### Analog Trend with Sample Trigger 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. When the rec input goes from off to on, the TRND input records the current value. Data is not recorded again until the next time the rec input transitions from off to on.
#### 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.
Lock Present Value | Check to output the locked value from the microblock instead of the microblock's calculated value.
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.
Allocate memory for | 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.
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.