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##### Activity
• Jan 23 01:51
ChristianTremblay opened #314
• Jan 22 22:00

ChristianTremblay on develop

Mostly adding some details in l… (compare)

• Jan 21 02:14

ChristianTremblay on develop

Change the binary and multistat… Update float to int type Merge pull request #313 from ku… (compare)

• Jan 21 02:14
ChristianTremblay closed #313
• Jan 20 05:21
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• Jan 20 04:35
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• Jan 20 03:59
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• Jan 20 03:44
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• Jan 18 17:37
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• Jan 18 17:33
kushan-26 opened #313
• Jan 18 05:22
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• Jan 18 03:03
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• Jan 17 22:35
kushan-26 opened #312
• Jan 15 04:08
kushan-26 commented #310
• Jan 14 21:58
ChristianTremblay commented #310
• Jan 14 17:36
kushan-26 commented #310
Christian Tremblay
@ChristianTremblay
@bbartling I played around with it this weekend and this is a challenge. You can look where I am if you check the latest master branch... it's not perfect as I still have some troubles dealing with SI and imperial units... You must know that reverting wet buld or dewpoint to get humidity leads to some errors as the formulas I found were all approximations.... but still a fun trip
from ddcmath.psychrometric import Psychrometric

In [5]: e = Psychrometric(temperature=25, humidity=50, SI=True)
25.00 degree_Celsius 50.00 percent
25.00 degree_Celsius 50.00 percent

In [6]: e
Out[6]: T: 25.00 degree_Celsius | H: 50.00 percent | DP: 13.86 degree_Celsius | WET: 18.00 degree_Celsius -> Enthalpy: 68.14 kilojoule / kilogram
e = Psychrometric(temperature=25, wetbulb=18, SI=True)
25.00 degree_Celsius 50.05 percent
25.00 degree_Celsius 50.05 percent

In [8]: e
Out[8]: T: 25.00 degree_Celsius | H: 50.05 percent | DP: 13.87 degree_Celsius | WET: 18.00 degree_Celsius -> Enthalpy: 68.17 kilojoule / kilogram
 e = Psychrometric(temperature=25, dewpoint=13.9, SI=True)
13.90 degree_Celsius 25.00 degree_Celsius
13.90 degree_Celsius 25.00 degree_Celsius

In [10]: e
Out[10]: T: 25.00 degree_Celsius | H: 50.11 percent | DP: 13.90 degree_Celsius | WET: 18.01 degree_Celsius -> Enthalpy: 68.20 kilojoule / kilogram
Christian Tremblay
@ChristianTremblay
This can also be of interest : https://unidata.github.io/MetPy/latest/index.html
But there are dependencies like ScikitLearn, numpy, etc...
Ben Bartling
@bbartling
Thanks for this stuff @ChristianTremblay its super helpful...
gjaehrling
@gjaehrling
HI Christian, I hope this channel is still alive. I'm struggeling with the following task. I need to fetch (extract or read) values from Building Control devices that are managed by a BacNET server. We are within one VPN and the analytical application (for example for anomaly detection) is on a different server. A simple illustraction is the one in thread above
Whatever I do, I'm not able to see any devices routing tables or alike. Maybe I'm missing here something fundamental
We only need to read the messages
Christian Tremblay
@ChristianTremblay
Is the BACnet server a BBMD ?
Just to be sure, add the subnet to your local IP (ex. 10.0.0.34/24)
If the points are in the BACnet server… use a device
bs=BAC0.device(“10.0.20.30”, deviceinstance, bacnet)
You need to know the device instance
Ricardo G
Matvey
@mtovts
Hi everyone! I have a question about COV. Can I unsubscribe? I found the cancel_cov method in the CoV mixin, but I continue to receive notifications after it is called. How’s that supposed to work?
Christian Tremblay
@ChristianTremblay
@rigavi_twitter Can you try using BAC0.lite instead of connect ?
@mtovts
dev['point'].subscribe_cov()
dev['point'].cancel_cov()
Christian Tremblay
@ChristianTremblay
@mtovts : I think I saw what you are talking about.... a subscription made in the past... cancelled.... and I still receive COV notifications.
I'll have to investigate, let me know if you find something on your side.
Ben Bartling
@bbartling

How do you ovrride an BO with BAC0? When I read the BO is comes thru as active

If I run:

import BAC0, time, random

bacnet = BAC0.lite()

object_type = 'binaryOutput'
object_instance = '1'
value = 'False'

print("check ",check)

write_vals = f'{address} {object_type} {object_instance} presentValue {value}'
print("Excecuting write_vals statement:", write_vals)

write_result = bacnet.write(write_vals)

print("check ",check)

bacnet.disconnect()
print('BACnet disconnected')

I cant get to the end of the code it doesnt like what I am trying to write.

check  active
Excecuting write_vals statement: 12345:2 binaryOutput 1 presentValue False
Ben Bartling
@bbartling
Ah, I had to google whats the opposite of active using value = 'inactive' works
Christian Tremblay
@ChristianTremblay
:-)
John Jensen
@jensenja
hi all. trying to figure out where i'm going wrong. i have an instance of ALC that i'm doing testing with. I'm having ALC subscribe to an Analog Value that I'm creating within BAC0 in order for BAC0 to send out CoV notifications for.
it works, but only if the controller doing the subscribing is on the same subnet as the machine running BAC0
I thought that I'd have to tell BAC0 to connect to a BBMD using connect(), but when I do this, I'm no longer able to add analog values to BAC0 using add_objects_to_application()
I get this error
Traceback (most recent call last):
File "/root/bacnet/./test_cov.py", line 49, in <module>
main()
File "/root/bacnet/./test_cov.py", line 41, in main
initialize_objects(bacnet_device)
File "/root/bacnet/./test_cov.py", line 25, in initialize_objects
File "/usr/local/lib/python3.10/site-packages/BAC0/core/devices/local/object.py", line 186, in add_objects_to_application
raise TypeError("Provide BAC0Application object or BAC0 Base instance")
TypeError: Provide BAC0Application object or BAC0 Base instance
John Jensen
@jensenja
here's the full code
#!/usr/bin/env python

import BAC0
from BAC0.core.devices.local.models import analog_value
import logging
import random
import sys
import time

logging.basicConfig(
stream=sys.stderr,
level=logging.DEBUG,
format='%(asctime)s %(name)-12s %(levelname)-8s %(message)s'
)

log = logging.getLogger(__name__)

def initialize_objects(bacdev):
_new_objects = analog_value(
name='a_test_point',
presentValue=0
)

def update_values(bacdev):
i = random.randint(1, 65535)
log.debug('setting new value of a_test_point to {}'.format(i))
bacdev['a_test_point'].presentValue = i

def main():
#BAC0.log_level('silence')
#bacnet_device = BAC0.lite(deviceId=4169000, localObjName='cov_test')
#for i in dir(bacnet_device):
#    print(i)
#print(type(bacnet_device))
initialize_objects(bacnet_device)
#while True:
#pass
#update_values(bacnet_device)
#time.sleep(32)

if __name__ == "__main__":
main()
if I basically comment out the call to connect() and uncomment everything else, it works fine, but again only if the controller doing the subscribing is on the same subnet (10.15.4.0/24) as the BAC0 device.
John Jensen
@jensenja
what i'm really not understanding is that if i do print(type(bacnet_device)) for each invocation of BAC0, they're both showing the exact same thing: <class 'BAC0.scripts.Lite.Lite'>
John Jensen
@jensenja
just as an FYI on the last messages, we're going to make sure that our existing BBMD's are functioning the way they should - my building engineer doesn't believe that BAC0 should be registering as a foreign device in order for the subscriptions to work
Christian Tremblay
@ChristianTremblay
@jensenja good catch.. if the app was defined as foreign device or BBMD, it failed... it is now fixed in the develop branch
John Jensen
@jensenja
hey thanks @ChristianTremblay! I'm not sure if this will solve our problem (myself and the other guy are now questioning if subscriptions were ever intended to cross subnet boundaries) but I'll check this out and give it a test!
Christian Tremblay
@ChristianTremblay
If your network is setup properly, and device 1 sees device 2, cov will work.
Safrone
@Safrone
Hey yall, trying to discover some bacnet devices and didn't have any luck. Sometimes this is because we have our device on the wrong subnet so I did some wireshark sniffing. Usually I'm able to use the output to find the broadcast IP to figure out what mask I should be using for the subnet to fix things but I got some different looking output
Does anyone have experience with this kind of messaging? I've never seen the source/destination look like Mac addresses so I'm not sure what to test out here
Joel Bender
@JoelBender
Please expand one of the packets to look at the layers, you are probably dealing with BACnet over Ethernet.
Safrone
@Safrone
that does look like it
just surprised I'm able to see it then via wireshark. IDK the best way to initiate discovery given this
Joel Bender
@JoelBender
Next two octets after the length are probably X’82’, check out the hex piece.
You’ll need some IPv4-to-Ethernet BACnet router. I bet one of the devices is already doing that.
Safrone
@Safrone
yup
Safrone
@Safrone
@JoelBender Would this require specific hardware or is there a script that would enable this. I didn't see any responses to my ipv4 discovery requests so probably will need some talking to the client
Joel Bender
@JoelBender
It looks like you are talking to a device from Delta Controls and since it speaks BACnet/Ethernet, unless it is a very old device, it also speaks BACnet/IPv4. The simplest thing to do would be to configure it with BACnet/IPv4 support turned on, give the new port a BACnet network numbers that don't conflict with other BACnet network numbers in the intranet, and you're good to go.