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  1. #1
    Join Date
    Dec 2006
    Location
    Boston area
    Posts
    255

    Modbus boiler integration problem

    Patterson Kelley "Envi" boilers. Issue is a few points are not coming in properly.
    Low Water is always in alarm, switching it didn't help.
    Boiler ignition count also not increasing.
    Boiler High,Med,Low runtimes (hours) not working.

    Hoping someone may have had same issues in the past and came up with a solution.

  2. #2
    Join Date
    Apr 2009
    Location
    Mobile, AL.
    Posts
    88
    Quote Originally Posted by mechmike2 View Post
    Patterson Kelley "Envi" boilers. Issue is a few points are not coming in properly.
    Low Water is always in alarm, switching it didn't help.
    Boiler ignition count also not increasing.
    Boiler High,Med,Low runtimes (hours) not working.

    Hoping someone may have had same issues in the past and came up with a solution.
    Check the register addresses for those data points. If you have the other data in a modbus read then thr ones you are missing may have incorrect addressing.
    The single points are usually bit mapped and part of a single byte. Values would be bytes or words.
    Modbus is a very common communications system, but the addressing must be correct.
    This applies if you are getting any information from this drop.
    No dat amy be a modbus problem on addressing, baud rate etc.

  3. #3
    mechmike2



    Did you get this resolved? If you send a copy of the manual to me I can see what I can do to help. We regularly integrate equipment with modbus.

  4. #4
    Join Date
    Aug 2012
    Location
    Phoenix, AZ
    Posts
    24
    Anyone get these resolved?
    I have the same issues with those points.

    I mapped the supply temp as Numeric Bit point as Hex 0 with
    Beginning Bit 0 and number of bits 8 then I did the conversion and it works.
    Also, I figured out the CH setpoint and DHW setpoint but
    I get a write error when I try to write to them.

    Low Water is always in alarm, switching it didn't help.
    Boiler High,Med,Low runtimes (hours) not working.

    Are these mapped as Numeric Bits Points?

  5. #5
    Join Date
    Aug 2012
    Location
    Phoenix, AZ
    Posts
    24
    Quote Originally Posted by jaceski View Post
    Anyone get these resolved?
    I have the same issues with those points.

    I mapped the supply temp as Numeric Bit point as Hex 0 with
    Beginning Bit 0 and number of bits 8 then I did the conversion and it works.
    Also, I figured out the CH setpoint and DHW setpoint but
    I get a write error when I try to write to them.

    Low Water is always in alarm, switching it didn't help.
    Boiler High,Med,Low runtimes (hours) not working.

    Are these mapped as Numeric Bits Points?


    ANYONE??

  6. #6
    Join Date
    Jan 2012
    Location
    California
    Posts
    92
    Modbus is kind of tricky and some don't follow standards to begin with. I could help you with ALC but you should get a program that allows you to read the raw data and see what the boiler is responding. Getting some to work is a good start and tells you you are setup correctly wiring wise at least. Also some manufactures will not allow you to write to them. Really not sure without seeing the manufactures data. Sorry....

  7. #7
    Join Date
    Aug 2012
    Location
    Phoenix, AZ
    Posts
    24
    Mach-Boilers.pdf
    Quote Originally Posted by catalina_mike View Post
    Modbus is kind of tricky and some don't follow standards to begin with. I could help you with ALC but you should get a program that allows you to read the raw data and see what the boiler is responding. Getting some to work is a good start and tells you you are setup correctly wiring wise at least. Also some manufactures will not allow you to write to them. Really not sure without seeing the manufactures data. Sorry....
    Here is the manual if it helps...modbus towards the back.

  8. #8
    Join Date
    Dec 2005
    Location
    California
    Posts
    338
    Quote Originally Posted by jaceski View Post
    Anyone get these resolved?
    I have the same issues with those points.

    I mapped the supply temp as Numeric Bit point as Hex 0 with
    Beginning Bit 0 and number of bits 8 then I did the conversion and it works.
    Also, I figured out the CH setpoint and DHW setpoint but
    I get a write error when I try to write to them.

    Low Water is always in alarm, switching it didn't help.
    Boiler High,Med,Low runtimes (hours) not working.

    Are these mapped as Numeric Bits Points?
    Read the registers with a third party program. I use Simply Modbus, but free ones are around.
    I've seen countless errors by vendors. After I verify the point is not working with 2 different programs I call.

  9. #9
    Join Date
    Jan 2012
    Location
    California
    Posts
    92
    Get MBTestPro or something like it and watch the data live. You will be able to see what is being transmitted and what is being sent back from the device. It takes time and is a bunch of playing when you do the first of a certain manufacturer. Its like the quote from the movie I Robot "You must ask the right question" Modbus is exactly that way very funny and far from exact trying to set something up for the first time. Some manufactures also can not take too much data being requested at one time. Then you have big Indian.... aka sometimes the manufacturer will give you the last digit first... lots of trial and error!

  10. #10
    Join Date
    Jan 2008
    Location
    Taxachuesetts
    Posts
    218
    This is a little different then most implementations but not that bad. You need to use Numeric bit point for the analog values (two for each address) with bits 0-7 for the low byte value and 8-15 for the high byte value. Use the enum bit points for the state values.

    Address Byte Type Parameter Name Formula/Data
    0 HIGH State See State Table
    0 LOW Supply Temperature Normal Temperature
    2 HIGH Return Temperature Normal Temperature
    2 LOW DHW Temperature Normal Temperature

    What's strange for me is why then split a byte when there are unused odd numbered registers. Like catalina_mike said lots of trial and error.

  11. #11
    Join Date
    Aug 2012
    Location
    Phoenix, AZ
    Posts
    24
    Quote Originally Posted by krac View Post
    This is a little different then most implementations but not that bad. You need to use Numeric bit point for the analog values (two for each address) with bits 0-7 for the low byte value and 8-15 for the high byte value. Use the enum bit points for the state values.

    Address Byte Type Parameter Name Formula/Data
    0 HIGH State See State Table
    0 LOW Supply Temperature Normal Temperature
    2 HIGH Return Temperature Normal Temperature
    2 LOW DHW Temperature Normal Temperature

    What's strange for me is why then split a byte when there are unused odd numbered registers. Like catalina_mike said lots of trial and error.

    Thanks for the feedback...I built out the temp points as Numeric bits and beginning bit 0 and number of bits 8 for Low Bytes
    and Numeric bits and beginning bit 8 and number of bits 8 for High Bytes with Hex address of 0, 2, etc
    then I performed the conversions.
    What I am trying to do now is write to the setpoints.

    10 HIGH CH Setpoint
    I built Numeric bits writable as Hex address of 10 with Numeric bits beginning bit 8 and number of bits 8.
    I created a preset, but how do I link it?
    It asks for a beginning address but how does the address affect High and Low Bytes with the same address?

    Thanks again!!!

  12. #12
    Join Date
    Jan 2008
    Location
    Taxachuesetts
    Posts
    218
    I built Numeric bits writable as Hex address of 10 with Numeric bits beginning bit 8 and number of bits 8.

    Since you are using Hex 10 is actual 0A, but figure you already have that covered.

  13. #13
    Join Date
    Aug 2012
    Location
    Phoenix, AZ
    Posts
    24
    Quote Originally Posted by krac View Post
    I built Numeric bits writable as Hex address of 10 with Numeric bits beginning bit 8 and number of bits 8.

    Since you are using Hex 10 is actual 0A, but figure you already have that covered.
    Under the point, Did you actually select Hex and put in 10 for address or 0A?

    How do you write to it?

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