PDP User’s Guide
3/28/2018
Cross The Road Electronics Page 17 3/28/2018
4. Functional Limitations (software)
Functional Limitations describe behavior that deviates from what is documented. Feature
additions and improvements are always possible thanks to the field-upgrade features of the
PDP.
4.1. Firmware <1.40: If Robot Is Enabled/Disabled/Enabled Quickly, FRC
robot may momentarily disable.
When PDP is wired to roboRIO’s CAN bus and robot enters disabled state, roboRIO typically
begins extracting logged records from PDP. However if robot is immediately enabled after
initially entering disable, the roboRIO may very briefly disable as it finishes extracting PDP logs
despite being enabled in the Driver Station.
This occasionally causes motor-drive to briefly disable once after enabling robot. Additionally
the fault count will increment in the Driver Station (lightening tab).
Issue is fixed in PDP Firmware 1.40. When PDP detects roboRIO is enabled it will abort
extraction, therefore preventing the problem condition from occurring.
4.2. Firmware <1.40: Power and Energy
Power and energy signals were not computed correctly in firmware versions earlier than 1.40.
Updating to 1.40 will ensure Power and Energy signals are updated correctly.
4.3. LabVIEW: Energy signal is not scaled to Joules.
The Energy signal in LabVIEW is computed in engineering units where each unit is 0.020
Joules. Multiply the signal value by 0.020 to scale to Joules.
4.4. C++/Java: Energy signal is in Millijoules.
The Energy signal in C++/Java is computed in units where each unit is 0.001 Joules. Multiply
the signal value by 0.001 to scale to Joules. If using this signal for robot-processing, be sure to
check for the fix whenever updating C++/Java libraries.
4.5. Firmware <1.37: Current may read ~2A when there is no current.
The current sense circuitry has biasing (similar to a gyro). Firmware 1.37 and on will zero the
output so that 0A is read when there is no load.
