Run a static operating point or DC source sweep

Choose the right analysis

.OP returns one selected static equilibrium, with node voltages, phase-node values, component currents and convergence scalars. It creates no time-domain waveform. .DC repeats static solves for one independent DC current or voltage source; every point starts from zero.

Use a matching 2.9 installation and valid licence. Keep one standalone OP or DC analysis in the deck. Do not add .TRAN, .STEP, .PRINT/.SAVE/.PLOT, .MEASURE or explicit .IC to these examples. A running junction’s average voltage, switching and hysteresis require dynamical analysis.

Save op_bias.cir

* Static subcritical Josephson equilibrium
.MODEL MOD JJ(IC=1m RN=5 R0=100 C=1p VG=2.8m)
I1 0 N DC 0.5m
L1 N J 2p
B1 J 0 MOD
.OPTION SEED=321
.OP
.END

Run and inspect the operating point

1. Open the saved op_bias.cir source. Run > Analysis workbench can inspect or edit its OP entry; review and acknowledge any proposed source change before Apply, then save. Apply does not run the calculation.
2. In Run settings choose a separate writable Primary native output such as op.csv. Save and preview the saved run plan, then use the normal Run action.
3. Read the task verdict and document status. A successful .OP presents its scalar Results table and task output; the document status is Results current. The absence of a waveform plot is expected.
4. Check scalar names and units, including P(J), I(L1) and OP.normalized_residual. A retained failure receipt or visible table is not proof of numerical success.

josim-pro-cli -P 17 -o op.csv op_bias.cir

Check the operating-point values

For this 0.5 mA bias and 1 mA sinusoidal junction, the selected junction phase is asin(0.5) = π/6 ≈ 0.523598776 rad. The superconducting nodes N and J have zero physical voltage, and I(I1), I(L1) and I(B1) are 0.0005 A in their declared first-to-second-terminal directions.

The report has one header and one numeric row. P(node) is phase in radians, V(node) is volts and I(component) is amperes. P(N) is not the same quantity as the junction-node P(J); the inductor contributes a phase difference.

Success requires OP.normalized_residual <= 1 under the static solver’s configured equation scales and phase-correction criterion. A small or zero reported residual is numerical convergence evidence, not physical accuracy, stability or root uniqueness. Transient timestep and integrator settings do not define this equilibrium.

Save dc_divider.cir

* Independent static points, not a transient or hysteresis curve
V1 IN 0 DC 42
R1 IN OUT 10
R2 OUT 0 30
C1 OUT 0 1p
.OPTION SEED=321
.DC V1 -2 2 1
.END

Run a DC source sweep

1. Open the saved dc_divider.cir. In the Analysis workbench, DC selects V1 and start -2, stop 2, increment 1, in volts. The supplied source already contains this analysis; inspect or edit it instead of adding a second one.
2. Choose a distinct native result path such as dc.csv, save/preview the complete plan and run. A nonzero increment must point toward the stop value.
3. Inspect every point and its convergence data. The horizontal axis is Sweep(V1) in volts, not time in seconds; current plots may display mA while native CSV keeps A.

josim-pro-cli -P 17 -o dc.csv dc_divider.cir

Check the DC curve and direction

The CSV starts with Sweep(V1) (V). The checked points -2, -1, 0, 1 and 2 V produce V(OUT) values -1.5, -0.75, 0, 0.75 and 1.5 V. Capacitors are exactly open in this static solve, so I(C1) is zero. The original DC 42 source declaration is overridden by each requested sweep point without editing the input file.

Use the following descending variant to retain the reverse source order. An aligned endpoint is included; an unaligned stop does not create a shortened last interval. There are at most 4,096 points, with finite literal range values and no nested/two-source sweep in this interface.

Both CLI and native GUI results match the supplied equations. Gzip reports reopen with the same values. These simple examples do not validate measured-device behaviour, every supported static model or arbitrary circuit tolerances.

Save dc_descending.cir

* Independent static points, not a transient or hysteresis curve
V1 IN 0 DC 42
R1 IN OUT 10
R2 OUT 0 30
C1 OUT 0 1p
.OPTION SEED=321
.DC V1 2 -2 -1
.END

Recover without accepting a partial or failed result

Changing the OP current to 1.5 mA caused “No converged static operating point from the zero-start state” in the checked case. The GUI identified Run failed and retained a specific failed task; the previous report stayed intact. Reopening the valid 0.5 mA source and running to a new destination recovered the scalar result.

A DC point above the static junction’s supported equilibrium failed at the reported point index without publishing a partial curve or replacing an existing report. Correct the bias/model or choose an appropriate transient analysis; do not interpret the uncommitted prefix as a complete curve.

For a rejected range, correct the zero/wrong-direction increment and preview again. Remove streaming or unsupported report targets: OP/DC use CSV or CSV.gz, not waveform RAW/BIN/STDOUT. Keep the old report as a separate record and verify the fresh task verdict, filename and data.