Details for DDEntity "143 - Physical Actual Value Time Latency"

143 - Physical Actual Value Time Latency Request changes
DefinitionThe Actual Value Latency Time is the time lapse between the moment this actual value is communicated to the Task Controller, and the moment that this actual value is physically applied on the device. That means if the system needs 2 seconds to calculate or measure a value before communicating it on the network, then the Actual Latency Time value is minus 2 seconds. Depending of the system characteristics the latency time could be negative or positive. In case where the system communicates an actual value before the actual value has been physically applied the latency value should be positive. In case where the system communicates an actual value after the actual value has been physically applied the latency value should be negative.
CommentThe use of this DDE is to inform the overall system (e.g. Dektop Software, Task Controller) how the system works. The TC shall not shift this information into log files nor shall the device do that when sending actual values. Example for a positive value: A seed flow sensor is placed at the start of the seed tube. At the moment the sensor measures seed flow X, it takes Y seconds for this flow to reach the coulters. The measured value is ahead of the physical value of the unit (coulters). So the latency could be plus 2 seconds. Example for a negative value: A flow sensor has a delay in its response to a flow change that means it takes Y seconds to realize the change. At the moment the sensor measures flow X, the flow is already present for Y seconds on the physical unit. The actual value is ahead of measured value. So the latency could be minus 2 seconds.
Typically used by Device Class(es) 2 - Primary Soil Tillage
3 - Secondary Soil Tillage
4 - Planters /Seeders
5 - Fertilizer
6 - Sprayers
7 - Harvesters
8 - Root Harvester
9 - Forage harvester
10 - Irrigation
14 - Special Crops
Unit Symbolms -
Bit Resolution1
SAE SPNnot specified
CANBus Range-2147483648 to 2147483647
Display Range-2147483648 to 2147483647
Submit Date2005-03-01
Submit By11783-Part 10 Task Force
Submit Company89 - Kverneland Group, Electronics Division
Revision Number2
Current StatusISO-Approved
Status Date2011-04-04
Status Comments

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