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Thread: BMS points for electrical equipment

  1. #1
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    BMS points for electrical equipment

    I am an electrical engineer and I don't have much information about BMS,

    My question with regard to the required i/o points for electrical equipment, there are different information shall be forwarded to BMS such as:
    - On status.
    - Off status.
    - Trip.
    - fault.
    - control...etc.

    For each of the above, do we need a separate point from BMS or it can be combined together?
    "Would that work !!!"

    Sleem

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    190401-0739 EDT

    m sleem:

    When I read your post I had no idea what you were talking about. Doing a search on BMS brought up Building Management System. That solved I still don't know what an "i/o point" or "point" is.

    I would classify on and off as one point, a binary signal. Control would be one point, but could be be either binary, multi-bit digital (x number of wires), or analog. Further it could be a multi-level digital signal, for example 3 state, +, -, 0. These I would also call a point from a system perspective.

    But I could multiplex several of these together and transfer that data over a single path, that might be called a point. For example, current, voltage, and power to one device like a motor.

    .

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    On and off could also be two points.

    .

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    From what I remember from seeing BMS points, I believe you will have to have separate points with each point having an I/O state.

    status - On/Off

    Trip - I/O.

    Fault - common or itemized?

    control...etc.

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    You need to clarify them what you give to BMS - for example dry contact or 24V. What you give them is input into BMS program. If you give voltless contact (on/off) it's 1 input into BMS

    Sent from my ONEPLUS A6013 using Tapatalk

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    Unless otherwise specified, I always furnished "open when active" to a BMS input and requested the same from their output (had never heard the term BMS then). This provided positive inputs and outputs. Also preferred 4-state supervision, if their equipment would do it.

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    Quote Originally Posted by m sleem View Post
    My question with regard to the required i/o points for electrical equipment, there are different information shall be forwarded to BMS such as:
    - On status.
    - Off status.
    - Trip.
    - fault.
    - control...etc.

    For each of the above, do we need a separate point from BMS or it can be combined together?
    It depends on the BMS and how you want to control the equipment. A simple fan unit could have one output point for "run" (on/off) and one input for "running" (aux contact on the contactor or a current sensor). Might add another reading a pressure differential sensor across the fan (on/off or analog/proportional).

    I don't know of a situation where you could, or should, "combine" points.

    Other than just learning, this is really question for the HVAC and BMS engineers.

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    Quote Originally Posted by gar View Post
    190401-0739 EDT

    m sleem:

    When I read your post I had no idea what you were talking about. Doing a search on BMS brought up Building Management System. That solved I still don't know what an "i/o point" or "point" is.

    I would classify on and off as one point, a binary signal. Control would be one point, but could be be either binary, multi-bit digital (x number of wires), or analog. Further it could be a multi-level digital signal, for example 3 state, +, -, 0. These I would also call a point from a system perspective.

    But I could multiplex several of these together and transfer that data over a single path, that might be called a point. For example, current, voltage, and power to one device like a motor.

    .
    I was thinking Burner Management System?

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    BMS

    https://www.google.com/search?source...10.l9lcx40ZOag

    Most of the BMS systems we encounter in buildings receive a dry contact. whether open or closed, as a monitoring point.
    For example, where multiple automatic transfer switches (ATSs) are employed, one contact indicates switch position: either normal or emergency. Another contact indicates sources available: normal and emergency. Another: generator running, and so on. These contacts are usually auxiliary contacts (micro switches) that operate by the switching mechanism or from the contact of an auxiliary relay. The PC (BMS) has a program to display a mimic panel or diagram showing the status of all ATSs in the system.
    The BMS can also send a control signal (dry contact or voltage) to remotely test the ATS by simulating a power failure and transfer the switch to the generator.
    Another name for similar systems is called Supervisory Control and Data Acquisition: SCADA. Google it.
    Ifyoucan'texplain itsimply youdon'tunderrstanditwellenough- Albert Einstein

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    So for I/O (input/output) there are several types of points.

    Digital inputs
    Digital outputs
    Analog inputs
    Analog outputs

    A digital output (DO) is a dry contact on a controller. It can have a voltage put through it to enable things.

    A digital input (DI) is looking for an on/off like status from a motor.

    An analog input (AI) also called a universal input (UI) is looking for an analog voltage, typically either a 4-20ma signal or a 0-10v signal.

    Finally an analog output (AO) is an incoming signal similar to a AI that can be used for feedback like a positioning signal from an actuator or a temperature signal from a thermistor.

    Each of these individual things are typically called points. So 3 DI's and 2 AO's would be 5 points. While this is a really simplified primer, there is an incredible wealth of info available on the internet.
    The world is round, you will get there no matter what path you take.

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