2.35  PRINT command

2.35.1  Syntax

print mode points ... ...
print mode + points ... ...
print mode - points ... ...
print mode CLEAR

2.35.2  Purpose

Select points in the circuit for tabular output. Select tabular output.


The `print' command selects where to look at the circuit, or where to hook the voltmeter (ammeter, watt meter, ohm meter, etc.) probe.

There are separate lists of probe points for each type of analysis.

To list the probe points, use the bare command `print'.

On start-up, probes are not set. You must do the command `print op v(nodes)' or put `.print op v(nodes)' in the circuit file to get any output from the op command.

Syntax for each point is parameter(node), parameter(componentlabel), or parameter(index). Some require a dummy index.

You can access components in subcircuits by connecting the names with dots. For example: R56.X67.Xone is R56 in X67 in Xone. Some built-in elements, including diodes, transistors, and mosfets, contain subcircuits with internal elements. Cgd.M12 is the gate to drain capacitor of mosfet M12.

If the component does not exist, you will get an error message. If the component exists but the parameter is not valid for that type, there will be no error message but the value printed will be obviously bogus.

The options plot and noplot on any analysis command turn plotting on and off a single run. The plot command turns plotting on and tabular output off. The print command turns plotting off and tabular output on.

You can add to or delete from an existing list by prefixing with + or -. print ac + v(3) adds v(3) to the existing set of AC probes. print ac - q(c5) removes q(c5) from the list. You can use the wildcard characters * and ? when deleting.

For AC analysis, by adding a suffix letter to the parameter, you can get the magnitude M, phase P, real part R, or imaginary part I. Adding DB gives the value in decibels, relative to 1. For example, VRDB(R13) gives you the real part of the voltage across R13, in decibels.

2.35.4  Node probes

Several parameters are available at each node.

All modes


All except Transient

Impedance looking into the node.

Transient, DC, OP only

A numeric interpretation of the logic value at the node. The value is displayed encoded in a number of the form a.bc where a is the logic state: 0 = logic 0, 1 = rising, 2 = falling, 3 = logic 1. b is an indication of the quality of the digital signal. 0 is a fully valid logic signal. Nonzero indicates it does not meet the criteria for logic simulation. c indicates how the node was calculated: 0 indicates logic simulation. 1 indicates analog simulation of a logic device. 2 indicates analog simulation of analog devices.

The most recent time at which the logic state changed.

The scheduled time a pending logic state change will occur.

AC only

In addition to those listed here, you can add a suffix (M, P, R, I and db) for magnitude, phase, real part, imaginary part, and decibels, to any valid probe.
Imaginary part of the voltage.

Decibels relative to 1 v.

Imaginary part of the impedance looking into the node.

Impedance phase (angle between voltage and current).

2.35.5  Status probes

There are several status variables that can be probed.

All modes

The simulation temperature in degrees Celsius.

The current time in a transient analysis. In AC analysis it shows the time at which the bias point was set, 0 if it was set in a DC or OP analysis, or -1 if it is the bias was not set (power off).

Transient, DC, OP only

The output of the “signal generator”. In a transient analysis, it shows the output of the signal generator, as set up by the generator command. In a DC analysis, it shows the DC input voltage (not the power supply). In an OP analysis, it shows the DC input, normally zero.

The number of iterations needed for convergence for this printed step including any hidden steps.

The number of iterations needed for convergence for this printed step not including any hidden steps.

The total number of iterations needed since startup including check passes.

A number indicating why the simulator chose this time to simulate at.
1 The user requested it. One of the steps in a sweep.

2 A scheduled discrete event. An element required a solution at this time.

3 The effect of the “skip” parameter.

4 The iteration count exceeded ITL4 so the last step was rejected and is being redone at a smaller time step.

5 The iteration count exceeded ITL3 so the increase in time step is limited.

6 Determined by local truncation error or some other device dependent approximation in hopes of controlling accuracy.

7 Determined by a movable analog event. An element required a solution at this time.

8 The step size was limited due to iteration count.

9 This is an initial step. The size was arbitrarily set to 1/100 of the user step size.

10 + x The previous step was rejected.

20 + x A zero time step was replaced by mrt.

30 + x The required step size less than mrt, so it was replaced by mrt.

The number internal time steps. (1 if all steps are printed. One more than the number of hidden steps.)

2.35.6  Element probes

Each element type has several parameters that can be probed. In general, the form is Parameter(element). Wild cards are allowed in element names to allow probing the same parameter of a group of elements.

For components in a subcircuit, the names are connected with dots. For example R12.X13 is R12 in the subcircuit X13.

Most two node elements (capacitors, inductors, resistors, sources) and four terminal elements (controlled sources) have at least the following parameters available. Others are available for some elements.

All modes

Branch voltage. The first node in the net list is assumed positive. This is the same as “output voltage”.

Output voltage. The voltage across the “output” terminals.

Input voltage. The voltage across the “input” terminals. For two terminal elements, input and output voltages are the same.

Branch current. It flows into the first node in the net list, out of the second.

Branch power. Positive power indicates dissipation. Negative power indicates that the part is supplying power. Its value is the same as (PD - PS). In AC analysis, it is the real part only.

Nominal value. In most cases, this is just the value which is constant, but it can vary for internal elements of complex devices.

The effective value of the part, in its units. If the part is ordinary, it will just show its value, but if it is time variant or nonlinear, it shows what it is now.

Resistance. The effective resistance of the part, in ohms. In AC analysis, shows the magnitude of the self impedance. In OP, DC or TRansient analysis, shows its incremental resistance. In TRansient analysis, it shows the effective Z-domain resistance of inductors and capacitors.

Admittance. 1/R.

All except Transient

Impedance at a port. The port impedance seen looking into the circuit across the branch. It does not include the part itself. In transient analysis, it shows the effective Z-domain impedance, which is a meaningless number if there are capacitors or inductors in the circuit.

Impedance at a port, raw. This is the same as “Z” except that it includes the part itself.

Transient, DC, OP only

These parameters are available in addition to the above.
Branch power dissipated. The power dissipated in the part. It is always positive and does not include power sourced.

Branch power sourced. The power sourced by the part. It is always positive and does not consider its own dissipation.

The result of evaluating the function related to the part. It is the voltage across a resistor, the charge stored in a capacitor, the flux in an inductor, etc.

The “input” of the device. It is the current through a resistor or inductor, the voltage across a capacitor or admittance, etc. It is the value used to evaluate nonlinearities.

The offset current in the device. The current through a nonlinear device can be considered to have two parts: a passive part and an offset.

The passive part of the current.

AC only

In addition to those listed here, you can add a suffix (M, P, R, I and DB) for magnitude, phase, real part, imaginary part, and decibels, to any valid probe. Negative phase is capacitive. Positive phase is inductive.
Reactive (imaginary) power, volt-amps reactive.

Decibels relative to 1 va reactive.

Volt amps, complex power.

Decibels relative to 1 va.

Power phase (angle between voltage and current).

2.35.7  Examples

print ac v(12) v(13) v(14)
The voltage at nodes 12, 13, and 14 for AC analysis.

print dc v(r26)
The voltage across R26, for DC analysis.

print tran v(r83) p(r83)
Voltage and power of R83, for transient analysis.

print dc i(c8) p(r5) z(r5)
The current through C8, power dissipated in R5, and the impedance seen looking into the circuit across R5.

print op v(nodes)
The voltage at all nodes for the op command.

List all the probes, for all modes.

print op
Display the OP probe list.

print ac clear
Clear the AC list.