Voltage Outputs

ExpEYES-17 / SEELab3 provides two programmable voltage sources driven by a 12-bit DAC:

Output	Range	Notes
PV1	−5 V to +5 V	Independent DAC channel
PV2	−3.3 V to +3.3 V	Independent DAC channel

Both return the actual voltage set after accounting for 12-bit resolution limits.

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set_pv1 : Set Voltage on PV1

p.set_pv1(value)

Set output voltage on PV1 (−5 to +5 V).

parameter	description
value	between −5 to 5 V
return	Actual set voltage after accounting for resolution limitations (12-bit)

x = p.set_pv1(2)

import eyes17.eyes
p = eyes17.eyes.open()
actual = p.set_pv1(2)
# Connect PV1 to A1
print('Set voltage =', actual)
print('Voltage at PV1 =', p.get_voltage('A1'))

set_pv2 : Set Voltage on PV2

p.set_pv2(value)

Set output voltage on PV2 (−3.3 to +3.3 V).

parameter	description
value	between −3.3 to 3.3 V
return	Actual set voltage after accounting for resolution limitations (12-bit)

x = p.set_pv2(1)

import eyes17.eyes
p = eyes17.eyes.open()
actual = p.set_pv2(1)
# Connect PV2 to A1
print('Set voltage =', actual)
print('Voltage at PV2 =', p.get_voltage('A1'))

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get_pv1 / get_pv2 : Last set voltage

Return the last voltage commanded on each DAC channel (software copy, not a fresh ADC measurement).

p.set_pv1(2.5)
print(p.get_pv1())   # ≈ 2.5 (nearest 12-bit code)
print(p.get_pv2())   # last value set on PV2

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Diode Clipping Demonstration

import eyes17.eyes
p = eyes17.eyes.open()
from matplotlib import pyplot as plt

p.set_sine(200)
p.set_pv1(1.35)       # will clip at 1.35 + diode drop

t, v, tt, vv = p.capture2(500, 20)   # captures A1 and A2

plt.xlabel('Time(mS)')
plt.ylabel('Voltage(V)')
plt.plot([0, 10], [0, 0], 'black')
plt.ylim([-4, 4])

plt.plot(t, v, linewidth=2, color='blue')
plt.plot(tt, vv, linewidth=2, color='red')

plt.show()

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Current sources

Source	Device	Control	Current
CCS	ExpEYES-17	p.set_state(CCS=True/False)	Fixed ~1.1 mA (p.currentSourceValue)
PCS	SEELab3	p.set_pcs(mA) / p.get_pcs()	Programmable ~0–3.3 mA (via PV2)

CCS — constant current (ExpEYES-17)

On ExpEYES-17, CCS is a fixed constant-current source (typically ~1.1 mA after calibration). Turn it on/off with digital state control — see Digital I/O.

p.set_state(CCS=True)
print('CCS ≈', p.currentSourceValue * 1e3, 'mA')
p.set_state(CCS=False)

PCS — programmable current (SEELab3)

On SEELab3, PCS is a programmable current source derived from the PV2 DAC (not available as a separate CCS switch on that product line in the same way):

\[ \mathrm{PCS\,(mA)} = 1.65 - 0.5 \times \mathrm{PV2\,(V)} \quad\Leftrightarrow\quad \mathrm{PV2} = 3.3 - 2 \times \mathrm{PCS} \]

Useful range is about 0 to 3.3 mA (compliance ~3 V). Setting PCS remaps PV2; do not use set_pv2 for an independent voltage while PCS is in use.

set_pcs / get_pcs

p.set_pcs(val) — val in mA. Returns the actual current set (mA) after DAC quantization.

p.get_pcs() — returns the last commanded PCS current (mA).

import eyes17.eyes
p = eyes17.eyes.open()

actual = p.set_pcs(1.0)   # aim for 1 mA (SEELab3)
print('PCS set to', actual, 'mA')
print('Last PCS =', p.get_pcs(), 'mA')
print('Underlying PV2 =', p.get_pv2(), 'V')