SPECIAL SETTINGS
All of the current VEGA PULS 65 radar units used on Heatec AC tanks have special factory settings. These settings can only be made using a computer loaded with special Vega software and a special connect cable. These settings cannot be made using the keys on the PLICSCOM module.
One of the special settings is known as SECURITY. Prior to September 2004 it was set to ON. The advantage of having this setting turned on, is that the unit provides better control of tank overflow.
However, having this setting activated can create a problem in an environment where there is condensation of moisture and vapors. If condensation accumulates on the radar antenna it can keep the radar unit from working properly. This may occur inside an asphalt tank.
Accordingly, radar units used on Heatec AC tanks starting September 2004 have the SECURITY setting set to OFF. This should eliminate possible problems due to condensation.
If your Heatec tank uses the current radar unit that has settings made prior to September 2004 and you think you may be experiencing problems due to condensation, please contact the Heatec service department.
NOTE: The Vega software is designed primarily for use by original equipment manufacturers (OEMs) such as Heatec. It is not recommended for end users.
OVERFLOW PROTECTION
Turning off the SECURITY setting does not leave the radar without overflow protection. However, it could make the radar overflow control more susceptible to problems if the radar antenna is accidentally immersed in asphalt.
In any case, a backup system will prevent overflow if the radar is not working properly. The backup system consists of a proximity switch activated by a float (Figure. 5 and 6). The proximity switch will shut off the unloading pump when filling the tank and the float activates the proximity switch. An indicator light labeled HIGH ASPHALT FLOAT LEVEL (at the unloading pump controls) comes on when the proximity switch has been activated. For more information on shutoff controls please refer to Heatec Tec-Note 9-04-147 Heatec asphalt tanks-maintenance.
In normal operation the radar shuts off the unloading pump before the proximity switch is activated. Thus, if the proximity switch shuts off the unloading pump it means that the radar is not working properly.
So every time you fill the tank pay special attention to whether the indicator light for high float level comes on. If it does come on, this indicates that the radar failed to shutoff the unloading pump and the shutoff was achieved only by the backup system.
If the radar fails to shut off the unloading pump the most likely cause is that the radar antenna was accidentally immersed in asphalt. This should not happen in normal opearation. Cleaning the radar antenna should restore the radar unit to normal operation.
In the unlikely event that both the radar and proximity switch fails to shut off the unloading pump, the asphalt level will reach the top of the vent/overflow pipe inside the tank. It will then spill into the pipe, which will carry it out of the tank onto the ground at the bottom of the tank. Moreover, if an overflow occurs, you can be sure that the asphalt level was high enough to immerse the radar antenna.
RESERVED SPACE
Some space in the top of the tank is reserved to allow for expansion of asphalt and for overflow control when filling the tank. So you should not expect to fill the entire space inside a tank with asphalt. Your volume of asphalt will always be somewhat less than the volume of the tank.
The new settings shown in Figure 4 cause the radar to shut off the unloading pump when the liquid reaches a level approximately 18-5/8 inches below the bottom surface of the upper bulkhead inside the tank. At this level the asphalt will be 38-1/8 inches from the bottom surface of the flange of the radar unit. This is the surface from which all radar measurements are made.
The proximity switch and float system is set up to shut off the unloading pump when the level of asphalt is approximately 7-1/8 inches from the bottom surface of the upper bulkhead
OLDER TANKS
Certain dimensions on vertical tanks manufactured prior to 2001 may differ from those on tanks manufactured after that year. If a radar unit is being retrofitted to a vertical tank manufactured prior to 2001 you may need to use different radar settings than those shown in Figure 4. Otherwise the level indications may be incorrect. Please contact Heatec service department for help.
TECHNICAL SUPPORT
For questions about sensor settings for Heatec tanks, please contact the Heatec service dept, phone 423-821-5200. Please have the model of your sensor. If your sensor was installed at the Heatec factory, please have the Heatec job number. If you need a manual for the VEGA PULS 65 PLICSCOM sensor you can download one from heatec.com/literature/Tec-Notes/actank_pubs.htm.
For problems with the sensor, please contact Ohmart/Vega Customer Support at 1-800-367-5383 or 1-800-543-8668. Please have sensor model. Before calling, please verify that your settings match those shown in Figure 4.
Figure 5. High-level proximity switch and float pipe protruding through sleeve in top of tank.
Figure 6. Float for high-level proximity switch.