This example shows how to access the Valden Heat Pump data from your server, Raspberry Pi, and so on.
All you need is a USB->RS485 converter and python2 installed.
Connect your computer to RS485 line as pictured below, connect another side of wire like described at Valden Display page and run python script from an example below.
Remember, RS485 is a 3-wire line. Do not use cheap converters without "signal ground" and with only A and B. They'll work for a few meters distances.
# Communication example for:
# - Valden Display https://github.com/openhp/Display/
# - Valden Service Display https://github.com/openhp/ServiceDisplay/
#
# The source code licensed under GPLv3.
#
# This product is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
# without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the GNU General Public License for more details.
import serial
from time import sleep
import datetime
import string
import sys
#-------------------------------------------------------
#function to send commands and print answers
def SendCommand(ID_to, command):
#send command
towrite = str(ID) + str(ID_to) + command
print "> " + str(datetime.datetime.now())[0:19] + " we sent: " + towrite
try:
serial.write(towrite)
except: #do not catch all exceptions in a real code
print "USB>Serial converter disconnected?", sys.exc_info()
line = None
return 0
#read result
try:
line = serial.readline() # read a '\n' terminated line
except: #do not catch all exceptions in a real code
print "USB>Serial converter disconnected?", sys.exc_info()
line = None
return 0
#print answer
if len(line) > 2:
print "< " + str(datetime.datetime.now())[0:19] + " we got: "+ line
else:
print "No answer from", ID_to, "\t\t", str(datetime.datetime.now())[0:19]
#-------------------------------------------------------
#open serial
print "Starting.."
try:
serial = serial.Serial('/dev/ttyUSB2', 9600, timeout=3) #Change serial name to yours!
print "Opened: ", serial.name
except serial.serialutil.SerialException:
print "Serial open error! Change serial name to yours! (ex: /dev/ttyUSB5, or something like COM9 at win)"
exit (0)
#-------------------------------------------------------
#some example values
eev_target = "02.50" #new eev temperature difference
newtemp = "31.50" #new setpoint temperature
ID = chr(0x30) #this script ID, 0x30 by default, default value supported by all Valden components so do not change it
remote_ID = chr(0x41) #Remote Display ID ( this display https://github.com/openhp/Display/ or that display https://github.com/openhp/ServiceDisplay/ )
#Remote Display ID can be changed, and yes: few devices with unique IDs can work together at the same time at same line
#-------------------------------------------------------
#example cycle, interaction with Remote Display
#commands:
#(G)et all
#new (T)emperature set (setpoint)
#new (E)EV difference set
#cycle sends 10 times (G)er all command
#then sends (T)emperature set
#then sends (E)EV difference set
#then cycle
while ( 1 == 1):
for i in xrange (10):
SendCommand(remote_ID,"G") #sends 0AG : from ID 0 to ID A (G)et all
sleep (5)
SendCommand(remote_ID,"T" + newtemp) #sends 0AT31.50, command format TNN.NN
sleep (5)
SendCommand(remote_ID,"E" + eev_target) #sends 0AE02.50, command format ENN.NN
sleep (5)Script output example (click to enlarge):
Short names (keys) specific for JSON communication:
| Abbr. | Full name |
|---|---|
| A1 | setpoint |
| E1 | error code |
| HPC | Heat Pump connected (to remote display, 1=yes, 0=no) |
| W1 | Watts |
All abbreviations and status messages you'll see at the display are listed at the Valden Heat Pump Controller appendix. Error codes also there.
What's next? You have all information you need to integrate, for example, with Home Assistant or another "Smart Home" system you like. Just parse gotten strings (that's very easy in a python) and feed key-value pairs to your favorite system.
I do not use "smart home" systems, but I like graphs. Graphs help to analyze processes dynamics. So, I have a script (much more complicated script) on the server side, that get stats from all of my devices and draw graphs for me.
For example, daily graph for one of my Heat Pumps (click to enlarge):
To get graphs you can use something like Cacti monitoring system.
And one more: you can use "set temperature" commands to automatically change "setpoint" temperature to create a comfortable balance between power saving and house temperature. Or day-dependent, hour-dependent or something-else temperature dependent system.
© 2015-2021 D.A.A. All rights reserved; gonzho AT web.de; https://github.com/openhp/HP-integration-example/.
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Attribution: You must clearly attribute Valden Heat Pump integration (https://github.com/openhp/HP-integration-example/) original work in any derivative works.
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The source code licensed under GPLv3.
This product is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
For third-party libraries licenses used in this product please refer to those libraries.
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