Protection and Diagnostics

Over Voltage Trip (OVT)

The DBx Module has a programmable Over Voltage Trip setting used to shutdown the product if an undesired maximum voltage value is measured across the DC output. The OVT setting can be adjusted to a maximum of 110% of the specific DBx Module Add-On’s full scale voltage rating. An over-voltage condition must be sustained for ~ 30 ms for the OVT fault to register.

When an OVT fault occurs, a contactor on the AC input opens, providing a mechanical break to the power processing circuits, but leaving the control power in place. An OVT alarm is indicated by red OVT LED illumination on the front panel, +5V on Pin 34 of the external user I/O and by computer command by querying the Questionable Register. To resume operation, the DC output voltage must be drop below the DBx Module Add-On’s OVT setting, the Clear function must be issued, and the input re-energized with the Start function.

The OVT setting can be programmed through the front panel, through 0-10V analog input on Pin 4 of the external user I/O, or programmatically through software.

The factory default OVT setting is 110% of the specific DBx Module Add-On’s maximum voltage rating.

For more information on setting OVT:

Over Current Trip (OCT)

The DBx Module has a programmable Over Current Trip setting used to shutdown the product if an undesired maximum current value is measured across the DC output. The OCT setting can be adjusted to a maximum of 110% of the specific DBx Module Add-On’s full scale current rating. An over current condition must be sustained for ~ 60 ms for the OCT fault to register; this fault is purposely delayed to avoid nuisance trips.

When an OCT fault occurs, a contactor on the AC input opens, providing a mechanical break to the power processing circuits, but leaving the control power in place. An OCT alarm is indicated by red OCT LED illumination on the front panel, +5V on Pin 32 of the external user I/O and by computer command by querying the Questionable Register. To resume operation, the DC output current must be drop below the DBx Module Add-On’s OCT setting, the Clear function must be issued, and the input re-energized with the Start function.

The OCT setting can be programmed through the front panel, through 0-10V analog input on Pin 23 of the external user I/O, or programmatically through software.

The factory default OCT setting is 110% of the specific DBx Module Add-On’s maximum current rating.

For more information on setting OCT:

Thermal Fault (THL)

The DBx Module has internal thermal switches on its various heatsinks to ensure operation at temperatures within the product’s design specifications. A thermal fault typically results from one of the following conditions:

  • Operating in an environment above the maximum ambient temperature specification.

  • Blocking the air intake.

  • Internal fan or solenoid failure.

  • Broken electrical contact to thermal switches.

  • Coolant intake temperatures are above those recommended (water cooled units only).

When a thermal fault occurs, a contactor on the AC input opens, providing a mechanical break to the power processing circuits, but leaving the control power and fan power in place. The user is prevented from enabling the DBx Module Add-On through the front panel, external interface, or computer command. A thermal alarm is indicated by red THL LED illumination on the front panel, +5V on Pin 9 of the external user I/O and by computer command by querying the Questionable Register.

To resume operation, the internal thermal temperature must return to return to safe operating temperatures, the Clear function must be issued, and the input re-energized with the Start function. Allow sufficient time for the DBx Module Add-On to cool after a thermal fault occurs, otherwise, the product will enter immediately back into a thermal fault after starting.

Interlock (LOC)

The Interlock feature disables the DBx Module Add-On by entering a soft fault state. The safety feature is triggered whenever the +5V signal applied to the interlock pin is broken. By default, interlock is disabled when the DBx Module Add-On ships from the factory. Interlock can be enabled from the front panel, computer interface. Once interlock is assigned to one of the pins listed in external user I/O +5V must be present to operate the product. There are two method to providing +5V to the interlock pin:

  • Providing a physical short from the provided external user I/O +5V signal (Pin 26) to the interlock digital input (Pin 37)

  • Using an external user supplied +5V signal with reference to the external user I/O GND signal (Pin 7).

With either method, an external dry contact may be used to trigger the interlock.

When the +5V interlock signal is broken, the dissipative elements are switched out of the DC bus using a high-speed switching device, the DBx Module Add-On is placed in a soft fault state.

To resume normal operation, the +5V signal must first be restored to the interlock input and the Clear command issued.

By factory default, the DBx Module ships with Interlock functionality disabled. For more information on enabling or disabling the interlock feature:

  • Enabling or disabling interlock via the front panel

  • Enabling or disabling interlock via computer command

Phase Loss (PHL)

MagnaDC power supplies monitor that AC input voltages to ensure the rated input voltage is present. In the event that Phase A falls below 10% of the rated input voltage, the product will trip with a phase loss alarm.

When a phase loss occurs while the product is operating, a contactor on the AC input opens, providing a mechanical break to the power processing circuits, but leaving the control power and fan power in place. The user is prevented from enabling the DBx Module Add-On through the front panel, external interface, or computer command. When a phase loss occurs while the product is in standby, the user will also be prevented from enabling the product through the front panel or external interface. A phase loss alarm is indicated by red PHL LED illumination on the front panel or by computer command by querying the Questionable Register.

The product should not be operated with a phase imbalance. When a phase loss alarm occurs, inspect the AC input connections to ensure secure connections. Investiage the AC power system and monitor the bus voltage to ensure it is providing a steady line-to-line voltage in accordance with the power supply’s rated AC input voltage requirements.

To resume operation, the AC line voltage must return to within 10% of the product’s nominal AC input voltage requirement, the Clear function must be issued, and the input re-energized with the Start function.

Program Line Fault (PGL)

The DBx Module monitors the 0-10V analog programming inputs on the external user I/O connector for erroneous input. In the event that any applied analog input voltage is greater than 12.5 V, a contactor on the AC input opens, providing a mechanical break to the power processing circuits, but leaving the control power in place. An PGL alarm is indicated by red PGL LED illumination on the front panel, +5V on Pin 27 of the external user I/O and by computer command by querying the Questionable Register.

To resume operation, the analog input voltages must return to return to under 12.5 Vdc, the Clear function must be issued, and the input re-energized with the Start function. Investiage the source of the erroneous analog input voltage to prevent possible damage.

Caution

Analog input programming voltages in excess of 20 Vdc will damage integrated circuits on the control board and require control board replacement. Always verify analog input signals with an external voltmeter before connecting them to the DBx Module Add-On.

Fuse (FSE)

MagnaDC power supplies contain a variety of power and control fuses. An fuse alarm is indicated by red FSE LED illumination on the front panel, +5V on Pin 15 of the external user I/O and by computer command by querying the Questionable Register. The fuse alarm indicates that one of the three main fuses has cleared.

Note

MT Series Products Only. For the power processing circuitry, MT Series programmable DC power supplies are equipped with a 3-phase AC breaker instead of fuses. In the event the breaker is tripped or if the breaker is not engaged after applying turning on control power via the front panel control power switch, the FSE alarm will indicate. After engaging the breaker to the on position, the procedures to the clear the FSE alarm are as noted below.

To resume operation, the fuse must be replaced, the Clear function must be issued, and the input re-energized with the Start function.

For more details on fuse ratings and replacement, see installation-input-fuse.