in post #18 Lionel said:
besides the basic idea of using inexpensive “tileboard” as the background for the trainer, here are a couple of other ways to save money on the “simulated machine” project ...
for switches (inputs) use regular “wall mounted” light switches from Lowes or Home Depot ... the cheapest ones will work fine for your purposes and they only cost about $0.57 each the last time I checked ... you can mount these through the tileboard by just whittling a suitable hole to poke the switch lever through – no “switch plate” needed unless you want to get fancy with it ...
as for light bulbs (outputs) get a string of Christmas tree lights ... be sure to get the larger bulbs (about 3 to 7 watts each ) rather than the tiny bulbs that all run in series ... it’s a lot easier to wire up the larger bulbs since each one can run on a full 120 volt signal ... cut the string of lights apart and you’ll have twenty (or more) sockets and bulbs ... buy these on sale right after Christmas and you’ll probably only have to spend $3.00 or less for the whole set ... and the various colors will come in handy to dress up your simulator board ... right now I’m thinking of green, yellow, red ... heck, we’ve got a terrific “traffic light” simulator coming together here ... anyway ... whittle some appropriately-sized holes through the tileboard ... if you get the hole just the right size, then the bulb can stick out on the front and still screw into the socket which stays behind the board ... or a little bit fancier: build a “frame” (basically four strips of 1-by-2) and mount a piece of tileboard on the front and another piece of tileboard on the back ... then make smaller, neater holes for just the tip of the lamps to poke through the “front” and mount the sockets on the “back” board using a “hot glue” gun to hold them in place ...
for the I/O wiring you can save quite a bit of money by skipping the terminal strips and just leaving the “field-end” of each wire permanently attached to its switch or lamp bulb ... leave each wire about 5 or 6 feet long to make it easier to connect to the PLC’s input and output modules ... #16 gauge wire is usually a good choice ... the more flexible the better ...
since you’ll probably be working with 120 VAC somewhere along the way, here’s an idea to make that operation a lot safer ... put together a benchtop “power supply board” like this one ... basically it just inserts a 100 watt lamp in series with the 120 volt “hot” wire ... sort of like adding in an extra “fuse” ... the big difference is that the lamp bulb “fuse” won’t blow out if you happen to make a mistake and wire up a dead short ... or if a live wire somehow gets away from you and makes its way to ground ... now you WILL still be able to get enough “juice” through the bulb to shock you, so you still have to be careful ... but this little rig will make all of your 120 VAC powered experiments a lot safer than just plugging your toys directly into a wall outlet ... note that the “bypass switch” is shown in red because it’s optional ... basic idea: if the load that you hook up through this thing is too heavy, then the lamp bulb will start to glow ... and as the load gets heavier and heavier, you’ll eventually reach a point where the bulb is dropping too much voltage and the loads won’t properly energize ... by switching the optional “bypass switch” to the ON position, you’ll bypass the bulb and feed the full 120 volt supply to your experimental load ... NOTE: if the lamp comes on “full bright” when you first try turning on the load, then do NOT turn on the “bypass switch” ... you’ve probably wired up a dead short ... check your wiring before you go any further ... the good news is that as long as the “bypass switch” stays OFF, even a dead short won’t cause any arcing and sparking ... and you won’t have to track down a new fuse before getting back in business ... and (big advantage) you’ll have a handy “main switch” to easily turn the power off and on as you wire up your various experiments ...
if you try any of this, keep us posted on the results ... I’ve seen some local guys get quite elaborate with their tileboard trainers ... if I remember correctly they told me that they had less than $50.00 in the whole setup ... and beside the paint booth (in the link above) they had a conveyor, a press, and one or two other simulated “machines” laid out on various pieces of tileboard ... all ready to be wired up and programmed with whatever PLC they could come up with ...
