Weigh And Dispense#

Estimated time to read: 21 minutes

In formulation industries, it is very importance that different raw materials are correctly and precisely weighed and placed into appropriate containers. The Weigh and Dispense module helps with this time consuming process, which is sensitive, prone to errors, and involves both manual material handling operations as well as interaction with electronic scales.

The Weigh and Dispense module also ensures full traceability and meets the defined regulatory compliance requirements.

This document will guide you through the Weigh and Dispense process and the necessary system configurations to setup and use the Weigh and Dispense functionality.

Overview#

Weigh and Dispense is a method to provide a controlled, computer-aided process to guide the operator through the weighing and dispense process.

As shown in the figure below, there is a formula that defines the composition of raw materials that are required in certain quantities or proportions to manufacture a certain product. To carry out the Weigh and Dispense process, the operator, following the instructions as provided by the application, picking raw materials of the specified products and then weighing their quantities using an electronic scale until the dispensed quantity falls within the tolerances defined in the formula. Each raw material can be dispensed into the same or different containers and multiple materials of the same product can be used for particular ingredient. After each dispense (partial or complete) the system can print a label that the operator can stick into the dispensed container.

Because the dispensed process may involve dangerous materials and it may require protective equipment, the system will present the operator at all times, the product safety information.

Concepts#

The following table describes the main Weigh and Dispense terms and concepts.

Term / Concept	Description
Electronic Scale	An integrated electronic scale that provides the weight values to the system.
Formula	Defines the list of source products, their required quantities and tolerances. In the application, it's modeled as a BOM of scope Weigh and Dispense.
Gross [Weight]	The total loaded weight of a container.
Hazard Classifications	Product safety classifications according to four dimensions: - Health Hazard (shown in diamond with the blue color) - Fire Hazard (shown in diamond with the red color) - Instability Hazard (shown in diamond with the yellow color) - Specific Hazard (shown in diamond with the white color) The classifications for dimensions health, fire and instability are ranked from zero which represents no hazard until four which represents the most extreme hazard. The specific hazard is a qualitative one.
Hazard Symbols	Additional product hazard classifications (e.g.: Oxidizing, Biohazardous, etc.).
Ingredients	A list of source products required by a certain Weigh and Dispense process.
Negative Weighing	A weighing method where the weigh is determined by the amount that is removed from the source container. The source container is the one that is weighed.
Net [Weight]	The Gross weight minus the tare weight.
Positive Weighing	A weighing method where the weight is determined by the amount that is added to the target container. The target container is the one that is weighed.
Protection Equipment	Different protective equipment (e.g.: goggles, boots, dust mask) that is required to handle material of certain dangerous products.
Raw Material	Same as ingredient - a source material of a certain product used to prepare a certain batch.
Routes of Exposure	A safety indication about the routes of exposure of a certain substance (Inhalation, Skin (or Eye) absorption, Ingestion or Injection).
Safety Data Sheet	A document that contains product safety information.
Tare [Weight]	The weight of an unloaded container.
Target [Batch] Material	A material of a certain product and quantity, for which the raw materials of certain products must be dispensed in the right quantities.
Technical Data Sheet	A document that contains product technical information.

Table: Weigh and Dispense Concepts

Setting Up Weigh and Dispense#

In order to setup Weigh and Dispense it's necessary to follow the steps as described in the table below:

Table: Weigh and Dispense Setup steps

The individual steps are explained in more detail in the sub-sections below.

Create the Necessary Products#

Both the target material Product and source Products are created as regular Products. The safety information is edited as part of the Product as shown in the figure below.

• /Cmf/System/Configuration/Product/SafetyDataSheet/ - for the Safety Data Sheet attachment type

• /Cmf/System/Configuration/Product/Technical/ - for the Technical Data Sheet attachment type

Create a Formula#

A formula is modeled after a BOM object of scope Weigh and Dispense. There are two possible formula types as shown in the following table:

Table: Weigh and Dispense formula types

Furthermore, a BOM of scope Weigh and Dispense can reference a Printable Document of scope Weigh and Dispense Label to define a label that will be printed automatically after each partial or complete dispense. Printable Documents of scope Weigh and Dispense Label cannot have the Applies To defined, and the data contexts as defined in the table below will be created automatically so that they can be referenced in the label.

Table: Weigh and Dispense Label Data Contexts

The two figures below show two examples, using the Absolute formula type and a formula of type Relative.

Create an Electronic Scale#

An electronic scale is a Resource of type Instrument. The important properties for the instrument Resources are the Measurement Units and Calibration Status as shown below:

Manage Instrument Capabilities#

After creating the Instrument, it is possible to add specific characteristics regarding the capabilities of the Instrument. The Manage Instrument Capabilities wizard can be accessed through the Measurement Capabilities section of the Resource details page.

Table: Manage Instrument Capabilities properties

The system will then perform a Precision test in order to select the adequate scales to be used. Using NumberOfDecimalPlaces as the number of decimal places associated with the Precision (for the selected Measurement Capability), with the minimum value being 0, the scales selected will be the ones that obey the rule:

LowerTolerance (rounded up to NumberOfDecimalPlaces) <= UpperTolerance (rounded down to NumberOfDecimalPlaces)

Measurement Capabilities can also be copied from other Instruments, using the 'Copy All Measurement Capabilities' Option, as displayed in the Figure below.

To define the Instrument Mode, the User should access the Change Instrument Mode wizard available in the Resource View, as displayed in the Figure below. The Instrument Modes available are the ones defined as Measurement Capabilities.

Manage Resource Instruments#

To associate an Instrument to a Resource, the User must access the Manage Instruments wizard through the Resource page. The User can either select an Instrument through the search box or through a barcode reader, as displayed in the Figure below. The User can check which are the Instruments attached to a Resource in the Instruments section of the Resource page.

To select an Instrument the following conditions have to be met:

• The Resource must have the Processing Type defined as Process or Line
• The Resource and the Instrument must be in the same Facility
• If the Instrument property Exclusive Usage is set to True, then it can not already be associated with a Resource

Define the BOM Context#

The BOM Context is managed normally, defining the Assembly type as Weigh and Dispense. There are two possible Weigh and Dispense modes as shown below:

Table: Weigh and Dispense assembly modes

An example of a BOM Context for Weigh and Dispense is shown in the figure below:

Manage the Printer Context#

Optionally, edit the PrinterTypePrintersContext Smart Table to specify which printer must be used to print Weigh and Dispense labels for a particular context.

When using Dispense & Continue if you need to print multiple elements of a list, you need to use a Data band. A data source is specified to each Data band providing a table with data fields. It is possible to output a table by placing text components with references to these fields. One data source can specify a previously unknown number of rows with data. The Data band displays as many rows as exist in the specified data source (e.g. if there are 100 rows in the data source, the Data band will show 100 entries). When there is not enough space on one page, a second page will be generated and printing will continue.

Definition for multiple entries:

Result: (two dispenses)

Definition for single entry:

Result: (only the first element of the list will be printed)

Performing Weigh and Dispense#

Once a Material is tracked-in for the setup described in this document, the user can call the Weigh and Dispense wizard. The Weigh and Dispense itself consists of two wizards as shown below:

Preparation#

1. Collect information about the label associated with the BOM by selecting the printer to be used.
2. Display safety information for the Weigh and Dispense process -- the system will merge all the safety information from all the BOM Products and the target Product.

Execution#

1. The execution wizard is used to perform the partial or complete dispenses for the different ingredients.

   

2. In the execution wizard, the user can:

3. Change the printer by pressing the Settings button.
4. Select a different scale by choosing the appropriate value in the weighing panel.
5. Alternate between views (Execution view and Summary view) by pressing the appropriate View button.
6. View Safety Data Sheet and Technical Data Sheets by clicking on the documents icon that also displays the number of documents available.

7. Dispense material by first selecting the source (either by specifying a Material name or a Container name that contains only one Material) and then:

   • Using the positive weighing method pressing Set Tare & Begin
   • Using the negative weighing process pressing Begin Weighing

8. Weigh some quantity and then dispense the material partially or completely.

9. Undo a previous dispense by pressing the Undo button.

10. Stop the current weighing by pressing the Stop button.

Table: Electronic scale status indicator

A timeout can be configured by setting the following configuration entry value: /Cmf/System/Configuration/WeighAndDispense/ScaleTimeOut. The default value is 30 seconds.

Summary#

In any point of the Weigh and Dispense process, the user can have an at-a-glance perspective of the same process by accessing the Summary View in the top left corner.

Weigh and Dispense Quantity Calculations#

The calculation for the required quantities and tolerances vary depending on the formula type (Absolute or Relative).

Minimum Tolerance Calculations#

Calculating the minimum tolerance takes into account the range of the measurement capabilities of the selected instruments and the BOM Items selected. This multi-step process will produce the result of the high level algorithm below:

if (TargetQuantity = Lower Tolerance)
{
    MinimumTolerance = Upper Tolerance - Target Quantity
}
else if (TargetQuantity = UpperTolerance)
{
    MinimumTolerance = Target Quantity - Lower Tolerance
}
else
{
    MinimumTolerance = Minimum (
        Upper Tolerance - Target Quantity,
        Target Quantity - Lower Tolerance
        )
}

Afterwards, the value retrieved for Minimum Tolerance will be divided by the value for Precision quantum (configuration entry /Cmf/System/Configuration/WeighAndDispense/PrecisionQuantum) and we will obtain a final and adjusted Minimum Tolerance.

However, if the test for Precision is not set, the value retrieved for Minimum Tolerance will be:

Adjusted Minimum Tolerance = Minimum Tolerance / (Target Quantity * Accuracy Quantum)

where the value for Accuracy quantum is retrieved from the /Cmf/System/Configuration/WeighAndDispense/AccuracyQuantum configuration entry.

Calculation examples#

To better illustrate the scenario, let's imagine the case where the target material quantity is 100 Kg, the figures below illustrate the quantity calculations for formulas of type Absolute whereas as well as the quantity calculations for formulas of type Relative.

Automatic tolerance calculations in BOM Products#

There is a possibility to perform calculations of the values for Lower Tolerance, Required Quantity and Upper Tolerance when defined in the BOM, through the use of a Rule and an attached DEE Action.

If the current BOM Product has a Quantity Calculation Rule set, after pressing the Begin Weighing button the system must call the defined rule, which will return the values for Lower Tolerance, Required Quantity and Upper Tolerance, expressed in the Units defined by the BOM. A visual notation will be displayed next to the BOM Product currently being weighed. If the rule returns an error, this will be presented to the user and the operation cannot begin. If the rule is successful, the values for Lower Tolerance, Required Quantity and Upper Tolerance will be updated on-screen and the user can proceed with the operation.

Using Weigh and Dispense With A Single BOM Across Multiple Steps#

In some cases, the dispensing of the different ingredients will take place over multiple steps for the same BOM. This is a supported scenario, but it requires some specific handling as described below:

Create a BOM defining the Assembly Step for every BOM Product#

Set the Target Quantity on the Target Material#

Because the formula is intended to be applied to a constant target quantity across multiple steps, the reference quantity that must be used for calculating the quantities to be dispensed in this case cannot be the material primary quantity. Therefore, there are two Material properties that must be defined for the partial Weigh & Dispenses work correctly:

• Target Material Quantity
• Target Material Units

Perform the Partial Weigh and Dispenses#

Perform the partial Weigh and Dispenses. Note that in each Step, the BOM is filtered by the defined Assembly Step.

Remove the Target Quantity#

After all partial Weigh and Dispenses are completed, it's strongly recommended to remove the properties Target Material Quantity and Target Material Units, otherwise there will be several operations restricted for the Material.

Electronic Scale Integration Information#

The Weigh and Dispense GUI makes some assumptions about the electronic scale communication via the application message bus. The message structures are described below.

Instrument Configuration#

Table: Instrument Configuration

{
    "SendToSubject": "CMF.Resource.[ResourceId].[Guid]",
    "SetTare": true / false
}

Begin Weighing#

Table: Begin Weighing

{
    "SendToSubject": "CMF.Resource.[ResourceId].[Guid]",
    "Timeout": 6000,
    "ResetTare": true/false
}

Stop Weighing#

Table: Stop Weighing

{
    "SendToSubject": "CMF.Resource.[ResourceId].[Guid]"
}

Notify Weight Value#

Table: Notify Weight Value

{
    "Timestamp": "2019-02-05T11:17:51.626Z",
    "Value": 1234.5678,
    "IsStable": false,
    "Extra":
        {
            "TareValue": 0,
            "WeightIncludesTare": false,
            "WeighingUnits": "Kg"
        }
}

Interface events#

Table: Interface events

Among the possible events to use this message structure are the following:

• Dispense and Continue
• Dispense and Reset
• Dispense
• Begin weighing
• Complete weighing
• Scale change
• Weighting mode change (positive to negative or vice-versa)
• Undo
• Page close (abrupt)
• Ingredient selection (switching ingredients or W&D page open)

Example 1 (Weighting mode change)#

{
    "OperationType": 10,
    "Data":
    {
        "WeighingMode": "Negative"
    }
}

Example 2 (Ingredient selection)#

{
    "OperationType": 13,
    "Data":
    {
        "tareValue": 0,
        "dispensedQuantity": 0,
        "requiredQuantity": 3,
        "bomProductName": "BomAutomationWD#IG.4ToFlour.6",
        "bomProductId": "2002110227330000006"
    }
}

Example 3 (Generic)#

{
    "OperationType": 6
}

Table: Electronic Scale integration messages

IoT and MES integration flows#