I/O modules.
ControlLogix High-speed Counter Module
Installation Instructions, publication 1756-IN018 Detailed description of how to install and use the ControlLogix high-
speed counter module.
Industrial Automation Wiring and Grounding
Guidelines, publication 1770-4.1 Provides general guidelines for installing a Rockwell Automation
industrial system.
Product Certifications website, http://
www.ab.com Provides declarations of conformity, certificates, and other certification details.

8Rockwell Automation Publication 1756-UM010C-EN-P - June 2021
Notes:

Rockwell Automation Publication 1756-UM010C-EN-P - June 2021 9
Chapter 1
What is the Configurable Flowmeter Module?
What This Chapter Contains This chapter describes the ControlLogix® configurable flowmeter module.
It also describes what you must know and do before using the module.
The ControlLogix CFM module is an intelligent I/O module that performs
high-speed flowmetering for industrial applications. The module is a single-
slot module that interfaces between a Logix controller and external I/O
devices.
The module interfaces with these output types:
• Magnetic Pickup
• TTL
•Preamps
Using a ControlLogix
CFM Module
ControlLogix CFM modules mount in a ControlLogix chassis and use a
removable terminal block (RTB) or a Bulletin 1492 interface module cable that
connects to an IFM to connect all field-side wiring.
Before you install and use your module you should have already:
• installed and grounded a 1756 chassis and power supply.
To install these products, refer to these publications:
-ControlLogix Power Supply, publication 1756-IN619
- ControlLogix Redundant Power Supply, publication 1756-IN620
-ControlLogix Chassis, publication 1756-IN621
• ordered and received an RTB or IFM and its components for your
application.
IMPORTANT RTBs and IFMs are not included with your module.

10 Rockwell Automation Publication 1756-UM010C-EN-P - June 2021
Chapter 1 What is the Configurable Flowmeter Module?
Module Features
These features available on the 1756-CFM module allow greater system
applicability:
• Two configurable flowmetering channels
• Flowmeter inputs
•Gateinputs
• Two current-sourcing outputs
• Removal and insertion under power
•CEmarked
•ULlisted
• CSA certified for Class I Division 2 hazardous locations
For a complete listing and detailed explanation of all the features available on
the ControlLogix CFM module, see Configurable Flowmeter Module Features
and Operational Modes on page 21.
Physical Features
•ControlLogix backplane connector - The backplane connector interface
for the ControlLogix system connects the module to the ControlLogix
backplane.
•Connectors pins - Input/output, power and grounding connections are
made to the module through these pins with the use of an RTB or IFM.
•Locking tab - The locking tab anchors the RTB or IFM cable on the
module, maintaining wiring connections.
•Slots for keying - Mechanically keys the RTB to prevent inadvertently
making the wrong wire connections to your module.
Indicators Locking Tab
Removable Terminal Block
Slots for
Keying the
RTB
Connector Pins
Top and
Bottom
Guides
ControlLogix Backplane
Connector
METERING
DC I/O
O
K
F
0
Z
0
F
1
Z
1
O
0
O
1

Rockwell Automation Publication 1756-UM010C-EN-P - June 2021 11
Chapter 1 What is the Configurable Flowmeter Module?
•Status indicators - Indicators display the status of communication,
module health and input/output devices. Use these indicators to help in
troubleshooting.
•Top and bottom guides - Guides provide assistance in seating the RTB or
IFM cable onto the module.
Typical Applications
You can use the module in power management, automotive, food and
beverage, and oil and gas industries for various flow and/or turbine metering
applications.
This figure shows a module in a turbine shaft speed-monitoring application.
In this example, the module is operating in High Resolution Frequency mode.
Other examples are shown in Chapter 3 to reflect the various operational
modes available on the module.
For a detailed explanation of how the module works with other portions of a
ControlLogix control system, see Chapter 2, Configurable Flowmeter
Operation in the ControlLogix System.
42731
CV
Pulse Output
Fuel
Monitors Fuel Flow
and Total Gallons
Generator
Electricity
Shaft
Encoder
Turbine
Shaft Speed
1756-CFM
Logix Controller
The controller
monitors shaft
speed, performs PID
calculations and
adjusts valve by a
1756-OF8I analog
output module.
1756-OF8I

12 Rockwell Automation Publication 1756-UM010C-EN-P - June 2021
Chapter 1 What is the Configurable Flowmeter Module?
Understanding Module Input
Capabilities
The module accepts input for up to two channels (mode dependent). Each of
the input channels can connect to:
• Magnetic Pickup - 50mV trigger
• TTL output - 1.3V trigger
• Preamp outputs - 4V trigger
You configure the module’s two input channels for your specific application(s).
Each input channel has two input selections:
• Flowmeter Input (F0 & F1) - Connect input device to this input.
• Gate Input (Z0 & Z1) - Accepts 4-40V DC input pulses from open
collectors or external contact closures. These inputs are used in Totalizer
mode to interface to a prover when a prover is enabled.
Understanding Module
Output Capabilities
The module has two assignable outputs. These outputs are designed for
applications that require fast response. The outputs:
• are electrically fused/current limited to 4 amps; the total output
combination is limited to 7 amps.
• can be assigned to any input channel with user-defined trigger
parameter (see Table 1).
• are current sourcing at 10-31.2V DC (1 amp maximum per output).
• must be connected to an external power supply.
• can be forced ON or OFF by the program.
IMPORTANT You can assign both outputs to a given channel; however, you
cannot use the same output with two different channels.
Table 1 - Assign the 1756-CFM Module Outputs
In this operational mode You can assign outputs that are configured to
trigger
Totalizer Frequency (acceleration) Prover status
Fill control
High Resolution Frequency Frequency
Frequency rate of change (acceleration)

Rockwell Automation Publication 1756-UM010C-EN-P - June 2021 13
Chapter 1 What is the Configurable Flowmeter Module?
Using Module Identification
and Status Information
Each ControlLogix CFM module maintains specific identification information
that separates it from all other modules. This information assists you in
tracking all the components of your system.
For example, you can track module identification information to be aware of
exactly what modules are in any ControlLogix rack at any time. While
retrieving module identity, you can also retrieve the module’s status.
Each module maintains the information in Table 2:
Table 2 - Module Identification and Status Information
Module Identification Description
Product Type Module product type, such as Digital I/O or
Analog I/O module
Catalog Code Module catalog number
Major Revision Module major revision number
Minor Revision Module minor revision number
Status
Module status. Returns this information:
• Controller ownership (if any)
• Whether module has been configured
• Device Specific Status, such as:
-Self-Test
- Flash update in progress
- Communications fault
- Not owned (outputs in Program mode)
- Internal fault (need flash update)
-Runmode
- Program mode (output mods only)
• Minor recoverable fault
• Minor unrecoverable fault
• Major recoverable fault
• Major unrecoverable fault
Vendor ID Module manufacturer vendor, for example, Allen-Bradley
Serial Number Module serial number
Length of ASCII Text String Number of characters in module text string
ASCII Text String Number of characters in module text string
IMPORTANT You must perform a WHO service to retrieve this information.

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Chapter 1 What is the Configurable Flowmeter Module?
Notes:

Rockwell Automation Publication 1756-UM010C-EN-P - June 2021 15
Chapter 2
Configurable Flowmeter Operation in
the ControlLogix System
What This Chapter Contains This chapter describes how the module works within the ControlLogix®
system.
In traditional industrial applications, controllers poll flowmeter modules to
obtain their status. Controllers also send commands to the flowmeter
modules. Retrieving flowmeter status and sending commands occurs during
the normal I/O program scan.
ControlLogix CFM modules do not follow the traditional operational manner.
Instead, they use the Producer/Consumer Model (see page 29 for more
information) to produce data without having been polled by a controller first.
Configurable flowmeter modules follow these basic operational steps, as
shown in Figure 1.
1. The Logix controller establishes a connection to the module and
downloads configuration via ladder logic and message instructions.
2. Flowmeters transmit input signals to the module.
3. The module calculates volume from accumulated pulse counts as
engineering units.
4. Rather than being scanned by an owner-controller, the module
periodically multicasts its status to the controller. (see Requested Packet
Interval (RPI) on page 19.) The module also multicasts its status to
controllers connected by a listen-only connection (page 18).

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Chapter 2 Configurable Flowmeter Operation in the ControlLogix System
5. The Logix owner-controller processes the data it received from the
module and returns the appropriate data.
Figure 1 - 1756-CFM Basic Operational Steps
Ownership Every 1756-CFM module in the ControlLogix system must be owned by a
Logix5550®controller. The owner-controller:
• stores configuration data for every module that it owns.
• can be local or remote in regard to the I/O module’s position.
• sends configuration data to the module to define the module’s behavior
within the control system.
Each module continuously maintains communication with its owner during
normal operation. When connections are severed or compromised, the module
performs as configured, either setting all outputs to reset (ON or OFF) or
continuous operations.
Other controllers can also listen to the module (while another controller owns
the module) through a listen-only connection. For more information on listen-
only connections, see page 18.
IMPORTANT The module communication or multicasting behavior varies depending
upon whether it operates in the local chassis or in a remote chassis. The
following sections detail the differences in data transfers between these
setups.
Input
Device
1
2
4
5 3
1756-CFMLogix Controller

Rockwell Automation Publication 1756-UM010C-EN-P - June 2021 17
Chapter 2 Configurable Flowmeter Operation in the ControlLogix System
Using RSNetWorx and the
Programming Software
The I/O configuration portion of the programming software generates
configuration data structures and tags for that module, whether the module is
in a local or remote chassis. A remote chassis, also known as networked,
contains the module but not the module’s owner-controller.
After creating the module, you can write specific configuration in the module’s
data structures; you must access the module tags to change information in the
data structures. This process is explained in detail in Chapter 5, Configure the
Configurable Flowmeter Module.
CFM Modules in Local Chassis
Configurable flowmeter modules in the same chassis as the owner-controller
are ready to run as soon as the configuration data has been downloaded.
CFM Modules in Remote Chassis
You must run RSNetWorx™ software to enable modules in the networked
chassis. Running RSNetWorx software transfers configuration data to
networked modules and establishes a network update time (NUT) for
ControlNet®. The NUT is compliant with the desired communications options
specified for each module during configuration.
Follow these general guidelines when configuring modules:
1. Configure all 1756-CFM modules for a given controller by using
programming software and download that information to the controller.
2. If the configuration data references a module in a remote chassis, run
RSNetWorx software.
IMPORTANT Application-specific configuration data is transferred to the controller
during the program download and sent to the module during the initial
powerup. After module operation has begun, you must use ladder logic
and message instructions to make configuration changes.
IMPORTANT RSNetWorx software must be run whenever a new module is added to a
networked chassis. When a module is permanently removed from a
remote chassis, we recommend that RSNetWorx software be run to
optimize the allocation of network bandwidth.

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Chapter 2 Configurable Flowmeter Operation in the ControlLogix System
Connections Logix controllers make connections to 1756-CFM modules to exchange data.
The controller can make either of these connections to a module:
•Direct Connections - Only one controller can make this connection to a
module.
•Listen-Only Connections - Multiple controllers can make this connection
to a module simultaneously.
Direct Connections
A direct connection is a real-time data transfer link between the controller and
the device that occupies the slot that the configuration data references. When
module configuration data is downloaded to an owner-controller, the
controller attempts to establish a direct connection to each of the modules
referenced by the data. One of these events occurs:
• If the data is appropriate to the module found in the slot, a connection is
made and operation begins.
• If the configuration data is not appropriate, the data is rejected and an
error message displays in the software. In this case, the configuration
data can be inappropriate for any of a number of reasons. For example, a
module’s configuration data can be appropriate except for a mismatch in
electronic keying that prevents normal operation.
The controller maintains and monitors its connection with a module. Any
break in the connection, such as removal of the module from the chassis while
under power, causes the controller to set fault status bits in the data area
associated with the module. The programming software can monitor this data
area to announce the modules’ failures.
Listen-Only Connections
Any controller in the system can listen to the data from any 1756-CFM module
even if the controller does not own the module (in other words, it does not have
to hold the module’s configuration data to listen to the module).
During the module creation process in the programming software, you can
specify the ‘Listen-Only’ Communication Format. For more information on
Communication Format, see page 74.
Choosing ‘Listen-Only’ mode allows the controller and module to establish
communications without the controller sending any configuration data. In
this instance, another controller owns the module.
IMPORTANT Each 1756-CFM module requires one connection.
IMPORTANT Controllers using the Listen-Only mode continue to receive data multicast
from the module as long as a connection between an owner and module
is maintained.
If the connection between all owners and the module is broken, the
module stops multicasting data and connections to all ‘Listening
controllers’ are also broken.

Rockwell Automation Publication 1756-UM010C-EN-P - June 2021 19
Chapter 2 Configurable Flowmeter Operation in the ControlLogix System
Configurable Flowmeter
Modules in a Local Chassis
CFM modules multicast their data periodically. Multicast frequency depends
on the options chosen during configuration and where in the control system
the module physically resides. The data consumer (an owner-controller) is
responsible for knowing that the format of the new data is integers.
Requested Packet Interval (RPI)
This configurable parameter instructs the module to multicast its channel and
status data to the local chassis backplane at specific time intervals.
The RPI instructs the module to multicast the current contents of its on-board
memory when the RPI expires, (that is, the module does not update its
channels prior to the multicast) as shown in this figure.
IMPORTANT You set the RPI value during the initial module configuration and can
adjust it when the controller is in Program mode.
The minimum RPI is determined by channel usage. For each channel
using High Resolution Frequency mode, add 5 ms to the minimum RPI.
For each channel using Totalizer mode, add 50 ms to the minimum RPI.
For example, if one channel uses High Resolution Frequency mode and
the other goes unused, the minimum RPI = 5 ms. If one channel uses High
Resolution Frequency mode and the other uses Totalizer mode, the
minimum RPI = 55 ms.
On-Board Memory
Status Data
Flowmeter 0
Flowmeter 1
Ch 0
Ch 1

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Chapter 2 Configurable Flowmeter Operation in the ControlLogix System
Configurable Flowmeter
Modules in a Remote Chassis
If a module resides in a networked chassis, the role of the RPI changes slightly
with respect to getting data to the owner.
The RPI not only defines when the module multicasts data within its own
chassis (as described in the previous section), but also determines how often
the owner-controller will receive it over the network.
When an RPI value is specified for a module in a remote chassis, in addition to
instructing the module to multicast data within its own chassis, the RPI also
“reserves” a spot in the stream of data flowing across the ControlNet network.
The timing of this “reserved” spot may or may not coincide with the exact value
of the RPI, but the control system guarantees that the owner controller
receives data at least as often as the specified RPI.
See Figure 2 for a better understanding of the data flow with a module in a
remote chassis.
Figure 2 - Module in Remote Chassis with RPI Reserving a Spot in Flow of Data
ControlNet
CFM data at least as often as RPI
Data in remote chassis
at the RPI rates
Owner controller ControlNet Bridge module ControlNet Bridge module CFM module