4. Features and Functions

4.1. Output Regulation States

The TS Series MagnaDC power supply can operate in either constant voltage or constant current output regulation. The MagnaDC power supply will automatically switch between the two regulation states as a function of the programmed set points and the load impedance. The regulation state is indicated by an illuminated LED above the respective programming knob, also via the external user I/O connector or by computer command.

The TS Series MagnaDC power supply will make a seamless autocrossover from voltage mode control to current mode control, as determined by the voltage and current set points and/or load impedance. If either set point is set to zero, the other set point control will have little or no effect, forcing either a zero voltage limit or zero current limit and preventing output from the MagnaDC power supply.

4.1.1. Constant Voltage

When the constant voltage regulation state is indicated, the MagnaDC power supply is maintaining fixed voltage at the programmed set point, while the output current flucuates as a function of the load impedance, as illustrated by Fig. 4.1.

Fig. 4.1 Operating range in constant voltage mode

To force the TS Series MagnaDC power supply to constant voltage mode, begin with the product in standby and set both voltage and current set points to zero. While pressing the V/I DIS key on the front panel, advance the voltage and current set points for the desired output voltage and the desired crossover current. The crossover current is the maximum desired current, at which the power supply crosses over to current mode control to become a constant current source.

Connect the load and command the power supply to start. The output voltage should be close to the voltage set point. If a load change causes the programmed current set point to be exceeded, the power supply will automatically crossover to constant current output at the programmed current set point and the output voltage will drop proportionately. When setting the current limit, allowance must be made for high peak currents which can cause unwanted crossover.

4.1.2. Constant Current

When the constant current regulation state is indicated, the MagnaDC power supply is maintaining fixed current at the programmed set point, while the output voltage flucuates as a function of the load impedance, as illustrated by Fig. 4.2.

Fig. 4.2 Operating range in constant currnet mode

To force the TS Series MagnaDC power supply to constant current mode, begin with the product in standby and set both voltage and current set points to zero. While pressing the V/I DIS key on the front panel, advance the voltage and current set points for the desired output current and the desired crossover voltage. The crossover voltage is the maximum desired voltage, at which the power supply crosses over to voltage mode control to become a constant voltage source.

Connect the load and command the power supply to start. The output current should be close to the current set point. If a load change causes the programmed voltage set point to be exceeded, the power supply will automatically crossover to constant voltage output at the programmed voltage set point and the output current will drop proportionately.

4.2. Commands

The following commands allow the user to control when the TS Series MagnaDC power supply’s power processing circuitry is engaged and when faults are cleared. These commands are available from the front panel, external user I/O and computer commands. To control which interfaces these commands are available from, the user can control these settings with the following configuration settings:

• INT CTL: Front panel control for Start, Stop, and Clear.

• EXT CTL: External user I/O and computer control for Start, Stop, and Clear.

INT EXT and EXT CTL can both be enabled simulatenously, if desired, for Start, Stop, and Clear control from a variety of interfaces.

Caution

Only disable INT CTL if verified external or computer controls are in place, as it will prevent the user from stopping the product from the front panel.

4.2.1. Start

The Start command engages the power processing circuitry, signaled by a click of the product’s AC input contactor engaging, placing the product in a powered state. The Start command can only be issued when the product is in standby. If the product is either in a alarm state or in a power state, the Start command will have no effect.

After issuing the Start command, the product enters in a soft start, which is a pre-charge circuit used to prevent in-rush current.

Note

For applications demanding fast and/or high repetition cycle times off and on, once in a powered state, it’s recommended to program the product to zero and then back up to the desired set point, instead of using Stop/Start commands. Programming the product down to zero and then back up to the set point eliminates soft start circuitry delay and provides the fastest achievable rise time.

For more information on the Start command:

• Commanding Start from the front panel

• Commanding Start from external user I/O

• Commanding Start from computer command

4.2.2. Stop

The Stop command disengages the power processing circuitry, signaled by a click of the product’s AC input contactor disengaging, placing the product in a standby state. The Stop command can only be issued when the product is in a powered state. If the product is either in an alarm state or in standy state, the Stop command will have no effect.

For safety, the Stop command always takes precedence over any other active command, regardless of the interface. If a Start command is issued while the Stop command is active, the product will not engage.

For more information on the Stop command:

• Commanding Stop from the front panel

• Commanding Stop from external user I/O

• Commanding Stop from computer command

4.2.3. Clear

The Clear command unlatches a fault from memory and transitions the front from an alarm state to standby state. After a fault has occurred, the Clear command must be issued before the product is able to resume operation. Alternatively, the product can be power cycled. The Clear command will only unlatch a fault from memory if the fault condition has been resolved.

For more information on the Clear command:

• Commanding Clear from the front panel

• Commanding Clear from external user I/O

• Commanding Clear from computer command

4.3. Protection and Diagnostics

4.3.1. Over Voltage Trip (OVT)

The TS Series MagnaDC power supply 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 MagnaDC power supply’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 MagnaDC power supply’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 MagnaDC power supply’s maximum voltage rating.

For more information on setting OVT:

• Setting OVT from the front panel

• Setting OVT from external user I/O

• Setting OVT from computer command

4.3.2. Over Current Trip (OCT)

The TS Series MagnaDC power supply 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 MagnaDC power supply’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 MagnaDC power supply’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 MagnaDC power supply’s maximum current rating.

For more information on setting OCT:

• Setting OCT from the front panel

• Setting OCT from external user I/O

• Setting OCT from computer command

4.3.3. Thermal Fault (THL)

The TS Series MagnaDC power supply 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 MagnaDC power supply 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 MagnaDC power supply to cool after a thermal fault occurs, otherwise, the product will enter immediately back into a thermal fault after starting.

4.3.4. Interlock (LOC)

The Interlock feature disables the MagnaDC power supply 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 MagnaDC power supply 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 MagnaDC power supply 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 TS Series MagnaDC power supply 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

• Interlock Set input on the User I/O connection

4.3.5. 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 MagnaDC power supply 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.

4.3.6. Program Line Fault (PGL)

The TS Series MagnaDC power supply 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 MagnaDC power supply.

4.3.7. 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 Fuse Rating.