Cool - it’s still around: https://modbus.org/docs/PI_MBUS_300.pdf <https://modbus.org/docs/PI_MBUS_300.pdf>
ASCII is easy to build, RTU a little tougher due to the timing requirements. This brings back some memories… probably happily forgotten. The protocol was originally designed for talking to Modicon Programmable Logic Controllers. The documentation has lots of references to specific controllers like 384, 484, 984, etc. Read Coil, Read Input, Force Coil, etc. all refer to reading or setting an individual real world input/output or storage bit on or off. Registers are words (integers normally, but can be anything). You need detailed descriptions of the mapping of addresses on the devices you want to control to be able to understand what you are controlling. Mark > On Aug 19, 2020, at 7:45 PM, Matt Corcoran <[email protected]> wrote: > > Not quite related, but I just found out that Microtik(linux) has built in > drivers for common Arduino serial chips. I setup an Arduino to monitor 4 > different voltages at our solar site. Our NMS just SSHs to the > microtik(special login) to pull the average voltages and graph them. I was > happy to not add any more equipment other than the power sipping Arduino. > > > > Matt Corcoran | Network Engineer > [email protected] <mailto:[email protected]> | 231-680-0062 > > <image001.png> <http://stratospeed.com/index.html> > > www.stratospeed.com <http://www.stratospeed.com/> | 231-774-2112 > > > > > > From: AF <[email protected] <mailto:[email protected]>> on behalf > of dave <[email protected] <mailto:[email protected]>> > Reply-To: AnimalFarm Microwave Users Group <[email protected] > <mailto:[email protected]>> > Date: Wednesday, August 19, 2020 at 4:19 PM > To: "[email protected] <mailto:[email protected]>" <[email protected] > <mailto:[email protected]>> > Subject: Re: [AFMUG] OT odd data connection > > Ive done alot with Modbus on arduino products interfacing with anything that > speaks modbus. > I have a server I que or add each thing I want to monitor or review. > Temps, Humidity power levels or presence of are the main ones. > > > > <image002.jpg> > On 8/19/20 11:26 AM, [email protected] <mailto:[email protected]> wrote: >> On one of my large portable air compressors, there is a data port. They >> sell an adapter cable for about $200 It adapts it to USB. The program that >> you use to talk to it makes reference to modbus. >> >> The data port has 4 pins. RJ-10 4p4c connector. >> +5 with enough current to light an incandescent light bulb. >> +5 low current >> +5 low current >> Ground >> >> This sounds like USB host to me. One of my sons think it is RS-485 >> >> I don’t think USB would be happy on a RJ-10 and utp wire. Maybe it would. >> Maybe I am just buying a piece of wire with two connectors on the ends. >> >> The controller it plugs into is $2000 so I don’t want to experiment on that. >> Be interesting to see the adapter cable when it gets here. See if there >> are any active components. I would have probably just wired it up to a USB >> and tried it if my son had not made the modbus/RS485 comment. >> >> Any guesses? >> >> > > > -- > AF mailing list > [email protected] <mailto:[email protected]> > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <http://af.afmug.com/mailman/listinfo/af_af.afmug.com>
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