Hardy HI 1756-nDF User Manual

HI 1756-1DF and HI 1756-2DF

Corporate Headquarters

9440 Carroll Park Drive, Suite 150 San Diego, CA 92121 Phone: 1-800- 821-5831 FAX: (858) 278-6700 Web-site: http://www.hardysolutions.com

Dispenser Filler Control Module

User’s Guide

Hardy Process Solutions Document Number: 0596-0322-01 Revision B

Local Field Service

Hardy has over 200 field technicians in the U.S., and more positioned throughout the world to assist you in your support needs. We also have factory engineers who will travel to your facility anywhere in the world to help you solve challenging applications. We're ready to support you with:

Installation and start-up Routine maintenance and certification Plant audits and performance measurement Emergency troubleshooting and repair

To request Emergency Service and Troubleshooting, Start-up, Installation, Calibration, Verification or to discuss a Maintenance Agreement please call 800-821-5831 (Standard Hours 6:30 AM to 5:00 PM Pacific Standard Time).

Outside the U.S

Hardy Process Solutions has built a network of support throughout the globe. For specific field service options available in your area please contact your local sales agent or our U.S. factory at +1 858-292-2710.

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Contents

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CONTENTS ........................................................................................................... I

CHAPTER 1 OVERVIEW ..................................................................................... 1

About Hardy Manuals ................................................................................................................................. 1

HI 1756 nDF Overview ................................................................................................................................. 1

Typical Applications ................................................................................................................................... 2

Features and Capabilities ............................................................................................................................. 2

CHAPTER 2 SPECIFICATIONS .......................................................................... 5

Basic Specifications ....................................................................................................................................... 5

General ........................................................................................................................................................ 5

Environmental Requirements ...................................................................................................................... 6

Pending Approvals ...................................................................................................................................... 6

CHAPTER 3 INSTALLATION .............................................................................. 7

Unpacking ...................................................................................................................................................... 7

Installing the HI 1756 nDF ........................................................................................................................... 7

Allen-Bradley ControlLogix Processor or Remote Rack ............................................................................ 7

A ControlLogix Chassis .............................................................................................................................. 7

Removing the Module from the Chassis ..................................................................................................... 8

Installing the Module I/O Connector ........................................................................................................... 8

Load Cell Wiring Diagrams ......................................................................................................................... 9

HI 1756 1DF Valve wiring diagram ............................................................................................................. 9

Hardy HI 215IT Junction Box ................................................................................................................... 10

CHAPTER 4 CONFIGURATION ........................................................................ 11

Power Check ................................................................................................................................................ 11

LEDs ......................................................................................................................................................... 11

Dot Matrix Display .................................................................................................................................... 12

Setting Up Communications ....................................................................................................................... 12

Configuring the HI 1756-nDF Dispenser Filler Module in the RSLogix 5000 for ControlLogix with the

HI 1756-nDF Module Add on Profile ....................................................................................................... 12

Linking the PLC with the HI 1756-nDF Dispenser Filler Control Module ............................................... 15

Overview of Operation ................................................................................................................................ 16

DINT Configuration Parameters used in Flow Rate Control .................................................................... 18

REAL Configuration Parameters used in Flow Rate Control .................................................................... 19

DINT Configuration Parameters used in Auto-Preact ............................................................................... 22

REAL Configuration Parameters used in Auto-Preact .............................................................................. 22

Status Values used in Auto-Preact function .............................................................................................. 23

Assembly Object Instances ......................................................................................................................... 25

First Word – 0: Command Number .......................................................................................................... 27

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Contents

Command Return or Error Codes .............................................................................................................. 29

Second and Third Words - 1, 2: Parameter Number and Value ............................................................. 29

DINT Configuration Parameters ............................................................................................................... 29

REAL Configuration Parameters .............................................................................................................. 34

REAL Status Values .................................................................................................................................. 38

Integrated Technician ................................................................................................................................ 40

CIP Messages ............................................................................................................................................ 41

CHAPTER 5 CALIBRATION .............................................................................. 43

Pre-Calibration Procedures ........................................................................................................................ 43

Electrical Check Procedures ...................................................................................................................... 43

Load Cell/Point Input/Output Measurements ............................................................................................ 43

Load Check ............................................................................................................................................... 44

AOP Calibration .......................................................................................................................................... 44

C2 Calibration ............................................................................................................................................. 44

“THE BUTTON” C2 Calibration .............................................................................................................. 45

C2 Calibration Using Ladder Logic .......................................................................................................... 45

Hard Calibration ......................................................................................................................................... 46

Hard Calibration Ladder Logic Example .................................................................................................. 46

CHAPTER 6 TROUBLESHOOTING ............................................................... 47

Disassembly and Reassembly Notes, Warnings and Cautions ................................................................ 47

Weight and Voltage Testing ....................................................................................................................... 47

IT Test ....................................................................................................................................................... 48

General Troubleshooting Flow Chart Index ............................................................................................. 48

A1 - Guidelines for Instabilities on Formerly Operating System .............................................................. 49

B - Guidelines for Instabilities on Formerly Operating Systems (Cont’d) ................................................ 50

B1 - Guidelines for Instabilities on Formerly Operating Systems (Cont’d) .............................................. 51

B1 - Guidelines for Instabilities on Formerly Operating Systems (Cont’d) .............................................. 52

Testing an individual load cell signal output requires an IT Summing Junction box or millivolt meter. .. 53

Use the load cell certificate to verify the millivolt per volt (mV/V) rating: .............................................. 53

G - Calibration Failed ................................................................................................................................ 54

H - Mechanical Inspection ........................................................................................................................ 55

J - Electrical Inspection ............................................................................................................................. 56

K - Load Sharing and Load Sensor Checkout ........................................................................................... 57

Erratic Flow Rates ...................................................................................................................................... 58

System and Load Cell Tests ........................................................................................................................ 58

INTEGRATED TECHNICIAN (IT®) ...................................................................................................... 59

Stability Test ............................................................................................................................................. 60

Weight and Voltage Test ........................................................................................................................... 60

General Policies and Information .............................................................................................................. 60

Warranty .................................................................................................................................................... 61

For Further Information Contact ............................................................................................................... 61

INDEX ................................................................................................................ 62

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Chapter 1

Chapter 1 Overview

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This manual provides users and service personnel with specifications and procedures for installing, configuring, operating, maintaining, and troubleshooting the Hardy Process Solutions HI 1756 nDF Dispenser Filler with WAVERSAVER®, C2®, and INTEGRATED TECHNICIANTM (IT®) diagnostics.

NOTE WAVERSAVER, C2, and IT are registered trademarks of Hardy Process Solutions, Inc.

To ensure good performance and maximum service life, follow all guidelines described in this manual. Be sure you understand all cautions, warnings, and safety procedures. If you find that the information in this manual does not provide the help you need, contact the HI Customer Service Department at:

Phone: (858) 278-2900 FAX: (858) 278-6700 Web Site: www.hardysolutions.com Support e-mail address: support@hardysolutions.com

About Hardy Manuals

An overview of each chapter’s contents is listed below:

Chapter One - Provides an overview of HI 1756 nDF capabilities and features Chapter Two - Provides a overview of HI 1756 nDF specifications Chapter Three - Describes the steps for installing both the standard and optional HI

1756 nDF equipment, and the HI 215IT series junction box

Chapter Four - Explains how to configure the HI 1756 nDF Chapter Five - Provides calibration instructions Chapter Six – Provides troubleshooting procedures for repair of the HI 1756 nDF

HI 1756 nDF Overview

The HI 1756 nDF is a ControlLogix I/O module, which is designed to operate in a local rack or a remote rack that is connected to the local chassis via a network link.

The module can be inserted and removed under power without disruption of any other modules in the system (racks). This makes it possible to replace a failed module while keeping the rest of the system running. Status indicators will be provided on the front of the module for fault status. A status block will provide information to the processor for alarming and troubleshooting (IT).

The HI 1756 nDF can be purchased as a single channel (1756 1DF) or dual channel (1756 2DF) module; enabling up to two separate single or multi-cell weight scales to be monitored at one time. Two relays are assigned to each weigh scale input, and can be triggered by programmable target weight and preact weight values.

The analog-to-digital converter in the weigh module controller is capable of 8,388,608 counts of resolution which allows the instrument to tolerate large “dead” loads, over sizing of load cells/sensors, and still have sufficient resolution to provide accurate weight measurement and control. The analog-to-digital converter can be configured to provide either 95 or 145 updates per second. The 95 updates per second mode is recommended

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Chapter 1

for nosier environments while the 145 updates per second mode provides a faster response time to changes in the flow rate.

The module supports both C2 electronic calibration and hard calibration (i.e., traditional calibration with weights).

Typical Applications

Dispenser filler control can be used in a variety of material-flow applications. The 1756 nDF Controller can control up to two ingredients per weigh scale channel, in a

filler mode, using two integrated DC or AC relays which can be independently controlled automatically through programmable set point values or manually. The setpoint values can be adjusted throughout the fill cycle, however once a relay is OPENED (external valve is closed) it cannot be CLOSED again until the next fill cycle is started.

Features and Capabilities

C2® Calibration

Traditional calibration uses certified test weights. C2® Electronic Calibration allows a scale to be calibrated without the need for test weights. A C2® weighing system consists of up to eight load cell sensors per channel, a junction box, interconnect cable, and an instrument with C2® capabilities (e.g., the HI 1756 nDF). Each Hardy Process Solutions C2-certified load sensor outputs digital information used for calculating the calibration. When the HI 1756 nDF reads the signals from the load sensors, it calibrates the scale based on the load sensor’s output plus a user-supplied reference point value (from 0 to any known weight on the scale).

NOTE C2® is registered trademarks of Hardy Process Solutions Inc.

WAVERSAVER®

When measuring small weight changes, the affects of mechanical vibration and noise from the feeders and plant environment can introduce substantial interference. WAVERSAVER factors out vibration, noise, and other interference-related signals from the load cell so the rate controller can better decipher the actual weight data.

While WAVERSAVER can factor out noise with frequencies as low as 0.25 Hz, five cutoff frequencies can be selected, with higher frequencies providing a faster response time. The default factory setting is 1 Hz vibration frequency immunity.

Integrated Technician™

The HI 1756 nDF Integrated Technician™ (IT®) is built-in system diagnostics that makes it possible to diagnose weighing system problems. IT allows the reading of individual load sensor voltages and weights and isolates individual system components for quick and easy troubleshooting.

Digital Volt Meter (DVM) - Option

DVM requires the HI 215IT Series Junction Box to monitor mV/V readings for each load sensor and the total system. When the operator detects a problem, the DVM readings help to isolate the faulty component. Further, the DVM readings can be used to level a system and to make corner adjustments to platform scales. Accuracy is +/- 2% or better of full scale.

NOTE If you do not have the HI 215IT Junction Box connected to the module, the reading is the

total for all load cells on the system.

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Chapter 1

Start Refill Weight

Stop Refill Weight

1756-1DF

Weight value

Dispense Valve Control

RA1

RB1

Refill Valve Control

Weighing System Tests - Optional

This test is used to diagnose drifting or unstable weight reading problems. It requires the HI 215IT Series Junction Box for full utilization. The ability to read the weight seen by the individual load sensors allows you to use this test for making cornering, leveling and load sharing adjustments to the weighing system.

The Weighing System Test provides the following problem detection support:

1. Disconnects the controller and engages an internal reference signal to see if the

problem is inside of the instrument.

2. Disconnects the load sensors and engages an internal (in the junction box)

reference signal to see if the cable between the instrument and the Junction Box is causing the problem.

3. Reads the weight of each load sensor to see if the load sensor might be causing

the problem.

Automatic or Manual Refill

Automatic refill uses user-selectable refill points to start and stop the refill process between dispense cycles. Automatic refill is only set for Dispense single speed mode. The relay B is the default refill relay in single mode and dribble feed in the dual mode. A command status of -1 will be set when the automatic refill is incorrectly configured. Automatic refill is not usable in the filler mode as the refill source vessel weight is not monitored by the HI 1756 nDF.

In the automatic refill mode, if weight at the end of a single speed dispense cycle is equal to or below the start refill weight parameter value, then the dispense cycle is disabled and the refill cycle started automatically; once the weight reaches the stop refill weight parameter value the refill cycle is stopped. Once the refill cycle is complete the dispense cycle is once again enabled. In this mode relay RA on the weigh scale channel would be used for the dispense cycle and relay RB on the same weigh scale channel would be used for the refill cycle.

An Automatic Refill Example

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Chapter 1

The Manual Refill option allows for manual refill at any time, via the STARTREFILL command; the refill cycle will automatically stop when the weight reaches the stop refill weight parameter value. The STOP command will set both relays to their default (OPEN) state.

The SETRELAY command can also be used to directly control the relay states regardless of weight value.

In the filler mode the PLC will need to remotely detect the level in the dispensing vessel and implement a manual refill operation.

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Chapter 2

Chapter 2 Specifications

● ● ● ● ● Chapter 2 provides specifications for the HI 1756 nDF Dispenser-Filler and other equipment that may come with the package. The specifications listed are designed to assist in the installation, operation and troubleshooting of the instrument. All service personnel should be familiar with this section before installing or repairing the instrument.

Basic Specifications

General

Resolution

Internal:1:8,388,608

Input

Up to four 350-ohm Full Wheatstone Bridge, Strain Gauge Load Sensor/Cells (5 volt excitation) can be connected to each weigh scale channel

Non-Linearity

0.0015% of Full Scale

Common-Mode Rejection

110dB at or below 60 Hz

Common-Mode Voltage Range

2.5VDC maximum (with respect to earth ground)

Backplane Input Voltage

5 VDC and 24 VDC

Backplane Current Load

<1 Amp at 5 VDC

0.0125 Amps at 24 VDC (with 4-350 Ohm Load Cells)

Backplane Power Load

< 5W at 5 VDC < .3W at 24 VDC with 4-350 Ohm Load Cells

C2 Calibration Input

Isolation from digital section 1000 VDC minimum.

Cable lengths

1000 feet maximum of C2 authorized cable 250 feet maximum of C2 authorized cable (Maximum of 4 load sensors) with IT Junction box.

Load Cell Excitation

5 VDC +/- 1.15 VDC maximum. Isolation from digital section 1000 VDC minimum

C2 Calibration Output

Isolation from digital section 1000 VDC minimum

Number of Channels

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Chapter 2

HI 1756 1DF 1 Weigh Scale Channel HI 1756 2DF 2 Weigh Scale Channels

Update Rate

95(10.5ms) or 145(6.9ms) Updates per Second

Averages

1-255 User-selectable in Single Increments

WAVERSAVER®

User Selectable OFF

7.50 Hz

3.50 Hz

1.00 Hz (Default)

0.50 Hz

0.25 Hz Digital Voltmeter (Integrated Technician – Diagnostic Mode Only)

Accuracy ± 2% of full scale

Relay

Two integrated solid state DC or AC relays per weigh scale channel Default state of relays will be OPEN (Form A - NO). For resistive loads only. Cannot mix AC and DC relays on same module.

DC Relay

Capable of switching 5 to 30 VDC Maximum current rating 3A @ 25oC, 2A @ 40oC, and 1A @ 60oC Minimum load current 2mA

AC Relay

Capable of switching 24-280 (47-63Hz) VAC Maximum current rating 0.5A @ 60oC Minimum load current 70mA

Environmental Requirements

Operating Temperature Range

0 to 60º C (32º F to 140º F)

Temperature Coefficient

Less than 0.005% of full scale per degree C for Cal-LO and Cal-HI reference points

Storage Temperature Range

-40 to 85º C (-40 to 185º F)

Humidity Range

0-90% (non-condensing)

Pending Approvals

UL, CUL, and CE

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Chapter 3

Step 1. Make sure that the module is

oriented correctly for installation.

Step 2. Gently slide the module into the

Chassis.

Step 3. Slide the digital board between the

PCB Guides on the top plate and bottom plate of the chassis to line up the module connector with the backplane connector

Inserting the module

Chapter 3 Installation

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Chapter 3 covers unpacking, cabling, interconnecting, configuring, and installing the Weigh Scale Module. User and service personnel should read this chapter before installing or operating the Weigh Scale module.

Unpacking

Step 1. Before signing the packing slip, inspect the packing and contents for damage of

any kind. Report any damage to the carrier company immediately.

Step 2. Verify that everything in the package matches the bill of lading. Step 3. Write down the Model and Serial number of the module. Store this information

in a convenient location for reference when contacting The Customer Support Department for parts or service.

Step 4. Be sure to complete the warranty registration on the Hardy web site.

Installing the HI 1756 nDF

Allen-Bradley ControlLogix Processor or Remote Rack

WARNING Electrostatic discharge may damage semiconductor components in the module. DO NOT

TOUCH THE CONNECTOR PINS, and observe the following handling precautions:

Wear an approved wrist-strap grounding device when handling the module. Touch a grounded object or surface to rid yourself of any electrostatic

discharged prior to handling the module.

Handle the module from the bezel in front away from the connector. Do not

touch the connector pins.

Do not install the module right next to an AC or high voltage DC module. Route all the load voltage cables away from high voltage cables.

A ControlLogix Chassis

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Chapter 3

Module release(s)

Module installed in chassis

The I/O connector at the front of the module connects the module to a load sensor, or the HI 215IT Series Junction Box, depending on how many load sensors are installed in the weighing system. (See the pin-out diagram below.) A pinout diagram is also located on the inside of the module door.

Open the module door to access to the I/O connector.

Step 1. Install the cable and connector so it allows the module door to be shut.

Step 2. With the plug oriented correctly (See the pin-out diagram below), plug the I/O male connector into the I/O connector at the front of the module.

HI 1756 1DF with door open

Step 4. When the module connector is touching the backplane connector, firmly but

carefully push toward the chassis until the pins are plugged in and the top and bottom module releases are snapped into place.

Removing the Module from the Chassis

Step 1. Press down on the top and bottom module releases simultaneously until the

module can be pulled away from the chassis. (See Figure above.)

Step 2. Pull the module out of the chassis. Step 3. Store in a safe, secure location in an anti-static bag or the original enclosure.

Installing the Module I/O Connector

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Chapter 3

Check to be sure that the connector is completely plugged in before operating the module.

NOTE Most module-related problems are due to loose

connections. Be sure to check the I/O connection first in the event you have a problem receiving information from the load cells or if the relays do not operate correctly.

Single Channel

Pin 1 Exc+

Pin 2 Sense+

Pin 3 Sig+

Pin 4 Sig-

Pin 5 Sense-

Pin 6 Exc-

Pin 7 C2+

Pin 8 C2-

Pin 9 Shield

Industry standard load cells wiring

Hardy load sensor/c2 wiring

+Exc

-Exc

+Sen

+Sig

-Sig

-Sen

+C2

-C2

Shield

RA1 IP

RA1 OP

RA1 COM

RB1 IP

RB1 OP

RB1 COM

1756-1DF

Shield

Load Cell

(0-24Vdc, 3.5A)

Valve

(0-24Vdc, 3.5A)

Valve

Control Voltage 2

Control Voltage 1

COM2

COM1

Load Cell Wiring Diagrams

The diagrams below show how Hardy Load Sensor with C2 wiring differs from standard Load Cell wiring. C2 wiring is required when using a Integrated Technician summing junction box. The C2 wires are used fro communicating IT and C2 commands.

HI 1756 1DF Valve wiring diagram

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Chapter 3

L o a d C e l

C o n n e c t o r

1756 1DF

The simple wiring diagram above shows how to connect a single load cell to a single channel 1756 1DF module. Note, when connecting the 1756 1DF to a junction box, the sense lines would be connected to +Sen and –Sen Connections in the diagram.

The solid state relays used in the 1756 nDF require a 2mA minimum load. When switching a light load with a solid state relay across the line, you must look at the rated dropout current of the load. If it is less than 2mA it may not turn off. The solution is to put a loading resistor in parallel with the light load, to be sure leakage current is sufficient to the solid state relay is turned off.

CAUTION: INSTRUMENT POWER AND RELAY WIRES SHOULD BE ROUTED AWAY FROM ALL

OTHER SIGNAL CABLES TO AVOID ELECTRICAL INTERFERENCE.

Hardy HI 215IT Junction Box

Hardy HI 215IT Junction Box Wiring Diagram

NOTE When connecting the Hardy HI 215IT Junction Box, you must remove the two factory

installed jumpers on pins 1&2 and on pins 5&6 on the module and install C2 and sense wires. C2 wires carry the commands for Integrated Technician and the C2 calibration information.

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Chapter 4

To make or change settings, there must be power to both the PLC and the module. Verify that the LEDs are lit for normal operation.

Module LEDs

Chapter 4 Configuration

● ● ● ● ●

Chapter 4 covers the settings used to prepare the controller for calibration and operation. The Setup procedures require Allen-Bradley’s RS Logix 5000, Allen-Bradley RSLinx™ or RSLinx™ Lite.

Power Check

LEDs

Scale Data LEDs

Flashing Green Dispenser/Filler is active (on) Steady Green Running (Normal) Steady Red Device Failure. Contact HI Customer Support Flashing Red Read Convert Error. LED is Off Channel is Inactive

OK Module Status LED

Brief Steady During power up the LED lights Red for about one second. Flashing Green In Program mode. (Normal) Steady Green In Run Mode. (Normal) Steady Red Device Failure. Contact HI Customer Support. Flashing Red Communication Error. At power-up, the module runs through an initial self-diagnostic check. If the module does

not have valid calibration data the scale data LED will flash green at a rate of about once a second.

The door will open to the right revealing two groups of connectors and one red button for C2 calibration at the “cal low weight” parameter value. The number of pins in the connector will depend on the number of channel options obtained. The left group of connectors will be for weigh scale inputs and the group of connectors on the right will be for relay I/O.

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Chapter 4

Display

Comment

Not Active, OPEN

Active, CLOSED

Not being used

Dot Matrix Display

Four 3x7 dot matrix displays provide individual status on the relays assigned to each weigh scale channel.

The three operational states are defined in the following table.

Setting Up Communications

Configuring the HI 1756-nDF Dispenser Filler Module in the RSLogix 5000 for ControlLogix with the HI 1756-nDF Module Add on Profile

To set up communications between the ControlLogix processor and the dispenser/Filler Control module using the Add on Profile (AOP), you will need to do the following in RSLogix 5000.

Step 1. Download the AOP files from the Hardy Process Solutions web site,

hardysolutions.com and install.

Note: If a password is requested use hi1756 (all lower case).

Step 2. Under the project, right click on the I/O Configuration and from the list box

select “New Module”. The “Select Module Type” dialog box appears.

Step 3. Scroll down and find the “Hardy” modules and expand this category. Select the

HI 1756-nDF module and click on the OK button. The module properties dialog box appears.

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Chapter 4

Step 4. Click in the Name text field. Enter a descriptive name for the module. We used

HI1756DF for example. Click in the Description box and enter a description if desired. Insure the slot selection is correct.

Step 5. If you have a dual channel module, you should click on the “Change” button and

select “Two Channel”.

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Chapter 4

Step 6. On the Connection tab, set the RPI time to 10.0 ms.

The remaining tabs will allow the user to fill out the parameter settings for the module.

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Chapter 4

Linking the PLC with the HI 1756-nDF Dispenser Filler Control Module

To set parameters for the weigh scale module, you must establish communications with a ControlLogix PLC. Follow the steps below to set up the communication link without using the AOP. You will need a new or open RS Logix® 5000 project. For instructions, see your RS LOGIX 5000 manual.

Step 1. Look for a list of folders on the left side of the screen. Scroll to and select the

I/O Config folder, which will open a menu.

Step 2. Select New Module to display a list of modules. Step 3. Select the Generic 1756 module to open the Module Properties form. Step 4. Enter the following connection parameters in the appropriate fields:

Name of Module Description of Module (Optional) Slot ID Input Assembly Instance:101 Size = 16 Output Assembly Instance: 100 Size = 16 Configuration Assembly Instance: 102 Size = 200 for a single channel

(1756 1DF) or 400 for a dual channel (1756 2DF)

Step 5. Select DATA REAL from the Comm Format pull-down list. Step 6. Open the Connection Tab. Step 7. Set the RPI to 5 milliseconds or greater Do not set this parameter lower than 5

milliseconds.

Step 8. Click Finish.

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Chapter 4

Weigh Filter NumAVg

Weight

Conditioning

Weight

Calculation

Weight Value

Flow Rate

Calculation

Flow Rate Time Base

Weight Unit

Flow Rate

Filter

Flow Rate Value

Load Cell

Signal

Flow Rate Update Period Flow Rate Filter Material

ADC

Weight Update Rate

Current Flow Rate

Auto_Preact

Calculation

Auto_Preact

stable capture time

p gain i gain frc tolerance

variation capture steady period

auto preact config start wait fast adjust

Overview of Operation

The HI 1756 nDF will calculate Gross weight, Net weight, & Flow Rate (FR) outputs simultaneously, as shown in the simplified block diagram below.

Overview of Weight Calculation

The ADC data can be filtered to reduce short term disturbances caused by system noise, vibration noise, and local short term disturbances that could affect the weigh measurement.

The most robust method to reduce these system disturbances is Waversaver®, but this mode has the longest delay which is directly proportional to the bandwidth selected as the algorithm requires at least one full cycle of the lowest frequency to be able to remove the noise and harmonics from the weight measurement. On the other hand the raw data sample mode provides the fastest response with no additional delay but does not filter out any noise from the sampled data. As a compromise a low pass filter can be selected to provide noise shaping across multiple samples centered on the current weigh value; this mode has a fixed delay of 100mS.

The filter selection will depend upon the environment and the desired response time to changes in weight.

Simplified block diagram for the 1756-1DF

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Chapter 4

Weight Filter

Delay (ms)

Quality Comment

0 0 Poor, no filtering

100

Fair, narrow filter window

270 – 2000

Excellent, Waversaver® filter selection

Parameter

Default

Description

steady period

128

Sets the number of samples used to calculate the steady weight value used in the auto-preact function.

variation

Sets the peak to peak variation in weight values which will be processed

capture

Sets the peak to peak variation in processed weight values that will be used to calculate the weight value on the scale after in flight material has settled.

Note: ADC delay in not included in delay calculation as this delay is

consistent regardless of filter mode selected.

In addition a second filtering stage can be enabled which averages the current and preceding ADC samples. This is a simple method to remove harmonics from the data stream without introducing delay into the data path. For example, if NumAverages parameter is set to 10 (default) and the weight update rate is 100Hz, a frequency notch will occur every 10Hz in the sampled spectrum. This simple but effective filter is ideal for removing harmonics at known frequencies within the sampled spectrum.

To calculate the preact value to compensate for in flight material, it is necessary to set tolerances so that the weight processing algorithm can detect when amount of inflight material falls within a user specified tolerance over a set number of samples. The required parameters are shown in the following table. This processing does not add delay into the signal processing path.

*1: Default value set to 1/2,500 of maximum capacity of the load cell. *2: Default value set to 1/10,000 of maximum capacity of the load cell

Overview of Flow Rate Control

The default setting for the flow rate will be kilograms per second (kg/sec); however the time interval will be programmable to also include kilograms per minute (kg/min) and kilograms per hour (kg/hr) and the weight value can be programmed to be in pounds enabling lbs/sec, lbs/min, and lbs/hr flow rate to be generated.

The flow rate calculation is a filtering operation tailored to provide an accurate measurement of the material flow rate over the specified period of time. As the update period is typically faster than the flow rate unit of time, the HI-1756 nDF will scale the current calculation to match the programmed flow rate unit of time, albeit hours, minutes, or seconds.

The time base value sets the number of samples that will be reviewed each time a flow rate calculation is made.

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Chapter 4

Parameter

Default

Description

Weight Unit

Weight unit selection

Value

Frequency (Hz)

Pounds(lb)

Ounces(oz)

Ton(ton) short ton

Kilograms(kg)

Grams(g)

Metric Tonnes (t) long ton

Flow Rate Period

Flow Rate options

Ref#

FR unit of time

seconds

minutes

hours

Weight Filter

The weigh scale data used in the weight calculation can be derived from one of three filters. The selection is based on a compromise between the response time required and the inherent noise within the measured value.

FILT

Function

Raw ADC data samples

Low Pass filter

Waversaver output data

Material

The material texture can cause fluctuations in the instantaneous weight readings. To compensate for these periodic fluctuations set to 0 for liquids and fine materials and 1 for coarse materials.

The flow rate is affected by the composition of the material, for example liquids will

provide a linear flow rate as they are dispensed compared to “lumpy” material which due

to product binding and asymmetric shape will cause short term disturbances in the weigh reading and subsequent flow rate calculations.

To provide a reliable flow rate reading with a range of materials the following four flows rate filters are provided, see the “flow Rate Filter” parameter in the table below.

Parameters for configuring the flow rate calculation are detailed in the following tables:

DINT Configuration Parameters used in Flow Rate Control

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Chapter 4

Parameter

Default

Description

Flow Rate Filter

The weight data used in the flow rate calculation can be derived from one of four filters. The selection is based on a compromise between the response time required and the inherent noise within the measured value.

FRF

Quality Comment

No suppression of flow rate fluctuations caused by system noise, fast response time to step change in flow rate

Adaptive Flow Rate Filter (default) Very good at suppressing flow rate

fluctuations caused by system noise, and has a fast response time to step change in flow rate

Long Term Non-Adaptive Filter Excellent at suppressing flow rate fluctuations

caused by system noise, but has a long response time to step changes in flow rate

Short Term Non-Adaptive Filter Very Good at suppressing flow rate

fluctuations caused by system noise, and has a short response time to step changes in flow rate

Parameter

Default

Description

Flow Rate Timebase

4.0

Period of time over which changes in weight are used to calculate the flow rate. The smallest increment is 100ms.

Unit of time is in seconds.

REAL Configuration Parameters used in Flow Rate Control

Overview of Relay Operation

After power up all relay outputs are in the OPEN state, which is assumed to indicate that the external valves are CLOSED, and will remain in the OPEN state until the unit is programmed via the output table.

There are two programmable set points per weigh scale channel; each set point is associated with a relay output. As the 1756 nDF can be a single or dual channel and the operation of each channel is independent, the relays, target weight and preact values used on each channel will be referenced as relay RA, target TA, preact PA, relay RB, target TB, and preact PB.

The HI 1756 nDF implements a change in weight (CIW) algorithm, which requires that the external system controls if the weight will increase (fill) or decrease (dispense) and the HI 1756 nDF simply treats the net weight as an absolute value with respect to the zero

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Ref#

Relay Mode

Description of Relay Operation

Single Relay Operation

Relay RA is set to the CLOSED state at the beginning of the fill cycle. Relay RB is held in the OPEN state. When the absolute net weight value is greater than or equal to the SPA value relay RA is set to the OPEN state. RB is the refill relay. SPA = target weight TA – preact PA SPB = 0.0

point. The preact value can be positive or negative, to compensate for in flight material, to ensure the set point operates at the correct absolute net weight value.

The relay’s initial state, OPEN or CLOSED, is determined by mode of operation. The

dynamic state of the relay during a fill cycle depends on the comparison of the current net weight to the calculated set point value. The set point value is based on three parameters the target weight, the preact weight, and the mode of operation. These parameters are defined below:

1. The “target weight” The target weight is a floating point number indicating the nominal weight value that

should OPEN or CLOSE the relay depending on the mode of operation. Regardless of mode it is recommended that each fill cycle should start with a TARE

command to set the net weight to zero.

2. The “preact” value In order to compensate for delays caused by sensor reaction time or in flight material,

there is a preact parameter. The preact value is subtracted from the target weight so negative preact values will increase the set point weight value with respect to the target weight value, and positive values will decrease the set point weight value with respect to the target weight value.

3. The “mode of operation” In the following description when the relay is OPEN the external valve will be CLOSED,

and when the relay is CLOSED the external valve will be OPEN. The initial state of each relay and the set point calculation depends upon the mode of

operation. Once a relay has been closed it will not be opened until the next start or restart of a fill cycle.

The sequential mode is defined as the two relays working sequentially; with relay RA being active before relay RB. In this mode the two relays cannot be CLOSED at the same time. This mode could be used to select between two different flow rates into one hopper.

The parallel mode enables each relay to operate independently enabling two feeders at different speeds to be used to fill a single hopper with the same ingredient.

The different modes of operation, for each weigh scale input, are detailed in the following table; where the Ref# value refers to the mode value used to select the desired mode of operation.

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Ref#

Relay Mode

Description of Relay Operation

Sequential Relay Operation

Relay RA is set to the CLOSED state, and relay RB set to the OPEN state at the beginning of the fill cycle. When the absolute net weight value is greater than or equal to the set point SPA relay RA is OPEN and relay RB is CLOSED, when the absolute net weight value is greater than or equal to set point SPB both relays are OPEN. Automatic refill not allowed. SPA = target weight TA – preact PA SPB = target weight TB – preact PB

Parallel Relay Operation

[Default Mode of Operation for each weigh scale] Relay RA and relay RB are both set to the CLOSED state at the beginning of the fill cycle. When the absolute net weight value is greater or equal to set point SPA relay RA is OPEN or when the absolute net weight value is greater or equal to set point SPB relay RB is OPEN. Automatic refill not allowed. SPA = target weight TA – preact PA SPB = target weight TB – preact PB

2 Speed (Fast/Slow) Mode Considerations

The 1756-nDF can be purchased with two relays per weigh scale channel. The architecture can be configured so both relays start at the same time (simultaneous feed)

and have different target weights so the “fast” feed is closed before the “slow” feed; or

the two relays can start sequentially (sequential feed) with the “fast” relay (relay A) being

closed when it reaches its target weight and the ‘slow” relay (relay B) opening as soon as

the “fast” relay is closed. Automatic refill not allowed. In both situations the “fast” relay will never see a stable weight on the scale before the

“slow” relay allows additional material onto the scale. Therefore the “fast” relay will be

treated as a coarse adjustment and will be set to provide a maximum percentage of the final target weight value, and the auto-preact algorithm will run only on the slow relay to provide the accurate final dispense cycle to reach the desired target weight.

When setting up the process for the first time the “fast” relay should be run on its own with the “slow” relay initially disabled; the target weight for the “fast” relay will be set by running several test dispense cycles. Once the “fast” relay target is set, the slow relay will be enabled and tests repeated to verify that the vessel does not overfill. If this occurs, one of two actions can occur:

1. If the auto-preact is at zero or below the “fast adjust” percentage of the target

weight then the fast relay target has been programmed too high. If the “fast

adjust” value is not 0.0% then the target weight set for the “fast” relay will be

reduced by the percentage programmed into the “fast adjust” parameter and the auto-preact reduced by the same percentage or reset to zero if the residual value in the auto-preact output is below the “fast adjust” percentage times the target weight value. This repeats until the unit hits the desired target weight.

2. If the “fast adjust” bit is set 0.0%, then the control system is expected to monitor

the error between the final weight and the desired target weight and should reduce the fast relays target value. Any change in the fast relay target value resets the auto-preact value to zero.

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Parameter

Default

Description

capture averages

Sets the number of fill/dispense cycles to average the target error values and flow rate values to provide the auto_preact value.

auto preact enable

Selects between the internally calculated auto-preact value and the external preact value in the output table.

Parameter

Default

Description

start wait

2.0

Period of time that the flow rate is ignored in the autopreact calculation

update time

2.0

Period of time after the setpoint value has been reached that a new weight input can be taken to update the auto-preact function.

stable

1.0

The maximum peak to peak percentage difference in flow rate used to detect a stable flow rate.

Overview of Auto-Preact Function

The auto_preact function predicts the required preact weight to ensure that the weight on the scale at the end of a fill cycle is equal to the desired target weight, after all the inflight material has cleared the physical pathways and settled on to the scale. The setpoint weight is the weight at which the relay is closed, and is calculated by subtracting the preact weight from the desired target weight.

Setpoint weight = target weight – auto_preact weight At the beginning of the fill cycle the material flow rate is not linear and the start wait

parameter is used to ignore the flow rate during this time. Once the calculated setpoint has been reached the relay will close the valve and any in flight material will continue to accumulate on the scale for a short period of time. The update time parameter is used to set the predicted time for the inflight material to settle onto the scale so a reliable weight reading can be taken.

This weight value is used in the auto-preact function to continually modify the setpoint value so the correct target weight is reached.

The auto-preact function combines a proportional plus integral filter based on historical differences between the target weight and the weight measured on the scale at the end of each fill cycle; and a predictive function based on the current flow rate.

The following parameters are used to configure the auto-preact function.

DINT Configuration Parameters used in Auto-Preact

REAL Configuration Parameters used in Auto-Preact

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Parameter

Default

Description

p gain

0.05

Proportional error term gain value. Additional percentage of the error added to the amount of correction the module is making.

i gain

0.65

Integral error term gain value. The percentage of the error being applied to the auto preact.

frc tolerance

2.0

The minimum peak to peak percentage difference in flow rate used to detect a stable flow rate. Values below this are ignored

fast adjust

1.0

If the channel is being used in a simultaneous or sequential feed mode this sets the percentage of target weight that can be adjusted on the fast channel if the final measured weight exceeds the target weight.

Parameter

Description

fast setpoint time

Actual time from the start of the fill cycle to when the relay on the fast channel changes state.

slow setpoint time

Actual time from the start of the fill cycle to when the relay on the slow channel changes state.

stable time

Time from the start of the fill cycle to the flow rate becoming stable. Unit of time is in seconds.

steady time

Time from when the target weight is reached (relay triggered) to when the weight first remains within the capture tolerance for the programmed number of steady periods.

Unit of time is in seconds.

not stable

A value of ONE indicates that the flow rate did not become stable during the fill cycle; otherwise this status value is ZERO.

not steady

A value of ONE indicates that the weight did not remain within the capture tolerance on the scale for the specified number of update periods, update time, before the capture time was reached; otherwise this status value is ZERO.

Status Values used in Auto-Preact function

Use of Auto-Preact Status Values

The minimum time to complete an auto_preact cycle is the sum of the slow setpoint time and capture time values. The slow setpoint time value is the time from the start of the fill

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cycle to when the relay changes state, and the capture time is the time from when the relay changes state to when a weight value is taken (assumed to be available) to update the auto_preact function. The following status values help to ensure the system timing is configured correctly. A full picture of the cycle can be calculated by externally monitoring the time from the start of the fill cycle to when the cycle ends.

Flow Rate Status

The flow rate compensation portion of the algorithm requires a constant, stable, flow rate to be able to calculate the required value to compensate for in-flight material after the relay changes state. If the not stable status value is a one, then the flow rate never became stable before the relay changed state. This could be caused by one of the following reasons:

1. The stable tolerance is too tight and the material is unable to meet the specified

percentage variation during the fill cycle.

2. The start wait value is too long and the period left to calculate a stable flow is

too short. This can be verified by reading the stable time and slow setpoint time values. If the stable time is shorter than the start wait period, and is also less than the setpoint time then the start wait time needs to be adjusted to provide at least 2 timebase periods between the measured stable time and slow setpoint time values. If the slow setpoint time is less than the stable time then either the stable tolerance or the material flow rate needs to be adjusted.

3. The flow rate for numerous reasons was changing throughout the fill cycle. This

may be by design and once identified the user can set the frc tolerance parameter to zero, to disable this portion of the algorithm.

If the not stable status value is a zero, then the slow setpoint time provides a time reference for stable time value, if the stable time value is multiple timebase periods long, then adjustments to the flow rate could be considered to increase throughput.

Auto_preact Status

The programmed capture time value represents the time from when the relay state is changed to when a weight value on the scale can be taken and used to adjust the auto_preact function.

If the AP_NOT_STEADY status is a one, then the weight did not remain within the capture tolerance on the scale for the specified steady period before the update time, programmed time from relay changing state, was reached. To determine possible causes, the programmed update time should be compared to the steady time status value which represents the time from when the relay changes state to the first time the weight on the scale remains within the capture tolerance for the programmed steady period. If the update time is less than the steady time status duration, then either the update time needs to be increased so that it exceeds the steady time status duration by at least 0.3 seconds to allow a stable weight value to be calculated; or the update time needs to be increased so a reliable weight value is available sooner. While the not steady status is a one, the auto_preact value is not being updated. When adjusting the update time the auto_preact values should be reset.

If the update time is greater than the steady time and the not steady value is zero, then the system will stabilize and the correct auto_preact value will be generated to optimize the process.

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Input table offset

Content

Command (echoes the command given in the Output Table. See below)

Command Status (see below)

Parameter value, in read and write commands

Target Value for relay A (TA)

Gross weight

Net weight

Rate of change

STATUSWORD

Input table offset

Content

Command (echoes the command given in the Output Table. See below)

Command Status (see below)

Parameter value, in read and write commands

Target Value for relay A (TA)

Gross weight

Net weight

Rate of change

STATUSWORD

Assembly Object Instances

1. Input Assembly (from 1756 nDF to PLC). An area where the 1756 nDF module writes its data such as Net, Gross, FR to the PLC. The input assembly is an array of 16 floats, with 8 devoted to the 1st channel and the next

8 devoted to the 2nd channel. The rate of change and the gross and net weights are always visible in the input table, for

each weigh scale.

Input Assembly for Weigh Scale 1

Input Assembly for Weigh Scale 2 (for HI 1756 2DF only)

2. Output Assembly (from PLC to 1756 nDF) Dedicated area where PLC writes parameters to the 1756 nDF; these values are read by

the 1756 nDF as scheduled by the RPI. The output assembly defaults to an array of floats. The output table consists of 16 float values, of which the first 8 float values apply to the

1st channel, and the next 8 float values apply to the 2nd channel.

The first float value of the 8 is the “command” value. The interpretation of the next 7

values depends on the command being given.

Default Output Table Description

These commands are zero, tare, write nonvolatile, reload nonvolatile, cal low, cal high, C2 cal. These commands do not require any of the 7 other float values. These commands will use the default output table format.

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Output table offset

Content

Command

Parameter Number (used by read and write commands)

Parameter Value (used by write command and set relay command)

*spare*

4 5 6 7

Output table offset

Content

Command

Parameter Number (used by read and write commands)

Parameter Value (used by write command and set relay command)

*spare*

12 13 14 15

Default output table formats

Output Assembly for Weigh Scale 1

Output Assembly for Weigh Scale 2 (for HI 1756 2DF only)

Commands to the PLC related to weigh scale 2, input table offset 8 – 15, are only valid for HI 1756 2DF modules. For the HI 1756 1DF modules this portion of the input table will be set and held in its default NOCMD state.

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command

Number

description

NOCMD

0.0

No command

STARTANDTARE

1.0

This command causes an automatic TARE of the weigh scale, sets the relays based on the mode of operation, and calculates the two set points for relay RA and relay RB before starting the fill cycle.

Relay Mode

Description

Single Relay Mode

Sequential Relay Operation

Parallel Relay Operation

See “Overview of Relay Operation” for a detailed

description on the different modes of operation.

STARTNOTARE

2.0

This command sets the relays based on the mode of operation and updates the two set points for both relay RA and relay RB before continuing to run fill cycle.

The RESTART command does not cause an automatic TARE of the weigh scale.

Relay Mode

Description

Single Relay Mode

Sequential Relay Operation

Parallel Relay Operation

See “Overview of Relay Operation” for a detailed

description on the different modes of operation.

SET**

3.0

The SET command updates the two set points for relay RA and relay RB while continuing to run the fill cycle.

The SET command does not cause an automatic TARE of the weigh scale and does not set the relays based on the mode of operation. This is used to change the target and preact values only.

** Repeatable Command

STOP

4.0

The relays are set to their default OPEN state, and the unit continues to monitor the weight readings but ignores weight readings to ensure relays remain OPEN.

First Word – 0: Command Number

The default output table enables single parameters and functions to be modified. The majority of the commands are intended to be used once and require a NOCMD or a

different command to be sent if the same command is to be repeated. However, there are special function commands which can be repeated and each time the command is read the appropriate action is taken. These special commands are denoted using a “**” in the following table. For example the SET command enables the user to continually adjust the target weight throughout a fill or dispense cycle.

The first word in the output table is a command, the possible commands are:

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command

Number

description

SETRELAY**

7.0

Default setting is 0, both relays OPEN

Manual mode for testing relay operation. 0 = both relays RB and RA are OPEN 1 = relay RB is OPEN, and relay RA is CLOSED 2 = relay RB is CLOSED, and relay RA is OPEN 3 = both relays RB and RA are CLOSED The manual relay setting can be overridden by the STARTANDTARE and the STARTNOTARE commands.

WARNING: Forcing the relay may cause damage or personal injury. Make absolutely sure that you know what the relay is connected to before activating.

** Repeatable Command

RELOADNV

16.0

Reload Non-Volatile Recall all parameters from non volatile memory.

WRITENNV

17.0

Write Non-Volatile Save all parameters to non volatile memory.

STARTREFILL

18.0

Starts a manual refill cycle

TARECMD

98.0

TARE: zero the net weight

ZEROCMD

99.0

Zero the gross weight

CALLOWCMD

100.0

Hard calibration, low step.

CALHIGHCMD

101.0

Hard calibration, high step.

C2CALCMD

102.0

C2 calibration.

WRITEPARAM

103.0

Write a single parameter. To write a single parameter, send the command 103.0. Specify the parameter to be changed by putting the parameter number in float number 1, and put the new parameter value in float number 2 of the output table.

READPARAM**

105.0

Read a single parameter. To read a single parameter, send the command 105.0. Specify the parameter to read by putting the parameter number in float number 1. The parameter value will appear in word 2 of the input table.

** Repeatable Command

RESETFR

112.0

Clear all old data from the flow rate (FR) weight buffer. This has the effect of zeroing the flow rate value.

RESETAPCMD

113.0

Reset Auto Preact Command Resets all stored values in the auto preact function to their factory default values.

SETDEFAULT

148.0

Replaces all parameter values with the factory default parameters values.

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return codes

#Value

description

SUCCESS

0.0

Pass

NOTALLOWED

-1.0

Bad state for command, tried to run to start a cycle while refilling or trying to refill while running a dispense/fill cycle.

OUTOFTOLERANCE

-3.0

Out of tolerance

INDEXOUTOFRANGE

-4.0

Out of Range

NOSUCHCMD

-5.0

Command bad

C2FAILNODEVS

-6.0

No C2 devices

C2FAILCAPEQ

-7.0

Failure, C2 capacities not equal

HARDCALFAILCOUNTS

-8.0

Fails, too few ADC counts between high low

NOSUCHPARAM

-9.0

Parameter ID incorrect

Parameter Name

Parameter Number

Parameter Default

Description

Channel Active

1.0 1 Boolean, 1 = ON, 0 = OFF

Weight Units

2.0 3

Value

Frequency (Hz)

Pounds(lb)

Ounces(oz)

Ton(ton) short ton

Kilograms(kg)

Grams(g)

Metric Tonnes (t) long ton

NumAverages

3.0

1 -255 Averages the current sample and previous N samples to provide the current weight value.

Command Return or Error Codes

Commands always return the command word and command status. The command status word may include the following codes:

Second and Third Words - 1, 2: Parameter Number and Value

The second and third words in the output table, Parameter Number and Parameter Value, are used by the WRITEPARAM command. For details see the Parameter Table below. Expanded descriptions are listed below the table by parameter number.

Notes When set by a command, all parameters are saved to non-volatile memory. The scale

calibrations are saved automatically when completed successfully

DINT Configuration Parameters

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Parameter Name

Parameter Number

Parameter Default

Description

Waversaver

4.0 3 Waversaver Options

Ref#

Frequency (Hz)

OFF

7.50

3.50

1.00

0.50

0.25

Zero Track enable

5.0 0 Enables the auto zero tolerance function when 1.

Weight Filter

6.0 2 Weight filter selections See Overview of Weight Calculation for

selection details.

Ref#

Filter

Raw ADC data samples

Filtered data samples

Waversaver output data

Refill mode

7.0 0 Setting to 1 the automatic refill mode is enabled and the unit automatically starts a refill cycle if the next dispense cycle will lower the weight below the programmed start refill weight value. The automatic refill cycle is stopped when the weight reaches the programmed stop refill weight value. This is only available in single relay mode. When set to 0 the manual refill mode is enabled and a STARTREFILL command is required to start the refill cycle.

Weight Update Rate

8.0 0 Sets the rate at which weight readings are taken. Set to 0 for 145Hz mode and to 1 for 95Hz mode.

Material

9.0 0 To compensate for material flow rate, set to 0 for liquids or fine materials and 1 for coarse or “lumpy” materials.

Flow Rate filter

10.0

Flow rate filter. See Overview of Flow Rate Calculation

for selection details.

Ref#

Filter

Raw ADC data samples

Adaptive running avg

Short term running avg

Long term running avg

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Parameter Name

Parameter Number

Parameter Default

Description

Flow Rate Units

11.0

Flow Rate options

Ref#

FR unit of time

seconds

minutes

hours

Flow Rate Period

12.0

Used to set when the flow rate calculation is active. When set to 0 (default), the flow rate calculation continuously runs, and when set to 1 the flow rate calculation is run only during a fill cycle.

steady period

13.0

128

When this value is set to zero the steady weight algorithm is bypassed and the weight data value is used directly.

The steady weight algorithm is enabled when a non-zero value is entered. The nonzero value sets the maximum period used to generate the steady weight output.

The valid array sizes are 16, 32, 64, and 128 (default).

auto preact enable

14.0

Configures the auto preact function. When set to 0 (default) the auto_preact is

disabled and the preact value must be entered through the output table.

If this value is set to 1the auto_preact function is enabled and the preact value from the output table is ignored; and any changes to the target weight during a feed cycle are also ignored. This ensures that the auto_preact can converge towards a fixed target weight.

Any transition to 0 causes the current state of the auto_preact function to be held. If the auto_preact is not reset through the command interface, and this value is set high the auto_preact function continues as if there was no interruption. It is therefore strongly recommended that this value is only changed between filler/dispense cycles.

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Parameter Name

Parameter Number

Parameter Default

Description

capture averages

15.0

This sets the number of fill/dispense cycles to average the target error values and flow rate values to provide the auto_preact value.

The minimum value = 1, and the maximum value = 100

Parameter 1 Channel Active

Enables or disables the weigh channel.

Parameter 2 Weight Units (Unit of Measure)

The Unit parameter sets the scale and related displays to one of the following options: 0: Pounds (lb)

1: Ounces (oz) 2: Ton (ton) short ton 3: Kilograms (kg) - Default 4: Grams (g) 5: Metric Tonnes (t) long ton Range: LB, OZ, TON, KG, G, T (default Kg)

Note The weigh scale module does not need to be recalibrated after changing the metric value.

Parameter 3 NumAverages

This is the number of samples to average when determining a value to reduce the effect of material impact and/or vibration as material moves on and off the scale. The dispenser/filler takes 95 or 145 readings per second. If you average enough weight readings, the weight loss or gain remains smooth and the displayed value shows little or no fluctuation, although it is actually recalculated (by sliding average) with each reading. If a weight reading fluctuates too much, increase the number of readings in the average, but for applications that require a very quick weight reading, do not set this value too high.

The averaging parameter is most often set when using any device that outputs an erratic signal (e.g. a flow meter). Using the averaging function comes at the expense of response time. A setting of one average takes 10 milliseconds at 95sps or 6.67milliseconds at 145sps; or at a setting of 95 the average takes 1 second at 95sps or 0.67 seconds at 145sps. The averaging function is a running average, where the input signals are totaled and the total is divided by the averaging number. The instrument reads one new signal plus the last number of averages signals and repeats the averaging process again.

For example: With a setting of 20 averages, the instrument reads the 20 most current input signals, totals the signals, divides by 20, drops the oldest one, reads one new signal along with 19 old readings, totals the signals, divides by 20, drops the oldest one, etc. The NumAverages filter is included in all weight filter modes.

Range: 1-255 (default 1) See also WAVERSAVER for information on filtering unstable weight readings.

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Parameter 4 Waversaver

Chapter one provides a detailed description of WAVERSAVER’s function and purpose. In short, WAVERSAVER helps to mitigate the effects of vibratory forces, allowing the HI 1756 nDF to distinguish between actual weight data and mechanical noise in the signals the load cell sends. WAVERSAVER can be configured to ignore noise with frequencies as low as 0.25 Hz. High values allow faster readings, while the lower values raise the degree of filtration. 7.5 Hz provides the least vibration immunity with the fastest response time. 0.25 Hz provides the most vibration immunity with the slowest response time. The function is user selectable and can be turned off. Waversaver is not used when the Weight filter is set to RAW, or Low pass filter mode.

Range: OFF, 7.50 Hz, 3.50 Hz, 1.00 Hz (Default), 0.50 Hz, 0.25 Hz

Parameter 5 Zero Track enable

Enables the auto zero tolerance function

Parameter 6 Weight filter

Selects the filter used after the analog to digital conversion stage to remove noise and harmonics from the weight value.

Parameter 7 Refill mode

This is only available in the single relay mode of operation. Relay B is used for the refill relay. Enables the automatic refill mode so the unit automatically starts a refill cycle if the next dispense cycle will lower the weight below the programmed start refill weight value. The automatic refill cycle is stopped when the weight reaches the programmed stop refill weight value. The STOP command will set both relays to their default (OPEN) state. In the manual refill mode a STARTREFILL command is required to start the refill cycle, however the refill cycle will automatically stop when the weight reaches the programmed stop refill weight value. In automatic or manual mode the STOP command will set both relays to their default (OPEN) state.

Parameter 8 Weight Update Rate

This parameter sets the update rate of the analog to digital converter, and any subsequent weight filtering calculations.

Parameter 9 Material

Defines the type of material being measured; liquids and materials that flow easily are defined as fine material, and materials that may bind together or are lumpy in texture are defined as coarse material. This selection helps to configure the flow rate calculation to remove short term disturbances in the flow rate.

Parameter 10 Flow rate filter

The type of material and the process environment may require different filtering to ensure a stable flow rate. This parameter enables one of four possible flow rate filters to be selected.

Parameter 11 Flow rate units

The units of time (seconds, minutes or hours) you want for the flow rate. The Flow Rate display on the summary display will read in these units.

Range: 0=sec, 1=min, 2=hr (default Seconds)

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Parameter Name

Parameter Number

Parameter Default

Description

Span Weight

16.0

4,000

The total amount of weight, in selected weight units, placed on the scale for the

high point when performing a “Traditional

Calibration”.

Cal low weight

17.0

0.0

Amount of test weigh, in selected weight units, used, normally zero, for the low point during hard calibration or reference point during C2 calibration.

Auto Zero tolerance

18.0

4.0

If used, the gross weight measurement value will be set to zero whenever the gross weight is within the auto zero tolerance and the scale is not in motion.

Motion tolerance

19.0

2.0

Value, in selected weight units, used to determine if the scale is in motion.

Zero tolerance

20.0

4.0

Sets the weight range, in selected weight units, around zero that will be accepted as zero by the instrument.

Tare weight

21.0

0.0

The weight value, in selected weight units, removed by the TARE function.

Start refill weight

22.0

0.0

Weight reference which will cause a refill cycle to automatically start

Stop refill weight

23.0

4,000.0

Weight at which a refill cycle will automatically stop

Parameter 12 Flow Rate Period

Parameter 13 steady period

This parameter sets the number of samples that are processed to provide the weight output.

The valid array sizes are 0, 16, 32, 64, and 128 (default). When this value is set to zero the steady weight algorithm is bypassed and the weight

data value is used directly.

Parameter 14 auto preact enable

Enables the auto-preact function

Parameter 15 capture averages

Sets the number of fill/dispense cycles to average the target error values and flow rate values to provide the auto_preact value.

REAL Configuration Parameters

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Parameter Name

Parameter Number

Parameter Default

Description

Capacity

24.0

5000.0

When the gross weight is greater than the programmed capacity value the ERROROVERCAPACITY status bit is set. This status bit is reset whenever the gross weight is below programmed capacity value.

Flow Rate Time Base

25.0

4.0

Period of time over which changes in weight are used to calculate the flow rate. Unit of time is in seconds.

26.0

Reserved

Variation

27.0

Sets the peak to peak variation in weight values which will be processed

Capture

28.0

Sets the peak to peak variation in processed weight values that will be used to calculate the weight value on the scale after in flight material has settled.

Start Wait

29.0

2.0

Period of time, from the start of the fill cycle, during which the flow rate is not calculated. The smallest increment is 0.1 seconds.

Unit of time is in seconds.

Update Time

30.0

2.0

Period of time, after the target weight has been reached before the measured weight value is taken. The smallest increment is

0.1 seconds. Unit of time is in seconds.

Stable

31.0

1.0

The maximum peak to peak percentage

difference in flow rate once the “stable wait’ period is reached. Values outside of

this range reset the calculation. If a stable flow rate is not measured the

flow rate portion of the auto-preact algorithm is not updated.

P gain

32.0

0.05

Gain value used to scale the proportional error term.

Setting this value to 0.0 disables the proportional portion of the P+I filter.

Maximum value is 1.0

I gain

33.0

0.65

Gain value used to scale the integral error term.

Setting this value to 0.0 disables the integral portion of the P+I filter; and forces the integral term to 0.0.

Maximum value is 1.0

●

Chapter 4

Parameter Name

Parameter Number

Parameter Default

Description

FRC Tolerance

34.0

2.0

Percentage changes in the flow rate changes below this value are ignored.

Setting this value to 0.0 disables portions of the auto_preact calculation related to flow rate, and resets all the flow rate terms.

Fast Adjust

35.0

1.0 If the channel is being used in a simultaneous or sequential feed mode, then this sets the percentage the fast relay is adjusted by if the auto-preact algorithm exceeds the target weight when the autopreact values are zero.

*1: Default value set to 1/2,500 of maximum capacity of the load cell. *2: Default value set to 1/10,000 of maximum capacity of the load cell

Parameter 16 Span Weight

The Span Weight is a reference point derived from an actual measured weight. This should not be confused with the Scale Capacity. If you have a 100 pound weight and you place it on the scale, the Span Weight would be 100 pounds.

Parameter 17 Cal low weight

This reference weight is the weight of any product on the scale that is not removed during calibration (derived from actual measured weight used at cal low or C2 cal). Normally, you would remove all “live load” weight from the scale to obtain a Cal low weight of 0.0.

Range: Must be > or = 0.

Parameter 18 Auto Zero tolerance

If enabled the gross weight measurement value will be set to zero whenever the gross weight is within the auto zero tolerance and the scale is not in motion

Parameter 19 Motion Tolerance

A value, based on the Weight Units parameter, used to determine if the scale is in motion

Parameter 20 Zero tolerance

This parameter sets the weight range, depending on the Weight Units parameter, around zero that will be accepted as zero by the instrument.

Parameter 21 Tare weight

The weight value based on the Weight Units parameter, below which will be removed by the TARE function.

Parameter 22 Start refill weight

If the current weight, after a dispense cycle, is equal to or below this weight reference value then the refill cycle to automatically start. In situations where the weight at the end of a dispense cycle will be equal to or below the start refill weight parameter value, the dispense cycle is disabled and the refill cycle started automatically Value must be equal to or greater than 0.0 (default) and less than the stop refill weight

4000.0 (default)

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Chapter 4

Parameter 23 Stop refill weight

Weight at which a refill cycle will automatically stop Value must be greater than 0.0 (default) and equal to or less than the stop refill weight

4000.0 (default)

Parameter 24 Capacity

When the gross weight is greater than the programmed capacity value the ERROROVERCAPACITY status bit is set. This status bit is reset whenever the gross weight is below programmed capacity value.

Parameter 25 Flow rate time base

The Time Base is the length of time in seconds between two weight readings that are subtracted to determine the initial flow rate. By increasing the time base, you increase the time between weight readings. This allows more material to be dispensed during the time base period. Low flow rates require a longer time base than high flow rates. The controller measures weight to about 1 part in 10,000. The formula below provides a minimum.

TIME BASE > (SCALE CAPACITY/10000)/LOW SETPOINT (units per sec.) SCALE CAPACITY/5000 = determines minimum weight increment

Parameter 26 Reserved.

Parameter 27 variation

Sets the peak to peak variance value below which samples are filtered.

Parameter 28 capture

Sets the peak to peak variance value used to select which filter is used to provide the output value.

Parameter 29 start wait

Period of time, from the start of the fill cycle, during which the flow rate is not calculated.

Parameter 30 Update Time

Period of time, after the target weight has been reached before the measured weight value is taken.

Parameter 31 stable

Sets the maximum peak to peak percentage difference in flow rate, once the “stable wait’ period is reached. Values outside of this range reset the calculation.

●

Chapter 4

Parameter Name

Parameter Number

Description

Historical Flow Rate

55.0

The averaged flow rate value. The period over which this value is calculated is set by the capture averages parameter.

Preact A

56.0

The current preact value for relay A

Preact B

57.0

The current preact value for relay B

Last Flow Rate

58.0

The flow rate from the last fill/dispense cycle

Last Fill Weight

59.0

The measured weight at the end of the last fill/dispense cycle

Parameter 32 p gain

Gain value used to scale the proportional error term. The proportional error term is generated by scaling the difference between the

programmed target weight and the final weight value measured on the scale at the end of the last fill/dispense cycle. The larger the p_gain value, the faster the loop will compensate for a constant step change in the process but the larger the error will be for random fluctuations in the process.

The p_gain value can be programmed to a maximum value of 1.0, which represent 100% of the measured error or to 0.0 which disables the proportional compensation in the P+I calculation.

Parameter 33 i gain

Gain value used to scale the integral error term. The integral error term measures the difference between the programmed target weight

and the final weight value measured on the scale at the end of the last cycle, but instead of making a single change to the auto_preact value this error is integrated over multiple fill/dispense cycles. In cases where a step change in the process are encountered the integral term will eventually reach the desired weight value and the target error will diminish to zero. In this situation as the target error value tends towards zero the impact on the preact value is also reduced so the response of the system is directly proportional to the i_gain value used.

The i_gain value can be programmed to a maximum value of 1.0, which represent 100% of the measured error or to 0.0 which disables the integral compensation in the P+I calculation.

Parameter 34 frc tolerance

Percentage changes in the flow rate changes below this value are ignored and no changes to the auto_preact value are made.

Parameter 35 fast adjust

If the channel is being used in a simultaneous or sequential feed mode, then this sets the percentage the fast relay is adjusted by if the auto preact algorithm exceeds the target weight.

REAL Status Values

●

Chapter 4

Parameter Name

Parameter Number

Description

Steady Time

60.0

Time from when the target weight is reached (relay triggered) to when the weight first remains within the capture tolerance for the programmed number of update periods, update time.

Unit of time is in seconds.

Cycle Time

61.0

Time form the start to the end of the fill/dispense cycle Unit of time is in seconds.

Stable Time

62.0

Time from the start of the fill cycle to the flow rate becoming stable. Unit of time is in seconds.

Fast Setpoint Time

63.0

Time from the start of the fill cycle to when the relay on the fast channel (relay A) changes state.

SlowSetpoint Time

64.0

Time from the start of the fill cycle to when the relay on the slow channel (relay B) changes state.

Averaged preact value

65.0

Averaged preact value

Output table offset

Content

Command – START, RESTART, SET, and STOP

Mode of operation (weigh scale 1)

Target weight TA for relay RA

Preact value PA for relay RA

Target weight for relay RB

Preact value for relay RB

6 7 8

Command – START, RESTART, SET, and STOP

Mode of operation (weigh scale 2)

Target weight TA for relay RA

Preact value PA for relay RA

Target weight for relay RB

Preact value for relay RB

14 15

Dynamic Output Table Description

The following commands will enable the user to read and write the parameters of the 1756 nDF during a fill cycle. These commands allow multiple parameter values and associated functions to be modified within a single command.

See the “overview of Relay Operation” section to determine the correct Mode of

Operation value listed in the dynamic output table.

Dynamic output table format

●

Chapter 4

Status Word

Value

Definition

STATUSCHANENABLED

0x00800000

Set if channel enabled

STATUSINMOTION

0x00400000

Variations in weight exceed the motion tolerance parameter

ERRORADCONVERT

0x00200000

Millivolt return from the load cell system is out of range for the unit

ERRORADFAILURE

0x00100000

Unit’s A/D converter not

responding.

ERROROVERCAPACITY

0x00080000

Out of range value

ERROR_EPROM

0x00000400

EPROM hardware error

STATUS_AP_WT_NOT_STEADY

0x00000100

Indicates if the current sample is within tolerance.

STATUS_AP_NOT_STABLE

0x00000080

Set if flow rate was not stable. Remains set until the start of the next fill cycle

STATUS_AP_NOT_STEADY

0x00000040

Set if weight on the scale was not within tolerance at the end of the fill cycle. Remains set until the start of the next fill cycle

STATUS_AP_WAITING

0x00000020

Set after the last relay closes and remains set until the weight sample is taken

STATUS_AP_ACTIVE

0x00000010

Set during the entire fill cycle, if auto preact enabled

STATUS_REFIL

0x00000008

Refill process active

STATUS_ON

0x00000004

System ON or OFF

RELAYB_ASSERTED

0x00000002

Relay B is asserted

REALYA_ASSERTED

0x00000001

Relay A is asserted

Commands for weigh scale 2 from the PLC, output table offset 8 – 15, are only valid for HI 1756 2DF modules. For the HI 1756 1DF modules this portion of the dynamic output table will be ignored.

Status Word

The “status word” is a bit encoded value within the integer number.

*Dual Mode and auto refill ON, or in the auto refill mode where the target weight greater than the difference between refill low and refill high or trying to start while the scale is in motion.

Integrated Technician

If there is NO IT JBOX, the instrument can still measure the sense voltage, the overall load cell millivolts per volt, and the internal reference weight value. If the user has an IT JBOX, the instrument can also read the weights and voltages of the individual sensors attached to the IT JBOX.

To initiate an IT test; do a WRITEPARAM command, with parameter number 0x0036, and a parameter value equal to the number of sensors, which should be 1-4 if you have an IT JBOX. If you do not have an IT JBOX, the parameter value does not matter.

To read back the results, do a READPARAM command, with parameter numbers 0x0036, 0x1036, 0xB036. The return values are listed below.

●

Chapter 4

Return Value

REAL

Description

INSTANCE_VSENSE {XE “INSTANCE IT Return Values}

54.0

Sense voltage, 2 decimal places

INSTANCE_DVM_COMBINED

4150.0

millivolts per volt, 4 decimal places

INSTANCE_IREF_WEIGHT

8246.0

internal reference weight, weight decimal point

INSTANCE_JBOX_MV/V1

12342.0

Load cell 1 millivolts per volt, 4 decimal places

INSTANCE_JBOX_MV/V2

16438.0

Load cell 2 millivolts per volt, 4 decimal places

INSTANCE_JBOX_MV/V3

20534.0

Load cell 3 millivolts per volt, 4 decimal places

INSTANCE_JBOX_MV/V4

24630.0

Load cell 4 millivolts per volt, 4 decimal places

INSTANCE_JBOX_REF_WEIGHT

28726.0

reference weight on IT JBOX

INSTANCE_JBOX_WEIGHT1

32822.0

Sensor 1 on JBOX

INSTANCE_JBOX_WEIGHT2

36918.0

Sensor 2 on JBOX

INSTANCE_JBOX_WEIGHT3

41014.0

Sensor 3 on JBOX

INSTANCE_JBOX_WEIGHT4

45110.0

Sensor 4 on JBOX

Integrated Technician Return Values Table

These numbers are floating point equivalent to hex numbers.

NOTE: The Integrated Technician can also be run through the AOP dialog box.

CIP Messages

The weight calibration values can be read and written by CIP messages.

Message Type: CIP generic (Common Industrial Protocol) Service Code: 4C (hex) Class Name: 4 Instance Name: 254 Object Attribute: none, leave this blank

It is possible and convenient to configure the MSG instruction to use the same tag for both source and destination.

●

Chapter 4

There are two read and write calibration commands, each consisting of 6 float values (24 bytes) as follows:

Command (see the list of commands below) Channel (0 or 1) Reserved CalZeroCounts CalLowCounts CalibK

1. Command 1.0: Read calibration values. Use this command to read the rate and

weight calibration values.

2. Command 129.0: Write weight calibration. Use this command to set the 3

weight calibration values: zero counts, low counts, and CalibK (weight per A/D count).

The two commands below read and write configuration data. Each return 52 float values, which are the command, the channel, and the reserved word, followed by 49 parameter values, which are listed in the order of the parameter IDs.

3. Command 15.0: Read configuration data.

4. Command 143.0: Write configuration data.

Note The values written via these commands are NOT saved automatically to the non-volatile

memory and are lost on power down if no save to non-volatile command is given.

There is a command #4 to read the auto preact status values, consisting of 14 REAL values (56 bytes) as follows:

Command #4.0 Channel (0 or 1) Status parameter 55: Average flow rate at end of fill Status parameter 56: Preact A (Fast relay) Status parameter 57: Preact B (Slow relay) Status parameter 58: Flow rate at end of last fill. Status parameter 59: Sampled amount of last fill Status parameter 60: Motion time. Time in seconds after relay close for weight

to come out of motion

Status parameter 61: Fill time. Total time from opening of relays to sampling

weight

Status parameter 62: Velocity stable time. Time after start of fill for flow rate to

become stable.

Status parameter 63: Setpoint A time: time from start of fill to closure of first

relay

Status parameter 64: Setpoint B time: time from start of fill to closure of second

relay

Status parameter 65: Averaged preact value Status Word (bit encoded integer)

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Chapter 5

A load cell must be mounted so that 100% of the load (Vessel w/Contents) passes vertically through the load cell.

Verify that nothing is binding the load cell. This means that nothing is draped across the scale/vessel or the load cell, such as a hose, electrical cord, tubes, or other objects.

Verify that nothing is in contact with the scale/vessel other than service wires and piping that have been properly mounted with flexible connections.

Properly Installed Load Cell

Chapter 5 Calibration

● ● ● ● ●

The Dispenser-Filler Module should be calibrated before use. We also recommend that you verify the calibration periodically or when not in use for extended periods of time. Users and service personnel should be familiar with the procedures in this chapter before installing or operating the Dispenser-Filler Module.

NOTE Do not perform a calibration on either channel while an application is in

operation.

Pre-Calibration Procedures

Verify that the load cells have been properly installed.

Refer to your load cell operations and installation manual for proper installation

instructions.

On some sensors and cells an arrow indicates the direction of the applied load. If

the arrow is pointing in the wrong direction, change the position of the load cell so that it is mounted in the direction of the applied load.

Check for binding on the Load Cell or other parts of the weighing system.

CAUTION: Binding on a scale/vessel or load cell does not allow the load cell free vertical movement

and may prevent the instrument from returning to the original zero reference point.

Electrical Check Procedures

Load Cell/Point Input/Output Measurements

The Dispenser-Filler Module is designed to supply 5 VDC excitation to as many as four 350-Ohm load cells/points per channel. The expected output from each load cell/point will depend on the mV/V rating of the load cell/point and the weight.

●

Chapter 5

A zero reference point will vary from system to system

depending on the “Dead Load” of the vessel. “Dead Load” is

the weight of the vessel and appurtenances only, with no product loaded. In our example we will assume the dead load to be 500 pounds.

The operating range for the scale in this example is 5-10 mVDC with a 500 pound weight range. Note that after zeroing the instrument, the 0 reading refers to the zero reference point and not absolute 0 mVDC or absolute 0 weight.

Millivolts/Weight Scale

For example, a 2mV/V load cell/point will respond with a maximum of 10 mVDC at the load sensor’s full weight capacity, which includes the weight of the vessel and the weight of the product as measured by the load cell/point. Thus, if the load cell/point weight capacity is rated at 1000 pounds, the load cell/point will be 10 mVDC at 1000 pounds,

7.5 mVDC at 750 pounds, 5 mVDC at 500 pounds and so on.

NOTE Load cell/point measurements are checked with a digital volt meter at the J1 connector

on the front of the module or by using INTEGRATED TECHNICIAN with the HI 215IT Junction Box.

Load Check

Place a load (weight) on the scale or vessel, and check to see if the weight reading on the input table changes in the proper direction.

For example: If the input table display reads 100 pounds and a 20-pound weight is placed on the vessel or scale, the ladder logic display should read 120 or some value over 100. With the input table display reading 100 pounds, if a 20-pound load is placed on the vessel or scale and the reading is 80 pounds, the reading is going in the wrong direction and indicates some problem with the system.

If the input table reads improperly or shows no change, something is wrong with the setup. If the input table changes weight in the proper direction, remove the weight and proceed to calibrate the module. Refer to chapter 6 troubleshooting for additional help to determine the cause of the poor weight reading.

AOP Calibration

C2 Calibration

Both C2 and Hard calibrations are available in the AOP dialog box under the Calibration Tab.

C2 calibration requires C2 load sensors. (For scales without C2 load sensors see Hard Calibration below). The Weigh Module reads the performance characteristics of the individual load cells and detects the quantity of load cell(s) in the system. C2 Calibration can be performed by pressing “THE BUTTON” located in the front panel of the module, or via Allen Bradley RS LOGIX 5000 using either the output table or ladder logic.

●

Chapter 5

“THE BUTTON” C2 Calibration

Step 1. Be sure that the parameters have been setup for your weighing process. (See

Chapter 4, Setup)

Step 2. Open the front door of the module.

Step 3. Press and hold “The Button” until the desired Scale LED turns green, and

release, scale led will start flashing.

“THE BUTTON” location on the 1756 nDF

Step 4. Press and release “The Button” again to perform the C2 Calibration. Once the

calibration is completed the Scale LED returns to a steady green.

NOTE: If you do not press THE BUTTON again within 20 seconds, the calibration process times out.

C2 Calibration Using Ladder Logic

Verify that the parameters have been setup for your weighing process in accordance with the setup information provided in Chapter 4.

Step 1. Empty your hopper, if possible. Step 2. Set your cal low reference weight to 0 or if you have product in the hopper use

that as your reference setting. Step 3. Send the C2 calibration command by setting the output table word 0 to the

command number 102.0. Step 4. Monitor your Input table words 0 & 1. Word 0 will echo your command

number when command is complete. Word 1 will be your status, 0 = no errors. Step 5. Calibration complete if no errors NOTE: If you are doing the C2 calibration on channel 2 of a 2 channel module, use

Output table word 8 and Input table words 8 & 9. For ladder logic examples please refer to the http://www.hardysolutions.com website.

Located under the SUPPORT pull down and then select sample programs.

●

Chapter 5

Hard Calibration

Hard Calibration is the traditional method of calibration using test weights. Hardy recommends that the test weights total 80 to 100% of the load capacity.

Step 1. Empty your hopper, if possible. Step 2. Have or set your Cal Low Reference weight to 0, or if you have product in the

hopper use that as your reference setting. Step 3. Send the Cal Low command by setting the Output table word 0 to the command

number 100.0. Step 4. Monitor the Input table word 0 & 1. Word 0 will echo your command number

when command is complete. Word 1 will be your status, 0 = no error. Step 5. Add a known weight to the scale. This should be the same amount of weight as

your Span parameter is set to. Span value is the zero reference weight plus the known amount of weight you will add.

Step 6. With weight on the scale, send the Cal high command by setting the Output table word 0 to the command number 101.0.

Step 7. Monitor the Input table word 0 & 1. Word 0 will echo your command number when command is complete. Word 1 will be your status, 0 = no error.

Calibration is complete if no errors. NOTE: If you are doing the HARD calibration on channel 2 of a 2 channel module, use

Output table word 8 and Input table words 8 & 9.

Hard Calibration Ladder Logic Example

Verify that the parameters have been setup for your weighing process in accordance with the setup information provided in Chapter 4.

For ladder logic examples please refer to the http://www.hardysolutions.com website. Located under the SUPPORT pull down and then select sample programs.

●

Chapter 6

Chapter 6 Troubleshooting

● ● ● ● ●

Chapter 6 provides procedures for troubleshooting the electrical, mechanical and firmware elements of the HI 1756 nDF and for using Hardy’s Integrated Technician (IT®) software utility to isolate problems. Flow charts provide troubleshooting procedures for the dispenser/filler, load cells, and cabling.

Disassembly and Reassembly Notes, Warnings and Cautions

WARNING EXPLOSION HAZARD - DO NOT DISCONNECT EQUIPMENT OR REPLACE

COMPONENTS UNLESS POWER HAS BEEN SWITCHED OFF OR AREA IS KNOWN TO BE NON-HAZARDOUS.

Always replace broken or damaged modules or hardware immediately. Always check to be sure that no loose parts are sitting on printed circuit boards

or electrical connectors or wires when disassembling or reassembling.

Always protect printed circuit boards from electrostatic discharge (ESD).

Always use approved ESD wrist straps and anti-static pads.

Always follow proper safety procedures when working on or around the Rate

Controller.

This chapter describes several tests that can shorten the time for troubleshooting. Most problems require the use of two or more tests to determine the cause.

If a problem is isolated to a load cell, it may not mean the load cell is the damaged component. Mechanical imbalances and system piping stress (lack of piping flexures, pressure hoses draped over, pipes etc.) can make a load cell or weight controller seem to be the problem.

If you are in doubt as to how to resolve a problem or if you need assistance, look for Hardy Process Solutions Web-tech at http://www.hardysolutions.com. Web-tech is updated often and is available 365 days a year 24/7. It contains frequently asked questions to aid you in troubleshooting, and it provides a form for requesting additional information and answers to questions, with no waiting on hold. Located under the SUPPORT pull down, select the online support selection and then WebTech Knowledge base.

Weight and Voltage Testing

This test section looks at the readings from ALL the load cells to test overall system performance and signal voltage readings. This test works for a variety of load cell connection systems.

Further investigation to isolate system problems requires the use of hand tools and multimeters or the Integrated Technician Summing Junction Box and using the IT© Test section.

NOTE IT ®is a registered trademark of Hardy Process Solutions Inc.

Weight

This displays the amount of force seen by all load cells installed in the summing junction box. Further investigation to isolate system problems will require the use of hand tools and Multi-meters or the Integrated Summing Junction box and using the IT test section. This force can show an imbalance or weight distribution problem. Review your system to

●

Chapter 6

Electrical, Mechanical and Configuration reviews

Trad. Cal - A/D Failure Error

Mechanical Inspection

Electrical Inspection

Load Sensor Installation

Drifting or unstable weight readings

Verify individual load sensor operation

insure proper balance. Motors can account for this problem. Piping should not apply any appreciable force on the scale.

mV/V

DC voltage signals are between 0-15 millivolts. Overloads and negative millivolt readings are not shown as actual readings but 15.3 for over voltage and -0.1 for negative voltage. You will need to use a multi-meter with a 200 or 300 mVDC range to view the out-of-range voltages. Millivolt/volt equals the output from a load cell per each volt of excitation. The HI 1756 nDF reads the load cell output in mV/V, which provides higher resolution (4 decimal places) than a milli-Volt reading. This provides more sensitivity to help you troubleshoot the condition of the load cell under certain conditions. Load cells are rated in millivolts/volts. To convert to mV, multiply the mV/V times the sense voltage.

IT Test

If your system has an Integrated Technician Summing Junction box, the IT test can help identify individual load cell problems up to a maximum of four load cell selections.

Sensor Number

Indicates which sensor is under test. Select the target sensor to be tested.

Warning Do not install your HI 215IT summing board in areas susceptible to high vibrations. The

relays on the board can chatter and affect your weight readings and the vibration can crystallize the solder joints.

General Troubleshooting Flow Chart Index

●

Chapter 6

UNSTABLE RATE CONTROLLER

Disconnect external signal cables and

shields

Monitor the reading

for stability

STABLE?

Reconnect signal

cables one at a

time

If installing any cable causes

unstable readings

REVIEW TROUBLESHOOTING

SECTION B: B1.1-B1.7

Go to

Yes

Monitor the

display for stability

Problem could be in

the instrument. Contact

Hardy Customer Support

A1 - Guidelines for Instabilities on Formerly Operating System

●

Chapter 6

Check for

Electrical S tability

OK?

Check for

Mechanical S tability

Yes

OK?

Check Configuration

settings for

stability

Yes

OK?

Yes

Go To

Stability

B - Guidelines for Instabilities on Formerly Operating Systems (Cont’d)

●

Chapter 6

Electrical

B1.1

Physical Grounding -

All common equipment share a common ground point.

Keep the ground cable length to earth ground as short as possible.

Install a new ground rod if the cable length is excessive.

B1.2

Cable -

Cuts or breaks in the load cell insulation allow moisture to wick into the

cable and load points. This can setup stray capacitance charges and allow

ground currents to exist. This could create a highly intermittent situation.

B1.3

Vessel, Fill and discharge piping -

Ground all to a common point to eliminate electrical differences in potential

and static build-up.

B1.4

Load Cells -

Ground straps must be installed to provide a direct discharge path to ground

around the load points.

B1.5

Cable Routing -

Separate high voltage sources and cables from low voltage signal cables.

Stay a minimum of 14 inches from magnetic fields and VFD controls.

Avoid parallel high voltage and signal cable runs.

B1.6

Cable Shielding -

Ground low voltage cable shields only at the controller end.

Grounding both cable ends produce ground currents.

Verify, with and ohm meter, the shield is only grounded at the weight controller.

Disconnect the shield at the controller and check for an open circuit between ground

and shield. Reconnect the shield to ground and confirm a proper ground path from

the IT Junction box to the controller.

Verify the shield is connected at the IT Junction Box.

Load cell shields only

pass thru the IT Junction boxes and are not connected

to ground at that point.

B1.7

Weight Controller - Common AC ground and Chassis grounds.

Go to

B1 - Guidelines for Instabilities on Formerly Operating Systems (Cont’d)

●

Chapter 6

OK?

Yes

OK?

Yes

Vessel When inspecting a vessel, the Center of Gravity (COG)should be low and centered equally over all the load cells.Insure the load is directly over or under the load point to avoid side-loading and

that there isn’t any side loading from piping or external forces.

Install flexures on all piping to insure a free floating vessel. Make sure the vessel and load cell mounts are mechanically stable and fixed. Large changes in individual load cells indicate a shift in the COG or faulty load cells. Piping and motors can effect the individual load cell readings. Allow for a higher reading on load cells that support motors and piping. Insure pneumatic lines are not applying pressure to the vessel when energized. Use check (stay) rods to minimize vessel movement. Make sure the check rods are loose and not interacting with the vessel. Power down all vibration, vacuum and pressurization equipment during the test process.

Configuration Settings Incorrect WAVERSAVER settings can cause unstable weight readings. Adjust to the lowest WS setting that gives you a stable reading. Higher frequencies with low amplitude vibrations - Use WS settings 1 or 2 lower frequencies with high amplitude vibrations - Use WS setting 3 or higher incorrect number of decimal places. Reading weight increments beyond the equipment applications level. (Sed Guideline Calculations below)

Repeatability Divide the total load cell capacity, including decimal points by 10,000. (Expected stable weight reading)

Resolution Divide the total load cell capacity, including decimals points by 30,000. (The amount you can expect to see but not necessarily stable

Return to

STABILITY

B1 - Guidelines for Instabilities on Formerly Operating Systems (Cont’d)

●

Chapter 6

Select

TEST

MV/V

IT TEST Checks

individual load

sensor output

mV/V readings

Select

load

sensor

Record load

sensor mV/V output

level for

comparison

Repeat for all load

sensors

MV/V

readings

acceptable?

Zero mV/V

reading

1) No dead load

Apply load and re-test.

2) Wiring error

Verify color code using the

load cell certificate

3) Open bridge circuit

Disconnect power and verify

load point bridge resistance

reading with an Ohmmeter

1) Stressed load cell, remove

all load and re-test.

2) Excessive loading

For additional

testing go to:

High mV/V

reading

Defective load Cell

Replace and repeat

TEST F

TEST COMPLETE

Yes

High mV/V

reading

F - Verify Individual Load Cell Millivolt Readings

Testing an individual load cell signal output requires an IT Summing Junction box or millivolt meter.

Use the load cell certificate to verify the millivolt per volt (mV/V) rating: Example: 3mV/V load cells produce approximately 15mV at full load. That is 5 volts

excitation x 3 mV/V. At a scale capacity of 1,000 lbs. with 100 lbs. of deadload when empty, the load point mV reading should measure 1.5mV.

●

Chapter 6

The difference between zero and span is less than

1000 counts

Using a millivolt meter, verify that:

• The signal millivolt reading is positive and within the

acceptable range of 0 to 15 mV.

• When weight is applied there is a positive increase

in the signal millivolt readings

• The compression load cell has not been installed

upside down. Refer to the load cell installation guide

for installation instructions.

• No mechanical binding is restricting the vessel

movement during the load

• The load cell wiring is correct

• Each load cell signal changes under load. A single

oad cell installed upside down or wired backwards

can change the total signal output.

SPAN WEIGHT TOO SMALL

• 1000 counts out of 985,000 is very small

• A 100,000 lb scale would require a minimum of 101 lbs

ERROR

PROCEED

WITH

CALIBRATION

Contact Hardy

Instruments

Customer Service

(800) 321-5831

Ext. 5990

Yes

G - Calibration Failed: Not Enough Counts Between ZERO and SPAN

This error only occurs at the SPAN parameter. You may ZERO out straps or chains and other temporary calibration equipment that held

or hoisted test weights. Zeroing the temporary weight does not effect the calibration. To zero out chains or other temporary calibration equipment. Re-run the cal lo routine with an empty scale. The calibration slope will remain, only the zero reference point is adjusted.

●

Chapter 6

1) Keep flexures on the horizontal

2) Vertical flexures should be avoided

3) Do not use fl exures to correct for misaligned piping

4) Do not use hose flexures to make right angle bends

5) Non-flexed piping should have an unsupported horizontal run using a ratio of 36 times it’s diameter

6) Pipe flexure lengths should be a ratio of 6 times it’s dia meter

7) Feed and discharge piping flexed

8) Are the flex joints on the correct side of the valve?

(a) Yo u weigh the output valve, not the input valve (b) Does the weight scale see all the product to be

weighed?

pipe or valve must be included in the weight vessel. (d) Proper position of the flexures are key (e) Yo ur vessel must seem to float.

All pipes and conduits

flexible

Mechanical ly isolated

from ladders and

connecting structures?

1) Floors or structure does not interact

2) Local traffic does not interact

3) Protected from forklifts and adjacent processing equipment.

Are the load cel ls

properly mounted?

1) Level, solid mounting base

2) The load cell is mounted right side up

3) All load cell bolts installed using anti-seize compounds

4) Mechanically aligned to compensate for expansion and contraction

Are check rods

installed to dampen

vessel movement?

1) Protects the load cells from over load and impact forces

2) Limits the movement of the vessel

3) Rods must be loose and not interact with the vessel

Are cables routed

properly?

1) Separate conduit for low and high voltage cables

2) Do not bundle low voltage with high voltage cabl es

3) Maintain at least 3 inches of separation

4) Maintain 14” separation from ma gnetic fields and 440 VAC

5) Cables are in conduit or tied up and protected from damage

Housekeeping

1) Product, tools and production aids are off the vessel.

2) No workers are physically on the scale

3) Must protect equipment from environmental damage

4) Insure openings are sealed to keep water and environmental contaminates from damaging

(a) I nstrument cabi net or enclosure (b) Summing card (c) Load Cells (d) Conduit runs (e) Covers properly installed

Verify Electrical

go to

H - Mechanical Inspection

●

Chapter 6

1) Verify the proper input power, AC or DC, is properly installed

2) Use a meter to verify neutral, ground and hot are correct

Isolated from SCR and motor control circuits

Use a Common earth ground.

(a) Keep ground cable runs as short as possible

(b) Excessive ground cable runs can act as an antenna

for AC noise

static away from the load cell and directly to ground

(d) Install ground straps on the input and discharge

piping and the vessel to a common earth ground

Verify the proper voltage

level has been supplied

Apply power to the

controller only if supply

voltage is correct

1) Verify the front LEDS illuminate

2) Completes the initialization process

3) Reads the weight. This weight value will not be

correct if a calibration procedure was not performed

Does the scale reflect

a weight change?

1) Read the NET weight

2) Send a TARE command to ZERO the NET weight

3) Apply weight to the vessel

DO NOT POWER UP THE CONTROLLER UNTIL

INPUT VOLTAGES CAN BE VERIFIED

(a) Does the weight increase and decrease in the

correct direction with the weight?

(b) Does the weight return to ZERO NET?

calibration is complete

Cabling

1) Use the load cell certificate, manuals or drawings to verify the

load cell color code. Input = Excitation, Output = Signal

2) Shielding

(a) Grounded only at the rate controller

(b) Continuous shield connection from the load cell cable

to the controller. Single point EMI/RFI drain

3) Sense lines installed?

(A) Jumpers or sense lines in the J1 connector?

(B) Sense lines must be installed for C2 calibration

4) Use IT TEST to verify readings

To Verify Proper Load Cell

Operations Go to

J - Electrical Inspection

●

Chapter 6

K - Load Sharing and Load Sensor Checkout

●

Chapter 6

Erratic Flow Rates

This section explains how to resolve problems relating to Flow Rate (FR) and weight calibration.

Flow Rate calculations

1. Verify the scale calibration using test weights. A poor weight calibration will

produce poor rate calculations.

2. Follow the weight troubleshooting flow charts and correct any equipment

binding, rubbing, and piping problems.

3. If the flow rate displayed does not match your test samples:

Re-calibrate the scale Review the troubleshooting tips for mechanical influences relating to the

Look for leaks in the delivery system or refill gate.

4. If the system is slow to change the flow rate (or weight) readings. Adjust the number of averages setting lower. Adjust the WAVERSAVER setting lower.

5. Look for a systematic and consistent change in weight. Determine what a stable

rate should be. If the flow rate displayed on the monitor continuously falls and rises and you never get a stable rate or symmetrical change in weight pattern:

The rate may be too slow for the load cell capacity. The material may be bridging or liquefying and basically inconsistent. The feeder motor may be feeding too fast, mechanisms may be damaged, or

feeder mechanism

working conditions may not be right.

System and Load Cell Tests

Overview of Typical Load Cell System

The typical load cell system consists of one or more load cells/points and an HI 1756 nDF Dispenser-Filler. If you have more than one load point, an optional IT summing junction box can read data for individual load cells.

Load Cell/Sensor/Point - is a strain gauge-based force transducer that generates an electrical signal proportional to the load applied to the scale. Tension or compression type load cells/points can be used to measure pressure, load, or torque.

●

Chapter 6

JUNCTION

BOX

INTERMEDIATE SUPPORT FRAME

FULLY CONSTRAINED

LATERALLY WITH STAY RODS

UNIVERSAL JOINT

HOSE

USE SYMMETRIC BEAM LOADED

THROUGH SHEAR CENTER TO

AVOID TWIST WITH LOAD

NON METALLIC EXPANSION

ASSEMBLY OR HOSE

BIN ACTIVATOR

Controller

The load cell/point uses the 5 volts DC excitation voltage generated by the HI 1756 nDF. It generates a millivolt output proportional to the weight on the scale (0-10mV DC for 2mV/V load cells/points or 0-15mV DC for 3mV/V load cells/points).

The HI 1756 nDF instrument provides among other functions:

Power to the load cell(s)/point(s) Reads the millivolt signal output from the load cell(s)/point(s) Digitizes, interprets, communicates the results in terms of weight and rate

INTEGRATED TECHNICIAN (IT®)

INTEGRATED TECHNICIAN (IT®) is a diagnostics utility that enables the operator to rapidly troubleshoot the individual load cells in a weighing system. IT commands are communicated via the C2 wires connecting the summing card and controller. You must use C2 certified cable, with or without C2 load sensors. Insure the Violet and gray wires are properly installed. An HI 215IT Summing junction box is required to read data for individual load points. It provides separate inputs for up to four load cell.

If you have more than one load cell without the IT junction box, there is no easy way to isolate the load cell signals.

If you have more than one load cell with the IT junction box, the system can provide both the average numerical values and values specific to each load cell. The number for a load sensor is based on the connections in the IT junction box.

Check the installation sequence in the box to determine which load sensor is number 1, 2 and so on. Always install the first load cell in position 1.

If you do not have the optional IT junction box, some of the options described below will not appear on either interface.

●

Chapter 6

Warning Do not install your HI 215IT summing board in areas susceptible to high vibrations. The

relays on the board can chatter and affect your weight readings and the vibration can crystallize the solder joints.

To determine if an instrument or cabling problem exists, verify the basic operation of the system by performing the following system checks.

Stability Test

The Stability test lets you check the A/D Raw count and average. With the IT option, it tests and reports for each load cell. The test sends a fixed signal into the analog-to-digital convertor and calculates the mean squared variation from the average reading, using 100 samples or 150 samples, depending on the Weight Update Rate parameter. The test passes if the mean squared variation is less than 5.0.

If the weighing system passes the stability test, the results show OK and the variation and mean results are posted. FAIL indicates that the Mean Squared Variation is greater than

5.0 so the instrument is considered unstable. In that case, see the Troubleshooting Flow Charts Section.

CAUTION Do not perform the Stability Test during production. The test activities can cause

incorrect readings.

Weight and Voltage Test

The Weight and Voltage tests are used to diagnose a weighing system and, if certain types of problems are indicated, determine their source. It provides the total scale input to the instrument, such as mV/V and Weight in the units selected (i.e. lbs, kg, oz, g).

Running the IT test will show the weight and voltage results for each load sensor, including the following values:

Weight: Weight value recorded on the sensor mV/V: The mV/V reading is sufficient to balance the corners of your scale or vessel. These readings allow you to determine if the problem is in the instrument (internal) or in a load sensor(s) (external). The normal specification range for the Rate Controller is 0-15 mV. Readings outside this range (15.5 mV, 3.1 mV/V Maximum or any negative values), indicate an external problem. (Check for improper wiring).

When you check the results, if all the load sensors read 0.00, something is probably wrong between the HI 1756 nDF and the HI 215IT junction box, e.g., the cable may be disconnected. Something could also be causing the box to not transmit the readings to the HI 1756 nDF.

If you get no reading for one or possibly two or more load sensors (e.g., sensor 3 reads

0.00 or the reading is larger or smaller than it should be) and you know that the sensors are connected to the junction box, either the load sensor is malfunctioning or its cable to the junction box is loose or incorrectly wired.

General Policies and Information

Hardy Process Solutions provides world-wide support for its products. The following paragraphs describe Hardy's customer support services and equipment warranty. When returning a product, call the Technical Service Department listed below for a Return Authorization Number. You will need to provide your company name, address, telephone number, equipment model number, S/N, and a brief description of the problem.

NOTE For all non-warranty repairs a purchase order or credit card information is required.

You can also go to the Hardy web site and request a Return Authorization number. An RA# will be e-mailed to you. http://www.hardysolutions.com/service/repair.php

●

Chapter 6

Warranty

A warranty problem may be handled by returning the product to the factory for repair or replacement under warranty. In the event you experience a problem with this instrument contact your local Hardy Representative or the Hardy Process Solutions Service Center to determine if the problem is covered under warranty.

Web Address: http://www.hardysolutions.com/service/terms.php

Ordering Replacement Parts

Contact the Hardy Process Solutions Sales Department to order replacement parts and option boards. Have your equipment model number and serial number ready. Most parts and components are only available as whole units or major assemblies.

Note System Support (Requires Purchase Order or Credit Card)

Technical Service is provided as follows:

New system start-up: Ensure that the installation is checked and correct;

instruments are calibrated, and operators trained.

Service: Engineers are trained and qualified to provide on-site installation,

calibration, and maintenance.

On-site training: A Hardy Support Representative can be scheduled to train your

operations and maintenance personnel. This can be as simple as basic load cell theory or as complete as troubleshooting techniques which allow you to service your equipment.

For Further Information Contact

Technical Services Hardy Process Solutions, Inc. 9440 Carroll Park Drive, San Diego, CA 92121 Telephone: +1 (858) 278-2900 ext 9550 FAX: +1 (858) 278-6700 Web Site: http://www.hardysolutions.com E-Mail: hardysupport@hardysolutions.com

●

Index

Alarm LEDs, 11 AOP, 12 Applications, 2 Approvals, 6 Auto Zero tolerance, 36 Automatic refill, 3 Averages, 6

Backplane Input Voltage / Current Load / Power Load, 5

C2 calibration, 44 C2 Calibration, 2 C2 Calibration Input, 5 C2 Calibration Output, 5 C2FAILCAPEQ, 29 C2FAILNODEVS, 29 Cable length, 5 Cal low weight, 36 CalibK, 42 Calibration, 43 Calibration Failed, 54 CalLowCounts, 42 CalZeroCounts, 42 Capacity, 37 CE, 6 CIP Messages, 41 Command Return, 29 Common-Mode Rejection, 5 Common-Mode Voltage, 5 Connecting PLC to the HI 1756 nDF, 15 ControlLogix I/O module, 1 CUL, 6 Customer Service, 1

Deinstalling the Module, 8 Digital Volt Meter, 2 Dot matrix display, 12 DVM - Digital Volt Meter, 2

Flow rate filter, 33 Flow rate period, 34 Flow rate time base, 37 Flow rate units, 33

Hard Calibration, 46 HARDCALFAILCOUNTS, 29 HI 215IT JBox Wiring, 10 HI 215IT Series Junction Box, 2 Humidity, 6

I/O Connector, 8 Installation, 7 Integrated Technician, 2, 40, 59 IT JBOX, 40 IT junction box, 59 IT Return Values Table, 41 IT Test, 48

Junction Box, 2 Junction Box Wiring, 10

LEDs, 11 Linking PLC to the HI 1756 nDF, 15 Load Cell, 43 Load Cell Excitation, 5 Load Cell Tests, 58 Load Cell Wiring, 9

Manual Refill, 3 Material, 33 Metric, 32 Mode of Operation, 20 Mode Rejection, 5 Mode Voltage, 5 Motion Tolerance, 36 mV/V readings, 2

Error Codes, 29 Excitation, 5

Filler Control Module, 15

Non-Linearity, 5 NumAverages, 32 Number of Channels, 5

●

Index

Operating Temperature, 6 Overview of Auto-Preact Function, 22 Overview of Flow Rate Control, 17 Overview of Operation, 16 Overview of Relay Operation, 19 Overview of Weight Calculation, 16

pin-out diagram, 8 PLC connection, 15 Preact Value, 20

Refill mode, 33 Relay Mode Considerations, 21 relays, 1 Removing the Module, 8 Resolution, 5 RPI value, 15 RS Logix 5000, 11 RSLinx, 11

sample programs, 45, 46 Span Weight, 36 Stability tests, 60 Start refill weight, 36 Status LEDs, 11

Stop refill weight, 37

Tare weight, 36 Target Weight, 20 Temperature Storage / Operating / Coefficient, 6 Testing

Weight and Voltage, 47

UL, 6 Update Rate, 6 Use of Auto Preact Status Values, 23

Voltage Testing, 47

Waversaver, 2, 6, 33 Weighing System Tests, 3 Weight and Voltage Testing, 47 Weight and Voltage tests, 60 weight calibration, 58 Weight filter, 33 Weight Units, 32 Weight update rate, 33 Wiring Diagrams, 9 WRITEPARAM, 40

Zero tolerance, 36 Zero Track enable, 33

9440 Carroll Park Drive, Suite 150, San Diego, CA 92121

Telephone: 1-800-821-5831 FAX: (858) 278-6700

Web Address: http://www.hardysolutions.com

Hardy Process Solutions Document Number: 0596-0322-01 Revision B

Printed in the U.S.A.

Hardy HI 1756-nDF User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual