### Digital Trend The information below provides a FULL description of this microblock and all of its properties. What information you see and what you can do with it depends on your license and the application you are in, and in some cases, a controller's driver version.
Microblock family | Log microblocks
Icon and symbol |
What it does | This microblock records data for trend purposes from microblocks that do not support built-in trending.
#### Properties TIPS Alt+click any value in the WebCTRL® or Field Assistant interface to view property details, including its editing privilege and expression (location path) for use on graphics. You can right-click some properties in the EIKON® Property Editor and select Make editable or Make read-only to determine that property's functionality in your system.
Display Name | The microblock label used in the EIKON® application and the WebCTRL® interface. You can use any characters except the " character.
Reference Name RefName | Use the default reference name unless you want a more descriptive name for graphics or network links. Limitations: lower case only limited to 40 characters cannot begin with a number must be unique within a control program
Description | (optional) A BACnet-visible microblock description.
Editing Privilege | Preset - Each microblock property has an appropriate privilege or role assigned to it. You can use Global Modify in the WebCTRL® interface to find out what the actual privilege is. CAUTION If you change the Editing Privilege from Preset, the privilege you select will be used for all properties of this microblock, which is not always desirable.
Enable Trend Log | Check to have the controller collect trend data for the microblock's present value.
Sample every ___ (hh:mm:ss) | Records the microblock's present value at this interval. EXAMPLE Type `00:10:00` to record the microblock's present value every 10 minutes.
Sample on COV (change of value) | Records the microblock’s present value only when the value changes.
Max samples | The number of data samples the controller allocates memory for. Memory consumption is 10 bytes for each sample plus 48 bytes. For example, for 100 samples: (100 x 10 bytes) + 48 = 1048 bytes of memory The allocated memory is constant regardless of how many samples are actually recorded. If you do not enable trending, no memory is consumed. NOTE Click Reset on the microblock's Properties page in the WebCTRL® or Field Assistant system to delete all samples currently stored in the controller.
Enable Trend Historian | Check this field to archive the controller's collected trend data to the system database after every 129 data samples. NOTES You must check Enable Trend Log if you want to Enable Trend Historian. You can change Enable Trend Historian archival settings and other trend properties on the Properties page in the WebCTRL® or Field Assistant system.
Keep historical trends for __ days | This is based on the date that the sample was read. Set this field to 0 to use the system default value.
Write to historian: Every ___ trend samples Use default (45% of Max samples) | Writes all trend data in the controller to the system database each time the controller collects the specified number of samples. You can select Every __ trend samples and enter a number greater than zero and less than the number in the Max samples field, or you can select Use default. The number of trends specified must be accumulated at least once before the historical trends can be viewed.
Active Text | The Active Text your system displays when the microblock's output is on, or true.
Inactive Text | The Inactive Text your system displays when the microblock's output is off, or false.
In the WebCTRL® or Field Assistant system only: |
Stop When Full | Check this field to stop trend sampling when the maximum number of samples is reached.
Enable trend log at specific times only? | Collects trend data for the specific period of time you define in the time and date fields.
Store Trends Now | Writes all trend data in the controller to the system database without having to enable trend historian.
Trend samples accumulated since last notification | Shows the number of samples stored in the controller since data was last written to the database.
Last Record Written to Historian | Shows the number of trend samples that were last written to the database.
BACnet Configuration | The Object Name is a unique alphanumeric string that defines the BACnet object. Although the Object Name field can be edited, it is not recommended. The Notification Class is set to 1 to receive alarms generated by Automated Logic® controllers.