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Need help with Aprilaire 8870

Ad_My_XperienceAd_My_Xperience Junior MemberPosts: 47
Hello,

This is my first residential system and I try to control HVAC with Aprilaire 8870 thermosat.

I asked a question to Aprilaire support about connecting and the response was: Direct to Comm. Port and will handle 64 stats.

1- Can I connect my tstat to my NI-3100 using RS-232 port?
2- Is this parameter correct to set the port: SEND_COMMAND THERMO_8870,"'SET BAUD 19200,N,8,1 485 ENABLE'"
3- I don't want to use the Duet Module, I prefer create one. Someone has a SEND_STRING example?

Thanks

Comments

  • TurnipTruckTurnipTruck Junior Member Posts: 1,485
    You can connect it to a serial port of your NI, but you will wire it according to the RS-422 diagram. Start there then check back in.
  • DHawthorneDHawthorne Junior Member Posts: 4,584
    Yes, the direct buss is RS-422, not 232. I've wired them direct once or twice, but now and again have gotten some inexplicable results ... like thermostat address 1 feedback getting truncated (buss wakeup delay maybe?) in a multi-stat system. But it's no means a consistent issue. My rule of thumb is to try it out direct, and send some basic queries to make sure everything responds properly. If it does not, I add a protocol adapter (supplied by Aprilaire, model 8811 last I checked) to convert it to RS-232 instead of 422. I generally keep a protocol adapter around anyway for troubleshooting via Hyperterminal.
  • ericmedleyericmedley Senior Member - 4000+ posts Posts: 4,177
    DHawthorne wrote: »
    Yes, the direct buss is RS-422, not 232. I've wired them direct once or twice, but now and again have gotten some inexplicable results ... like thermostat address 1 feedback getting truncated (buss wakeup delay maybe?) in a multi-stat system. But it's no means a consistent issue. My rule of thumb is to try it out direct, and send some basic queries to make sure everything responds properly. If it does not, I add a protocol adapter (supplied by Aprilaire, model 8811 last I checked) to convert it to RS-232 instead of 422. I generally keep a protocol adapter around anyway for troubleshooting via Hyperterminal.

    Perhaps I'm just lucky but I've had great results with using the RS422 and the old non-duet comm module. All of the examples of this are 2 or more T-Stats. (In one case 7) I will say that I did have more issues until I started using the Aprilaire 8818 Distribution panel. It is essentially a home-run box that you place at the head-end of your system. Then you connect all the T-Stats to it and then a single line to the control system. It's handy in that it's layed out well, has convenient power/TX/RX on/off switches for each T-Stat.

    I cannot explain why it works better scientifically. It's nothing more than a fancy buss. (Think AMX's AxLink buss) But, using it seems to have solved a whole host off issues using multiple T-Stats.

    At my home, I have 2 8870s on a single AXB-232++ box. (no distribution 8818) It works great.
  • Spire_JeffSpire_Jeff Formerly Caffeinated Programmer Posts: 1,917
    I have used the Duet module connecting directly from an AMX serial port to the HVAC Bus. The duet module seemed to work well with multiple stats.

    Jeff
  • Ad_My_XperienceAd_My_Xperience Junior Member Posts: 47
    This is the situation:

    Pin-outs are:

    Female DB9 Pin 1 ---> B- on 8870
    Female DB9 Pin 4 ---> A+ on 8870
    Female DB9 Pin 6 ---> B+ on 8870
    Female DB9 Pin 9 ---> A- on 8870
    (I don?t use REF connector on the 8870 but don?t know if it?s ok)

    I set the communication speed at 9600 on my 8870.
    My address is 1.
    Max stats = 1.

    In Netlinx, I use Viewstat422_Comm.tko.

    DEFINE_DEVICE
    dvHVAC_422 = 5001:2:0
    dvTP = 10001:1:0
    vdvHVAC_422 = 34001:1:0


    DATA_EVENT[vdvHVAC_422]
    {
    online:
    {
    send_command vdvHVAC_422, "'USEDEBUG-0'"
    send_command vdvHVAC_422, "'SCALE=F'"
    send_command vdvHVAC_422, "'ZONE_COUNT=1'"
    send_command vdvHVAC_422, "'VDV_ONLINE=1'"
    }
    }

    BUTTON_EVENT[dvTP,10] // increase heat set point by one degree
    {
    send_command vdvHVAC_422, "'T-1 HEAT-+'"
    }

    BUTTON_EVENT[dvTP,11] // decrease heat set point by one degree
    {
    send_command vdvHVAC_422, "'T-1 HEAT--'"
    }

    DEFINE_MODULE 'Viewstat422_Comm' myVWSTAT(vdvHVAC_422, dvHVAC_422)

    When I touch button 10 and 11, red output led and yellow input led are flashing but not the Tx and Rx leds on port 2.

    Someone can help me on this issue?

    Thanks a lot!
  • BigsquatchBigsquatch Junior Member Posts: 216
    When using the Viewstat422_Comm module be aware that it will appear to not be working until several minutes after the master has been booted.

    In projects where I use this module, I always check tstat control last when I check system operation. 10 to 15 minutes is not unusual to wait for tstat control from TP's and keypads.
  • Ad_My_XperienceAd_My_Xperience Junior Member Posts: 47
    Wich module is the best if this one is not?
  • viningvining X Member Posts: 4,358
    The one I've been using has the Viewstat422_Comm module in it and I've never had any issues with it.
  • HARMAN_icraigieHARMAN_icraigie Technical Trainer II, Harman Professional University Posts: 531
    Wich module is the best if this one is not?

    Used both the duet and netlinx modules for the Aprilaire tstats. Found that you had to queue the commands going into the netlinx comm while it seemed like you could slam the heck out of the duet module - though its been awhile since I've seen a project with stand alone thermostats.
  • Ad_My_XperienceAd_My_Xperience Junior Member Posts: 47
    Is it normal if Rx ans Tx leds on port 2 (5001:2:0) don't flash when a command is sent?

    Do I need to do something special to configure NI for 422 comm?

    I've check my cable 3 times to be sure but nothing works...
  • viningvining X Member Posts: 4,358
    I've never tried them directly and have always used the 8818 dist. block. I do also pace my commands to the comm mod even though I assumed the comm module already did that, I guess from what icraigie just said maybe it doesn't.
  • ericmedleyericmedley Senior Member - 4000+ posts Posts: 4,177
    Is it normal if Rx ans Tx leds on port 2 (5001:2:0) don't flash when a command is sent?

    Do I need to do something special to configure NI for 422 comm?

    I've check my cable 3 times to be sure but nothing works...

    Perhaps you should try sending an 'RXON' and 'TXON' to the serial port. I've seen a couple times when the port was turned off out of the box. Sending these commands woke it up.

    Just a thought...
  • jazzwyldjazzwyld Registered User Posts: 199
    Like a charm

    I use the non-Duet Module and I've done up to 17 Tstats. I did have to rewrite the UI for to get a lil speedier reaction, since all the feedback is determined by a Level_Event - if the level doesn't update...your TPs don't update. My client also wanted to view all the current room temps in one UI, which was my reason for heavily tweaking that UI anyways. The good thing is other than a few channel differences and variable differences the UI for the new ENV-VST is very similar. I also recommend the multi-zone controller for busing purposes.
  • Ad_My_XperienceAd_My_Xperience Junior Member Posts: 47
    Would you please post code example using Duet Module.

    I still have the same problem: when I send command to the virtual device HVAC, COM port doesn't flash...

    Is it possible to post detailed connections into your 8870 because I don't know if I need to connect R and C wires.
  • viningvining X Member Posts: 4,358
    R & C on the bus connection side powers the stat. RC & RH on the HVAC control wiring side is for cooling & heating respectively is power to pull the required HVAC control relays. You don't need the RH or RC to establish comms but you do need the R & C for obvious reasons. Now the R & C doesn't come from AMX you need a sperate 24vac power supply for that. Tapping power from a conditioned power source is recommended.

    So you need the A's & B's and R & C.
  • Ad_My_XperienceAd_My_Xperience Junior Member Posts: 47
    Hello guys,

    As suggested by DHawthorne, I've bought the protocol adapter 8811.

    I connect RX's with respective TX's and when I send a command, I see both TX and RX leds flash.

    When I connect the protocal adapter to the tstat and I send a command, RX RS-232 and TX RS-485 flash but they flash very fast and the leds don't have the maximum light (flashing leds are very light).

    Is there a way to test communication on tsat or change something on (dip switch, etc.).

    I'm stuck on this problem for 3 weeks...

    Thanks
  • ericmedleyericmedley Senior Member - 4000+ posts Posts: 4,177
    Hello guys,

    As suggested by DHawthorne, I've bought the protocol adapter 8811.

    I connect RX's with respective TX's and when I send a command, I see both TX and RX leds flash.

    When I connect the protocal adapter to the tstat and I send a command, RX RS-232 and TX RS-485 flash but they flash very fast and the leds don't have the maximum light (flashing leds are very light).

    Is there a way to test communication on tsat or change something on (dip switch, etc.).

    I'm stuck on this problem for 3 weeks...

    Thanks

    You can monitor what the serial port is sending and receiving in Diagnostics. Set up a watch on the port and enable it. You'll see a rolling text of all the traffic to and from the port. Diagnostics is available in NS3 or Netlinx Diagnostics, a stand-alone program.
  • DHawthorneDHawthorne Junior Member Posts: 4,584
    The way I use a protocol adapter to troubleshoot is to plug the computer into the and connect with Hyperterminal, setting up the serial port to match your stat parameters. Then type in "SN T?" and all the thermostats on the buss should report back their temperatures. If they don't, you have a problem with the thermostats themselves ... or if one or two don't report, with those specific stats. If you get garbage in response to the query, the baud rate is wrong. If you get garbage all the time, whether you are sending something or not, you have a bad thermostat, and you have to turn off the comms on each, one at a time until you find the bad one. You have to reset all of then between every try though, once the garbage cycle starts, they all get messed up and just turning off the bad one alone won't bring them back. I sometimes find it easier to turn them all off, then turn one on at a time till it goes wiggy.
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