ISIS and VSM Newbie

retepsnikrep

Senior Member
OK I have invested in the software and drawn up the design of a circuit I want to simulate/mess about with.

Basically it is powered by a high capacity lithium cell and measures it's own voltage against a reference, two OP amps provide an over and under V trip which turns on the appropriate opto's and a load balancing resistor in the case of an Over V situation.

However the software learning curve is very steep, so I have a number of questions.

1) How exactly do I alter a pot's default value? I can place a generic pot on the circuit and I have changed the VALUE but is that right? I can't find an idiots reference to it in the help :confused:

2) I'm also confused about power rails and supplies, the circuit will be powered from the lithium cell which will range from +2.5 to +4.25v. Should I add a battery and wire everything to that?

3) When I try to simulate it I get two errors

No model specified for D1
Simulation failed due to partion analysis errors.
4) I would also like to power the circuit in the simulation from an adjustable 2-5v power supply so I can see if it triggers correctly as V rises or falls, is this possible?

5) Also the text in the bottom right hand corner box is overlaying itself and I can't see how to correct it :(

Just learning so thanks for help in advance. Feel free to correct my errors on the attached and re-upload it :)
 

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Technical

Technical Support
Staff member
1) You have used a generic (fixed value) pot rather than an animating one. Try replacing it with the similar device in the PICAXE category - these all animate. You then adjust the slider to change the value as the animation is running.

2) When starting off just use power rails, its simplest. But don't use you own named terminal (you have used a terminal called cell V+) just use the default power terminal. To change the power rail value use Design>Configure Power rails menu to adjust the voltage from the (default) 5V.

3) ISIS contains both schematic (symbol only, no simulation) and simulating components. You happen to have picked a component that does not simulate here - hence the error message. Swap to a similar simulating device (ie a component that has a MODFILE property)

4) as 2)

5) The titles etc. should be set via the Design>Edit design properties menu. You have laid extra text over the template values here. Have a look at the ISIS template tutorail for more details.
 
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retepsnikrep

Senior Member
Nearly there!

1) You have used a generic (fixed value) pot rather than an animating one. Try replacing it with the similar device in the PICAXE category - these all animate. You then adjust the slider to change the value as the animation is running.

2) When starting off just use power rails, its simplest. But don't use you own named terminal (you have used a terminal called cell V+) just use the default power terminal. To change the power rail value use Design>Configure Power rails menu to adjust the voltage from the (default) 5V.

3) ISIS contains both schematic (symbol only, no simulation) and simulating components. You happen to have picked a component that does not simulate here - hence the error message. Swap to a similar simulating device (ie a component that has a MODFILE property)

4) as 2)

5) The titles etc. should be set via the Design>Edit design properties menu. You have laid extra text over the template values here. Have a look at the ISIS template tutorail for more details.
Thanks I sorted out most of the errors above and added a few volt meters but the circuit/simulation does not run/perform as I expect giving two errors

Gmin stepping failed and Gmin 0-120 failed. :confused:

I looked at help and it suggested change the op amp properties to a generic type but I can't see how to do that.

I have uploaded the latest version any ideas?
 

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Labcenter

New Member
Are these errors or warnings ?

The GMIN value defines the leakage of reverse biased semiconductor junctions and other theoretical points of infinite impedance. Reducing this value may help achieve convergence for circuits that fail to simulate - although this may be at the expense of simulation accuracy. You can do this from system - set animation options - spice options; Note that values greater than 1E-9 will likely give dubious results.
 
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