Internet PLC Forum

Yes the fuel sensor is a basically a variable resistance with 90 ohm empty, and zero ohm full.  It is only 2 terminals, not 3 like a pot. I was trying to limit the 5 volt reference current to less than 4ma (less than half the 10ma limit without changing RA3) to allow some capacity for other sensors. Then resistance to ground then needs to be around 1K ohms to ground, so the total resistance is 1090 ohm at empty, and the voltage measured zero to .41 volts.  The .41 is 8% of the ADC 5 volt full scale and 4096 * .08 / 4 = 84 steps, which is acceptable. I would prefer to have more current of the 5 volt reference available for other sensors, but think I could live with that.  If my thinking is off, don't hesitate to comment.

Someone has suggested using an OP AMP, which I am learning with a little help. At this point my expertice is a little more than E = IR, just enough to be dangerous, but I can see far enough to build up a breadboard and see what happens.  

I have a T100MD-888+, MD-EXP4040, and a MD-HMI. The T100 manual shows a 1 amp fuse for the T100MD, but no fuses are shown for the other boards. Should the other boards be fused,? value?, parallel fuses?, or one larger fuse for all?  Of course all going to the same power supply, mine happens to be 12 DC.

On the T100MD-888+, the high current ground - all in/output grounds (returns) should go there, to an off the boards ground point (with short proper capacity (amps) wire)  with the exception of the TTL & Cmos in/out on the MD-EXP4040 which have their own grounds on the headers.
 

Have a T100MD+, trying to communicate with serial port to PC.  From TL server 2.1 am able to set port, and with command string IR*, get appropriate response.  Then from Trilogi 5.3 try to set PLC clock, and after clock settings window get "log in to TLServer" window, where it wants IP address. I must be missing something dumb.

Yes, the lead-acid battery is used to start the generator, but it's a gasoline 27 hp., 2 cyl. Kohler engine. No load battery voltage is 12.7 volts, cranking 12.0 volts. The battery is severely oversized with respect to the engine for normal applications. Was thinking the battery is there, and kept charged, why not use it as the UPS, and eliminate one more piece of equipment to maintain (a separate UPS), but maybe that's a better way to go, a UPS meant for a PC could easily bridge the power outages and aren't that expensive. I was thinking an electronic relay circuit controlled by the 120 volt supply would switch quick enough to keep the PLC from resetting .

On a T100MD888, how would I measure the frequency and voltage of 120/240 volt 60 HZ power using the pulse width and ADC features of the PLC. Object would be to set alarms if out of range.  

With a T100MD888, how would I start an event every "N" weeks. The application is an exerciser for a standby generator.

Also assuming with Basi will be able to display time, day, date on attached display.