> ## Documentation Index > Fetch the complete documentation index at: https://documentation.kodelabs.com/llms.txt > Use this file to discover all available pages before exploring further. # Workflow logic blocks > Reference guide for all logic block types available in the FTT workflow builder, including read, write, parameter, arithmetic, conditional, timing, and testing blocks. Logic blocks are the building components of FTT workflows. Each block performs a specific operation. You connect blocks on the canvas to create the testing logic for your equipment. This page is a block-type reference. For how a finished workflow decides pass or fail, see [What is Functional Testing?](/products/ftt/overview). For end-to-end custom authoring, see the [Workflow creator guide](/products/ftt/workflow-creator-guide). Most sites start with the [workflow library](/products/ftt/fcu-workflows) before they edit blocks. ## Write blocks Write blocks issue commands (overrides) to device points. Each write block activates as soon as data flows into its trigger input. The trigger accepts number, boolean, or string data observations. Use write blocks to command equipment during test sequences, such as closing a damper or turning on a fan. ### Command actions and priority levels Cloud BMS uses a BACnet-inspired priority model for writable points. The same command dialog appears for BACnet and non-BACnet integrations, such as REST API thermostats. How each action maps on the device depends on the connector. BACnet points that accept commands have **16 priority levels** (1 is highest, 16 is lowest). When every level is empty (`null`), the point uses a **fallback / default** value (`Relinquish_Default` in BACnet). That fallback is **not** a 17th BACnet priority. Some interfaces label it as level 17 for display only. `Override` and `Set` turn different knobs under the hood, even when the visible value looks the same. | Action | What it writes\* | Description | | ---------- | -------------------- | ------------------------------------------------------------------------------------------- | | `Override` | Priority 8\* | Temporary exception in the priority array. Takes precedence over lower-priority automation. | | `Set` | Fallback / default\* | Changes the fallback or default value. | | `Auto` | — | Clears an `Override` | | `Release` | — | Clears a `Set` | \*Typical for most BACnet and Niagara deployments. Connectors and site standards can differ. `Override`, `Auto`, and `Set` borrow Niagara-style action names. `Release` is a Cloud BMS action that clears a `Set`. In Niagara-style control, `Set` keeps a non-null fallback so sequences and logic keep a reliable baseline. Use the priority array (including `Override`) for programmed automation and temporary exceptions. To make `Set` write to priority 16 instead of the fallback or default, enable **`Set in Slot16`** (Niagara) on the point. Configure that option from [device details](/products/kode-os/devices/devices#view-and-edit-points), [device templates](/products/kode-os/devices/device-templates), or [points batch update](/products/kode-os/points/points-batch-update). Every write block has the following fields: A familiar name for easy reference and reporting. Opens a dialog to select the point you want to write to. The point must meet the block's type requirements. The value to write, specified as a parameter or a static value. Each write block produces a single **Output** that returns a true/false value indicating whether the point was written to successfully. ### Write block types Writes a string value to a point. Specify the value using a parameter or a static string. String Write logic block showing trigger input, name field, field selector, write value input, and boolean output Writes a numeric value to a point. Specify the value using a parameter or a static number. Number Write logic block showing trigger input, name field, field selector, numeric input, and boolean output Writes a true or false value to a point. Specify the value using a parameter or a static "true" or "false". Boolean Write logic block showing trigger input, name field, field selector, boolean input, and boolean output Writes a list of strings to a point. Specify the value using a parameter or a static list of strings. Enum Write logic block showing trigger input, name field, field selector, enum list input, and boolean output ## Read blocks Read blocks bring point data from connected devices into the workflow. Each read block provides two outputs: **Status** (the point's connection status) and **Value** (the current reading from the point). Every read block has the following fields: A free-form input for identifying the block. Use a name that matches the point name for easy reference when troubleshooting or reviewing the workflow. Designates whether this block is the main reference point or a supporting point. Every workflow must have one and only one `Main` point. When an event is generated, the main point serves as the reference to other modules within Cloud BMS. All other read blocks are set to `Secondary`. Select inside the `Field` input to open a dialog where you can browse and choose the target point. Available points are scoped based on the entities defined in the workflow. If you do not see a point you need, verify that the selected entities contain that field. ### Read block types Reads the current string value from a point. String Point logic block showing name field, Main or Secondary toggle, field selector, status output, and string value output Reads the current numeric value from a point. Number Point logic block showing name field, Main or Secondary toggle, field selector, status output, and number value output Reads the current boolean value from a point. Boolean Point logic block showing name field, Main or Secondary toggle, field selector, status output, and boolean value output Reads the current enum-mapped values from a point. The Field selector derives from device entities and enum mapping. Enum Point logic block showing name field, Main or Secondary toggle, field selector, status output, and enum value output ### Read arrays Use Read Array blocks when a device has two or more distinct fields with the same name. Within a device, it is possible to have two distinct points that share the same name, appended with an identifying number. The system identifies their array potential and allows you to select that type. For example, if a device has two compressor stages, determining whether a compressor is running requires checking both points. With a Read Array block, you bring in a single block instead of two separate read blocks. This simplifies the workflow and eliminates the need to cover all variations of multi-stage compressors within a single routine. Each Read Array block has the following fields: A familiar name for the set of points, used for reference and reporting. Select the set of points to read from. Points are derived from device entities and templating multiple points to the same field. Each Read Array block outputs two lists: **Status** (one status per point in the array) and **Value** (one value per point in the array). Reads a list of string values from multiple points mapped to the same field. String Array logic block showing name field, field selector, status array output, and string value array output Reads a list of numeric values from multiple points mapped to the same field. Number Array logic block showing name field, field selector, status array output, and number value array output Reads a list of boolean values from multiple points mapped to the same field. Boolean Array logic block showing name field, field selector, status array output, and boolean value array output Reads a list of enum values from multiple points mapped to the same field. Enum Array logic block showing name field, field selector, status array output, and enum value array output ## Parameter blocks Parameter blocks provide a way to customize values for projects that use the workflow, without editing the workflow itself. The values you set in parameter blocks become available when configuring a job that uses the workflow. Users can override defaults during project setup. Every parameter block has the following fields: A human-readable label for the parameter. Use a descriptive name that can be understood by anyone, such as "Pressure Min Threshold" or "Cooling - Delta." Clear naming minimizes confusion when accessed later to troubleshoot or understand the intent. A string input that appears when the information icon is hovered over during parameter configuration. Use as many words as necessary to communicate the intent of the parameter, its expected range, and any constraints. The default value for the parameter. When you edit parameters during job setup, you alter this input to the algorithm. Users can override this value when setting up an FTT project. The block outputs the value specified in the `Value` field (or the user's override) for use by downstream blocks. ### Parameter block types Outputs a string value. Specify the string to output from this block. Values are available for customization during configuration. String parameter logic block showing name field, hint field, value field, and output Outputs a number value. Specify the number to output from this block. Values are available for customization during configuration. Number parameter logic block showing name field, hint field, numeric value field, and output Outputs a boolean value. Specify the boolean to output from this block. Values are available for customization during configuration. Boolean parameter logic block showing name field, hint field, boolean value field, and output ### Hint tooltip The `Hint` text appears as an information bubble next to the value field when a user configures the parameter during project setup. Parameter hint tooltip showing descriptive text for Pressure Min Threshold during project configuration ## Arithmetical blocks Arithmetical blocks perform mathematical operations on number inputs. Use these blocks to calculate thresholds, derive values, and process sensor data. Multi-input blocks (Difference, Max, Mean, Min) accept two or more inputs. Click the **+** button on the block to add additional input fields. Each input accepts a linked number output from another block or a static value set directly in the field. The block outputs a single **Result** value. Single-input blocks (Absolute) accept one input and output a single **Result** value. Calculates the difference between input values. Outputs the post-calculated value. Use the **+** button to add more operands. Difference arithmetic block showing two numeric inputs, add operands button, and result output Returns the largest value from all inputs. Use the **+** button to add more inputs. Max arithmetic block showing two numeric inputs, add inputs button, and result output Returns the average of all input values. Use the **+** button to add more inputs. Mean arithmetic block showing two numeric inputs, add inputs button, and result output Returns the smallest value from all inputs. Use the **+** button to add more inputs. Min arithmetic block showing two numeric inputs, add inputs button, and result output Returns the non-negative value of the input. Accepts a single number input or a static value. Absolute arithmetic block showing single numeric input and result output Adds all input values together. Use the **+** button to add more operands. Sum arithmetic block showing two numeric inputs, add operands button, and result output Multiplies all input values together. Use the **+** button to add more operands. Product arithmetic block showing two numeric inputs, add operands button, and result output Divides the first input by the second. Use the **+** button to add more operands for chained division. Quotient arithmetic block showing two numeric inputs, add operands button, and result output Returns the remainder from dividing the first input by the second. Modulo arithmetic block showing two numeric inputs and result output ## Array operation blocks Array operation blocks process a list of values collected from Read Array blocks or Buffer blocks. Each block accepts a list input and outputs a single result value. Use these blocks to analyze trends and compute statistics. Returns the difference between the minimum and maximum values in the list. Delta array operation block showing list input and result output Returns the largest number in the list. Max Array operation block showing list input and result output Returns the count of items in the provided list. Accepts lists of numbers, booleans, or strings. Length array operation block showing list input and result output Returns the mean of the numbers in the list. Choose between a weighted mean or a simple average. Mean Array operation block showing weighted toggle, list input, and result output Returns the smallest number in the list. Min Array operation block showing list input and result output Returns the input list sorted in ascending or descending order. Sort Array operation block showing sort order toggle, list input, and sorted list output Returns the standard deviation of the numbers in the list. Choose between a weighted or simple standard deviation. Std Deviation operation block showing weighted toggle, list input, and result output Returns the sum of all numbers in the list. Sum Array operation block showing list input and result output Returns the variance of the numbers in the list. Choose between a weighted or simple variance. Variance operation block showing weighted toggle, list input, and result output ### Example workflows **Difference between highest and lowest values over five minutes:** Read Number > Buffer Time (5 min) > Array Sort (Ascending) > Array Delta **15-minute rolling average:** Read Number > Buffer Time (15 min) > Array Mean ## Conditional and switch blocks Conditional and switch blocks direct the workflow's execution path based on input data. ### If block The If block evaluates a true or false condition and routes data to one of two outputs. Link a block that outputs a boolean to the input. The block routes to `Do` when the condition evaluates to true and to `Else` when it evaluates to false. If conditional block showing boolean input, Do output for true condition, and Else output for false condition ### Switch blocks Switch blocks evaluate a boolean conditional input and return a value based on the result. The top return value outputs when the condition is true, and the bottom return value outputs when the condition is false. You can use block inputs or static values. Outputs the corresponding string associated to the evaluated true or false condition. String Switch block showing conditional boolean input, two string return values, and result output Outputs the corresponding number associated to the evaluated true or false condition. Numeric Switch block showing conditional boolean input, two number return values, and result output Outputs the boolean associated to the evaluated true or false condition. Boolean Switch block showing conditional boolean input, two boolean return values, and result output ### Gate blocks Gate blocks control the flow of data through the workflow by acting as barriers that open or close based on a trigger. Prevents data from passing through until a data observation arrives at the trigger. The trigger accepts number, boolean, or string data. When an input is linked, an output of the same data type appears on the right. Skip Until gate block showing trigger input and data input with matching output Passes data through until a data observation arrives via the trigger, then stops. The trigger accepts number, boolean, or string data. When an input is linked, an output of the same data type appears on the right. Take Until gate block showing trigger input and data input with matching output ## Logical and comparison blocks ### Logical blocks Logical blocks evaluate boolean inputs and produce a boolean result. Use the **+** button to add more operands. Returns true only when all input values are true. And logical block showing two boolean inputs, add operands button, and boolean result output Returns true if any input value is true. Or logical block showing two boolean inputs, add operands button, and boolean result output ### Not block The Not block inverts a single boolean input value. True becomes false, and false becomes true. Not logical block showing single boolean input and inverted boolean result output ### Merge block The Merge block combines multiple inputs of the same data type (number, boolean, or string) into a single output. As a data observation is received from any of the inputs, it is sent to the output regardless of order. Use the **+** button to add more inputs. Merge block showing two inputs of the same type, add inputs button, and single output ### Comparison blocks Comparison blocks evaluate two values and output a boolean result. You can use linked inputs or static values. Outputs true if both inputs are evaluated as equal. Accepts number, boolean, or string operands (both must be the same type). Equals comparison block showing left operand, right operand, and boolean result output Outputs true if the left operand is greater than the right operand. Greater Than comparison block showing two number inputs and boolean result output Outputs true if the left operand is less than the right operand. Less Than comparison block showing two number inputs and boolean result output Outputs true if all items in the input list match the specified value. Link a list containing items of the same type as the value. All comparison block showing list input, value input, and boolean result output Outputs true if the data observation received by the value input is found as an item in the input list. In comparison block showing list input, value input, and boolean result output ## Timing and buffering blocks ### Timing blocks * **Delay On**: requires a condition to remain true for a specified duration before passing it forward * **Delay Off**: requires a condition to remain false for a specified duration before closing * **Timer**: measures how long a condition has been in a specific state ### Audit and Debounce blocks Waits for a specified amount of time and outputs the last value received from the input. Configure the wait time unit (seconds, minutes, or hours) and the count of time units to wait. Audit timing block showing wait time dropdown, static number value, data input, and matching type output Waits for a specified amount of time and outputs a value only if that value has been unchanged during that period. Configure the wait time unit (seconds, minutes, or hours) and the count of time units to wait. Debounce timing block showing wait time dropdown, static number value, data input, and matching type output ### Buffer blocks Buffer blocks collect values from an input into a list. The list is returned when the configured condition (time or count) is met. Collects values from the input into a list that is returned after the specified amount of time. Configure the time unit (seconds, minutes, or hours) and the duration. Buffer Time block showing time unit dropdown, static number value, data input, and list output Collects values from the input into a list that is returned when the count is satisfied. Specify the number of values to collect. Buffer Count block showing count setting, data input, and list output ## Testing blocks (FTT) FTT-specific blocks manage the testing sequence lifecycle. These blocks handle sequence scoring, pass/fail evaluation, stabilization periods, and the release of equipment overrides at test completion. Activates as soon as a data observation goes into its trigger. Outputs a true/false value indicating whether the sequence was successful. Configure the sequence name and count. Sequence testing block showing trigger, name field, sequence count, boolean input, and success output Sends a string value to the workflow logger for debugging and reporting. Link a string output or enter a static string value. Logger testing block showing string input and static value option Initiates when a data observation goes into its trigger. The trigger accepts number, boolean, or string data. Use this block to archive data at specific points in the test sequence. Archive testing block showing trigger input accepting number, boolean, or string data Initiates when a data observation goes into its trigger. The trigger accepts number, boolean, or string data. Use this block to interrupt the test sequence. Interrupt testing block showing trigger input accepting number, boolean, or string data Initiates when a data observation goes into its trigger. The trigger accepts number, boolean, or string data. When the Release block executes, the test ends and all commands issued to the equipment during the test are released. Release testing block showing trigger input accepting number, boolean, or string data Every FTT workflow must end with a Release block. When the Release block executes, the test ends and all commands issued to the equipment during the test are released. ## Time control parameters Most workflows use three standard time control parameters applied to each sequence: | Parameter | Description | Units | | ----------------------- | ----------------------------------------------------------------------------------------- | ------- | | `Min Sequence Duration` | Minimum time the equipment has to respond to a command before evaluation begins | Seconds | | `Max Sequence Duration` | Maximum time allowed for the equipment to meet success criteria before the sequence fails | Seconds | | `Stabilization Time` | Buffer time between sequences to allow the equipment to return to a neutral state | Seconds | ## Next steps Create, test, and manage workflows using the logic builder and debugger. Follow the end-to-end process for designing and building custom workflows. Review how library workflows decide pass or fail before you edit blocks.