High Country Tek HFS-J-Bus User Manual
Page 30
Electronic Controller Solutions for the Global Fluid Power Industry
Hydraulic Fan System Controller with SAE J1939 Interface
HFS-J User Guide
Part No:-
021-00158 Rev C
HFS-J Hydraulic Fan System Controller User Guide
Page | 30
Valve not being driven to maximum:
Note 1:
Ohms Law says that when a coil heats up in use, it increases Ohmic resistance which de-creases the current flow.
Most manufacturers coils, even when hot should still are able to fully shift the valve 100% if their rated voltage is
supplied to them.
In some instances, a voltage slightly greater than the coils rated is needed to maintain the valve 100% position. On a
mobile application, nominal system voltage is quoted as being 12VDC. When the alternator is running, the fully
charged battery voltage should be in the 13.8 – 14.3VDC region. This extra voltage should be sufficient to enable the
valve to drive to 100%.
When an increased supply voltage is not a possible option, you must use a coil rated for less voltage. The controller
will have no trouble driving a 12 V coil from a 24 V supply, or a 10 V coil from a 12 V supply for example.
If the valve shift is erratic
Electrical interference on the control lines can also cause erratic behavior if it is strong enough. Observe the control
inputs on the PC. If noise greater than a few percent is noticed on an unchanging PULSE IN or COMMAND IN input, or
if the digital inputs are toggling, try changing the routing of the control wires to see if the problem changes.
Power supply interference or brown outs can also cause erratic behavior. Observe the power supply on the graph on
the PC. If large dips are noticed, test for a poor supply by running the card off its own fully charged battery.
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