8270 Solid State Chassis Simulator
This is a program which simulates the logic circuit of an 8270 solid state chassis (using Omega Tek MK70 or the original 5 boards - their logic is mostly the same).
I built this for fun but it's a useful tool for learning about and troubleshooting 8270 electronics. The download also includes the C# source code if you're interested.
The simulator is written in C# and uses a boolean logic expression tree to mimic the omegatek logic design and formulate the 'states' of the machine, and thus the behaviour you see on screen.
It needs the .Net framework v4 (most up-to-date Windows 7+ PCs have this already and it will ask to install it if not).
- It's fairly simple to operate. You can see and activate all the input switches. You can see all the chassis outputs (plus some internal logic states there for interest).
- Left clicking an input activates it (e.g. click 'Cycle' to activate the cycle input).
- The cam switches activate automatically as the 'motors' turn, but you can also click them to cause havoc as you please.
- You can also turn off the table or sweep. You can even unplug the table or sweep (so that the 'contactor' operates, but the cams don't advance).
- Holding the Ctrl key on your keyboard and clicking an input "locks" the input in that state. You can also Ctrl-Right-Click an input to lock the input off. This allows you to simulate a broken microswitch - either in the on state or off state, or for example, allows continuous cycle.
- You can also pause, stop and run the simulation at normal or slow speeds.
- All of the visual elements you see are simply reflections of the internal logic state machine, which I designed to mimick the actual boolean logic design of the Solid State chassis. There is no animation programming of the motions of the machine - it is all purely re-evaulating the logic states at timed intervals to produce the observed movements (which is how a solid state chassis works, unlike the 'programmed' operation of the XOP or MP chassis. In fact, the entire "brains" of the chassis are represented by a couple of dozen lines of code which express the boolean algebra contained in the TTL chips and connections of the solid state boards (OmegaTek board).
- What is interesting about the fact that the simulator is a state machine is that you can fiddle with the inputs at any stage and - in theory - produce "wrong" behaviour that you would observe on a real machine with SS chassis. For example, try cycling the machine, wait until the sweep drops and then hold SC out. When the timer expires, the machine will interlock. This is exactly what happens on a real machine (e.g. when the sweep is slack and overruns first guard far enough to activate SC). The interesting point is I did NOT program this particular behaviour into the simulator. I simply programmed the state machine logic - and a facet of that logic is that SC will cause the sweep to run into the table (interlock) on first ball if the sweep overruns first guard too much. Or, hold out TA2 and flick the SA cam - the machine will step cycles - again, I didn't program this specific case - just the boolean logic which happens to result in that behaviour (by design of course - that's what changes the chassis between cycles normally). In theory, any behaviour, including 'odd' behaviour is represented - I didn't have to program each of these behaviours - they are an implicit side-effect of programming only the internal boolean logic.