BMS points for electrical equipment

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m sleem

Senior Member
Location
Cairo
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?
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
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.

.
 

Chamuit

Grumpy Old Man
Location
Texas
Occupation
Electrician
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.
 

victor.cherkashi

Senior Member
Location
NYC, NY
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
 

GrayHair

Senior Member
Location
Nashville, TN
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.
 
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.
 

MrJLH

Senior Member
Location
CO
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?
 

ATSman

ATSman
Location
San Francisco Bay Area
Occupation
Electrical Engineer/ Electrical Testing & Controls
BMS

BMS

https://www.google.com/search?sourc.....gws-wiz.....6..35i39j0i131j0i10.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.
 

rlundsrud

Senior Member
Location
chicago, il, USA
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.
 

rlundsrud

Senior Member
Location
chicago, il, USA
Apologies, I noticed my mistake on the AI point and tried to edit it but i accidentally created a new post. Please attempt to ignore my previous post.

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. It can also be used for feedback like a positioning signal from an actuator or a temperature signal from a thermistor.

Finally an analog output (AO) is an outgoing signal similar to a AI in terms of voltage current values. It is used for things like controlling an actuator or sending a speed signal to a VFD.

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.
 
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