11. Special channel functions

Fixed

Channel output state and values will remain at the immediate value, i.e. the channel is not affected by the triggering system.

SCPI

CURRent:MODE FIX

VOLTage:MODE FIX

List

Channel output state and values will change according to the defined sequence of output voltages and currents of specified duration (see List programming).

SCPI

CURRent:MODE LIST

VOLTage:MODE LIST

When trigger list is active, channel’s output voltage and current set options will be replaced with the list icon that leads directly to the channel trigger settings page (i.e. the page shown above).

When executing the list, if there is at least one step that lasts 5 or more seconds, an overlay with countdown information will be displayed.

The example shows that a step is being performed on the second channel and that it has 3 hours and 21 minutes left to complete.

Step

Channel output state and values goes to the step level when a trigger occurs.

SCPI

CURRent:MODE STEP

VOLTage:MODE STEP

Voltage:

Programmed new value to which the output voltage will be set when the trigger system is initiated.

When trigger step is active, channel’s output voltage and current set options will be replaced with the step icon that leads directly to the channel trigger settings page (i.e. page shown above).

Overview

The list programming editor makes it easy to set multiple output voltages and currents that will be set in sequence.

A program list can have up to 256 steps with equal or varying duration or time intervals (dwells).

Entering a new or editing an existing value will require a tap on the cell when the numeric keypad will open. A preview of the entered sequences will be displayed at the top of the page.

If the values of voltage and current defined in the list exceed the currently active limits, the list will be interrupted at the first step with too high value. For example, if the output voltage is limited to 10 V, and the list has the following steps: 5, 15, 20, 30 V, the list execution will be interrupted when the 15 V step is reached.

The number of steps in the program list is 256. The list editor displays 5 steps at a time, and when at least one cell in each of first five steps is filled, a navigation arrow will be enabled in the status bar to move to the next five steps.

List import and export

An already defined list can be imported or exported. The storage location is the Lists folder on the SD card.

Selecting the file manager icon will open a menu to export or import the list.

If you import a list, the contents of the Lists folder will be displayed.

While exporting list can overwrite existing list or saved in a new file by choosing New file option.

A programming list can have "symmetric" and "asymmetric" columns. A symmetric column is used when the minimum two different values need to be defined. For example, if a four-step list has a first step of 100 ms and all others of 500 ms, then it will be necessary to enter 100, 500, 500, 500 ms. However, if the output voltage and current in all steps will have the same duration, e.g. 100 ms, then it will only be necessary to enter 100 ms in the first cell and the rest will be able to remain blank.

The picture above shows an example of an incorrectly defined list that has more than one dwell value, but less than the number of defined steps. So, either 500 ms should be deleted in the second row (marked with arrow) or dwell values for the remaining cells should be entered.

Dwell

Dwell is the time that the output will remain at a specific step. Dwell times can be programmed from 0 through 65535 seconds.

If the dwell is set to 0 ms, the firmware will try to spend the shortest possible time in this step, but there is no minimum duration that can be guaranteed (it depends on the current load of the microcontroller).

SCPI

LIST:DWELl {<time>}

Voltage

This column contains the voltage values for each step.

SCPI

LIST:VOLTage {<voltage>}

Current

This column contains the current values for each step.

SCPI

LIST:CURRent {<current>}

List count

Sets the number of times that the list is executed before it is completed. The list count range is 1 through 65535 or it could be set to infinity (∞ sign on the numeric keypad) to execute a list continuously.

SCPI

LIST:COUNt {<count>}

On list stop

Define channels condition when programming list execution is not prematurely stopped (e.g. with ABORt command or by user action).

SCPI

TRIGger:EXIT:CONDition {<condition>}

11.2.1. Inserting a new step

Inserting a new line is possible by selecting the + icon on the status bar when the menu with the options described below will open.

Insert row above

Lets you add a new step above the current cursor position. All values from the step the cursor was on will be copied to a new step.

Insert row below

Lets you add a new step bellow the current cursor position. All values from the step the cursor was on will be copied to a new step.

11.2.2. Deleting of list items

Deleting part or all of the list is possible by selecting the – icon on the status bar when the menu with the options described below will open.

Delete row

Deleting a row at the cursor position. The row must have at least one value entered to be deleted.

Clear column from cursor down

Deleting only the contents of the column from the cursor position down.

YT view value #1

YT view provides a graphical view of two measured output channels at the same time. The selected values are displayed in different colors. By definition, voltage is shown as the first value and current as the second value.

Through this menu, it is possible to set a new value that will be displayed in the color of the first value.

SCPI

INSTrument:DISPlay:TRACe1 {<value>}

Model

Displays module’s model name and version. In the case of a two-channel module, the same model name and version will be displayed for both channels.

SCPI

SYSTem:CHANnel:MODel?

Brand

Module manufacturer name

Pinout

Displays the connection diagram to the module terminals.

11.5. Advanced options

The DCP405 module, in addition to its Hardware OVP, comes with the following advanced features:

• Dual current ranges
• Remote voltage sensing (RSense)
• Remote voltage programming (RProg) and
• Down-programmer (DP)

11.5.1. Current range

Best (default)

The DCP405 module has two current ranges. This option allows the current limit to be set in the best possible resolution. This will automatically activate a lower range for a set current limit of less than or equal to 50 mA, and a higher range for a current limit of more than 50 mA.

If the current range is set to Best, when the channel is in maximized view, an asterisk will be displayed next to the indication of the currently selected current range. In this way, it will be possible to distinguish whether the current range is a result of Best or manual selection.

SCPI

CURRent:RANGe DEF

11.5.2. Remote voltage sensing

The main purpose of the remote (external) sensing function is to ensure that the programmed voltage is accurately delivered to the load in such a way as to cancel the voltage drop caused by the long and thin cables used to connect the load.

Remote sensing needs to connect the power leads from the output terminals to the load and the sense leads from the sense terminals to the load.

Remote sensing cables should be twisted-pair and preferably shielded. When shielded, only one end needs to be connected to an PE potential.

Remote voltage programming allows the output voltage to be set from an external source like signal/function generator. The input sensitivity is 16 V/V so the control voltage should not exceed 2.5 V.

When this mode is set, the firmware will automatically activate the OVP and set it to max. value (40.5 V).

Remote voltage programming will not be possible if the channel is coupled in series or in parallel with another module or tracking mode is active.

SCPI

VOLTage:PROGram EXT

The down-programmer (DP) can be thought of as an internal load across the power module’s output terminals that helps bring the output voltage down quickly.

The primary function of the DP is to discharge the output capacitor but in some cases this feature may be used as a load to the connected device.

The ability to rapidly transition from a higher to a lower constant voltage level also greatly improves the power module’s output response time.

When DP is active its continuous current sinking is limited by firmware to 2 W.

However, it can sink over 2.5 A in short time that is sufficient for rapidly down-programming the output capacitor together with majority of loads connected to the output.

The DP state is relevant only while the channel output is turned on.

SCPI

OUTPut:DPRog {<state>}