Kepco BOP GL Power Supply¶

The Kepco BOP GL power supplies are programmable power supplies that operate in current or voltage mode. The current implementation supports the Kepco BOP 50-20GL model.

Using EPICS Kepco BOP GL power supply module¶

Usage of Python class for EPICS Kepco BOP GL power supplies.

class py4syn.epics.KepcoBOPClass.KepcoBOP(pvName, mnemonic)[source]¶

Class to control Kepco BOP GL power supplies via EPICS.

Examples

>>> from py4syn.epics.KepcoBOPClass import KepcoBOP
>>>
>>> def configurePower(pv="", name="", voltage=5.0, currentLimit=1.0):
...    bop = KepcoBOP(pv, name)
...    bop.reset()
...    bop.setCurrentLimits(currentLimit, currentLimit)
...    bop.setVoltage(voltage)
...    return bop
...
>>> def smoothVoltageTransition(bop, initial=0.0, final=12.0, duration=2.0):
...    bop.setRampWaveform(duration, final-initial, (initial+final)/2)
...    bop.waveformStart()
...    bop.waveformWait()
...
>>> def noiseCurrent(bop):
...    bop.reset()
...    bop.setMode(KepcoBOP.MODE_CURRENT)
...    bop.setVoltageLimits(20, 20)
...    points = [random.uniform(-5, 5) for i in range(100)]
...    bop.clearWaveform()
...    bop.addWaveformPoints(points, [0.025])
...    bop.waveformStart()
...

Constructor See py4syn.epics.StandardDevice

Parameters:	pvName : string Power supply base naming of the PV (Process Variable) mnemonic : string Power supply mnemonic

addLevelWaveform(length, offset)[source]¶

Adds a fixed level wave to the waveform program. This is one of the ways that the device can be programmed to generate a complex waveform. The other way is sending the complete array of points for the waveform. This method is limited to a specific waveform type, but it’s faster to program than uploading individual points. When the final desired waveform can be composed of simple waveform segments, this is the best way to program the device.

Adding points does not execute the program. The method waveformStart() must be called.

Note

When changing operating mode, the waveform program must be cleared if necessary, because the device will prohibit mixing points from different modes.

Parameters:	length : float The duration of the level waveform. The allowed range is 500µs to 5s. The number of points used is 60. offset : float The level offset. The offset cannot exceed the configured device limits.

addRampWaveform(length, height, offset)[source]¶

Adds a ramp wave to the waveform program. This is one of the ways that the device can be programmed to generate a complex waveform. The other way is sending the complete array of points for the waveform. This method is limited to a specific waveform type and it also consumes a lot of points, but it’s faster to program than uploading individual points. When the final desired waveform can be composed of simple waveform segments, this is the best way to program the device.

Adding points does not execute the program. The method waveformStart() must be called.

Note

When changing operating mode, the waveform program must be cleared if necessary, because the device will prohibit mixing points from different modes.

Parameters:

length : float: The ramp length. The allowed range is [1/532, 100] (1.88ms to 100s). The number of points used vary from 20, for smaller ramps, to 3840, for larger ramps.
height : float: The ramp height. The height can be positive or negative. It cannot exceed the range defined by the configured operating device limits.
offset : float: The offset of the ramp middle height. The offset cannot exceed the configured device limits.

addSineWaveform(frequency, amplitude, offset, start=0, stop=360)[source]¶

Adds a sine wave to the waveform program. This is one of the ways that the device can be programmed to generate a complex waveform. The other way is sending the complete array of points for the waveform. This method is limited to a specific waveform type and it also consumes a lot of points, but it’s faster to program than uploading individual points. When the final desired waveform can be composed of simple waveform segments, this is the best way to program the device.

Adding points does not execute the program. The method waveformStart() must be called.

Note

When changing operating mode, the waveform program must be cleared if necessary, because the device will prohibit mixing points from different modes.

Parameters:

frequency : float: The sine wave frequency. The allowed range is 0.01Hz to 443Hz. The number of points used vary from 3840, for lower frequency waves to 24, for higher frequency waves.
amplitude : float: The sine wave peak to peak amplitude. The peak to peak amplitude cannot exceed the range defined by the configured operating device limits.
offset : float: The offset of the sine wave zero amplitude. The offset cannot exceed the configured device limits.
start : float: The starting angle for the sine wave, in degrees. Allowed range is [0.0, 359.99]
stop : float: The stop angle for the sine wave, in degrees. Allowed range is [0.01, 360.0]

addSquareWaveform(frequency, amplitude, offset)[source]¶

Adds a square wave (constant 50% duty cycle, starts with positive excursion) to the waveform program. This is one of the ways that the device can be programmed to generate a complex waveform. The other way is sending the complete array of points for the waveform. This method is limited to a specific waveform type and it also consumes a lot of points, but it’s faster to program than uploading individual points. When the final desired waveform can be composed of simple waveform segments, this is the best way to program the device.

Adding points does not execute the program. The method waveformStart() must be called.

Note

When changing operating mode, the waveform program must be cleared if necessary, because the device will prohibit mixing points from different modes.

Parameters:

frequency : float: The square wave frequency. The allowed range is 0.02Hz to 1000Hz. The number of points used vary from 3840, for lower frequency waves to 10, for higher frequency waves.
amplitude : float: The square wave peak to peak amplitude. The peak to peak amplitude cannot exceed the range defined by the configured operating device limits.
offset : float: The offset of the square wave zero amplitude. The offset cannot exceed the configured device limits.

addTriangleWaveform(frequency, amplitude, offset, start=0, stop=360)[source]¶

Adds a triangle wave to the waveform program. This is one of the ways that the device can be programmed to generate a complex waveform. The other way is sending the complete array of points for the waveform. This method is limited to a specific waveform type and it also consumes a lot of points, but it’s faster to program than uploading individual points. When the final desired waveform can be composed of simple waveform segments, this is the best way to program the device.

Adding points does not execute the program. The method waveformStart() must be called.

Note

When changing operating mode, the waveform program must be cleared if necessary, because the device will prohibit mixing points from different modes.

Parameters:

frequency : float: The triangle wave frequency. The allowed range is 0.01Hz to 443Hz. The number of points used vary from 3840, for lower frequency waves to 24, for higher frequency waves.
amplitude : float: The triangle wave peak to peak amplitude. The peak to peak amplitude cannot exceed the range defined by the configured operating device limits.
offset : float: The offset of the triangle wave zero amplitude. The offset cannot exceed the configured device limits.
start : float: The starting angle for the triangle wave, in degrees. Allowed range is [0.0, 359.99]
stop : float: The stop angle for the triangle wave, in degrees. Allowed range is [0.01, 360.0]

addWaveform(tp, param1, param2, param3=None)[source]¶: Helper method that implements adding waveform segments.

addWaveformPoints(points, times)[source]¶

Adds a set of points to the waveform program. This is one of the ways that the device can be programmed to generate a complex waveform. It’s the most flexible way, allowing arbitrary waveforms, but it’s also the slowest one (a 10 second waveform may take at least 4 seconds just to upload the program). This method adds more points to the current waveform program. It does not overwrite the existing program.

Adding points does not execute the program. The method waveformStart() must be called.

Note

When changing operating mode, the waveform program must be cleared if necessary, because the device will prohibit mixing points from different modes.

Parameters:

points : array of floats: The array of points to be added to the program. The total number of allowed points may vary, depending on the times array. When the times array has exactly one element, the maximum number of points is 5900. When the times array has at most 126 distinct values, the maximum number of points is 3933. When the times array has more than 126 distinct values, the maximum number of points is 2950.
times : array of floats: The dwell times for each point. Either there must be one time entry for each point, or the array of times must contain exactly one element, which sets the time for all points. The allowed time range is [93e-6, 34e-3] (93µs to 34ms).

cachedMode()[source]¶: Helper method to return cached operating mode

checkError()[source]¶: Helper method to raise an exception if the device reports an error.

clearWaveform()[source]¶: Clears the programmed waveform data. This is required when building a new waveform program. Waveform data can only be cleared while the program is not running.

defaults()[source]¶: Helper method to reset internal data.

getCurrent()[source]¶

Measures the current value. The measured value that is read back is known to have an error (less than 1%) and a delay (up to 320ms).

Returns:	`float`

getCurrentLimits()[source]¶

Gets the negative and positive current limits allowed for operation. The specific limit type that is read depends on the operating mode. When in current mode, the limit set is a main channel limit: it defines the limits of the current that can be programmed by the user. When in voltage mode, the limit is a protection limit: it defines the current limits that the load may impose because of the requested voltage. When changing the operating modes, the set limits no longer apply: they are different for the new mode.

See also: setMode()

Returns:	negative : float The absolute value of the negative limit positive : float The absolute value of the positive limit

getError()[source]¶: Helper method to pop the last error from the device error queue.

getHighLimitValue()[source]¶

Gets either the voltage or current high limit value, depending on operation mode.

Returns:	`float`

getLimits(device, mode)[source]¶: Helper method that implements getVoltageLimits() and :meth: getCurrentLimits

getLowLimitValue()[source]¶

Gets either the voltage or current low limit value, depending on operation mode.

Returns:	`float`

getOperationFlag()[source]¶

Returns the real time value of the device operation condition register. The register contains a set of bits representing the following flags: “list running” (16384), “list complete” (4096), “sample complete” (2048), “constant current mode” (1024), “transient complete” (512)”, “constant voltage mode” (256), “transient armed” (64), “waiting for trigger” (32). Refer to the Kepco BOP GL manual for specific details. The relevant flag used by the library is the “list running” flag, which indicates that theres a waveform program running.

Returns:	`int`

getProgramLength()[source]¶: Helper method that returns the number of points in current waveform program.

getValue()[source]¶

Returns either the readback voltage or the current, depending on operating mode.

Returns:	`float`

getVoltage()[source]¶

Measures the voltage value. The measured value that is read back is known to have an error (less than 1%) and a delay (up to 320ms).

Returns:	`float`

getVoltageLimits()[source]¶

Gets the negative and positive voltage limits allowed for operation. The specific limit type that is read depends on the operating mode. When in voltage mode, the limit set is a main channel limit: it defines the limits of the voltages that can be programmed by the user. When in current mode, the limit is a protection limit: it defines the voltage limits that the load may impose because of the requested current. When changing the operating modes, the set limits no longer apply: they are different for the new mode.

See also: setMode()

Returns:	negative : float The absolute value of the negative limit positive : float The absolute value of the positive limit

getWaveformRepeat()[source]¶

Gets the last requested waveform repeat count.

See also: setMode()

Parameters:	negative : float The absolute value of the negative limit positive : float The absolute value of the positive limit

setLevelWaveform(length, offset)[source]¶

A shortcut to clearing the waveform program, adding a level waveform and setting the repeat count to 1.

Parameters:	length : float Parameter passed to `addLevelWaveform()` offset : float Parameter passed to `addLevelWaveform()`

setLimits(device, mode, negative=None, positive=None, maximum=1e+100)[source]¶: Helper method that implements setVoltageLimits() and setCurrentLimits()

setMode(mode)[source]¶

Changes the operating mode. Supported modes are voltage mode and current mode. In the voltage mode, the device tries to set a specific voltage, while staying within the current protection limits. In current mode, the device tries to set a specific current, while staying within the voltage protection limits. See also: setCurrentLimits(), setVoltageLimits()

Parameters:	mode : {KepcoBOP.MODE_CURRENT, KepcoBOP.MODE_VOLTAGE} The desired mode

setRampWaveform(length, height, offset)[source]¶

A shortcut to clearing the waveform program, adding ramp waveform and setting the repeat count to 1.

Parameters:	length : float Parameter passed to `addRampWaveform()` height : float Parameter passed to `addRampWaveform()` offset : float Parameter passed to `addRampWaveform()`

setSineWaveform(frequency, amplitude, offset, start=0, stop=360)[source]¶

A shortcut to clearing the waveform program, adding sine waveform and setting the repeat count to 1.

Parameters:	frequency : float Parameter passed to `addSineWaveform()` amplitude : float Parameter passed to `addSineWaveform()` offset : float Parameter passed to `addSineWaveform()` start : float Parameter passed to `addSineWaveform()` stop : float Parameter passed to `addSineWaveform()`

setSquareWaveform(frequency, amplitude, offset)[source]¶

A shortcut to clearing the waveform program, adding square waveform and setting the repeat count to 1.

Parameters:	frequency : float Parameter passed to `addSquareWaveform()` amplitude : float Parameter passed to `addSquareWaveform()` offset : float Parameter passed to `addSquareWaveform()`

setTriangleWaveform(frequency, amplitude, offset, start=0, stop=360)[source]¶

A shortcut to clearing the waveform program, adding triangle waveform and setting the repeat count to 1.

See clearWaveform(), addTriangleWaveform(), setWaveformRepeat()

Parameters:	frequency : float Parameter passed to `addTriangleWaveform()` amplitude : float Parameter passed to `addTriangleWaveform()` offset : float Parameter passed to `addTriangleWaveform()` start : float Parameter passed to `addTriangleWaveform()` stop : float Parameter passed to `addTriangleWaveform()`

setValue(v, wait=True)[source]¶

Sets either the current voltage or current, depending on operating mode.

Parameters:	v : float Either voltage, or current to set, depending on operating mode.

setVoltage(voltage, wait=True)[source]¶

Sets the voltage value. This method can only be used when in voltage mode. The voltage values must be within the power supply acceptable range and also within the configured limit values.

Parameters:	voltage : float The desired voltage value

setVoltageLimits(negative=None, positive=None)[source]¶

Sets the negative and positive voltage limits allowed for operation. The specific limit type that is set depends on the operating mode. When in voltage mode, the limit set is a main channel limit: it defines the limits of the voltages that can be programmed by the user. When in current mode, the limit is a protection limit: it defines the voltage limits that the load may impose because of the requested current. When changing the operating modes, the set limits no longer apply: they must be set again for the new mode.

See also: setMode()

Parameters:	negative : float The absolute value of the negative limit positive : float The absolute value of the positive limit

setWaveformAngle(start=0, stop=360)[source]¶: Helper method that configures start and stop angles for sine and triangle waveforms.

setWaveformPoints(points, times)[source]¶

A shortcut to clearing the waveform program, adding waveform points and setting the repeat count to 1.

Parameters:	points : array of floats Parameter passed to `addWaveformPoints()` times : array of floats Parameter passed to `addWaveformPoints()`

setWaveformRepeat(repeat)[source]¶

Set the number of times the waveform program will run. By default, the program runs an indeterminate number of times, until it’s explicitly stopped. This method is used to specify the number of times the waveform program will repeat.

A waveform may also have separate one-shot part and repeatable part. Use the method setWaveformRepeatMark() to separate them.

Parameters:	repeat : int Number of times the programmed waveform will run. A value of zero means run until explicitly stopped.

setWaveformRepeatMark(position=None)[source]¶

Separates the one-short part from the repeating part in the waveform program. By default, the whole waveform repeats, according to the repeat count. This method marks the separation point that allows the definition of an initial one-shot part of the wave. The part before the marked point will be the one-shot part and after the marked point will be the repeating part.