Relay board

[rfeyer]

Having a little information overload in addition to being extremely green at this.
Purchased the WebController in order to automate some Chicken Coop/Run projects, such as automated door opener, turning on/ off fans,e tc
 
I do now understand that I should have a relay which allow control of higher voltaged (24V or 110V) equipment. Actually and initially thought I would be using DtDP relays, but, with all the reading it seems better to use relay boards. Here the problem: which board?
I see in many threads that AZctive High is the way to go, but almost everything seems to be active Low -
This board -SainSmart 4-Channel Relay Module - was mentioned as good by someone, but reading the details on the board seems that is also Active high? Or, I am not understanding the concept yet.
 
Any help would be appreciated,

Rainer

 

[Tschmidt]

The issue about active high vs active low control has to do with what happens during power up. Once the system is up and running it does not matter.
 
If what happens during power up is important then my recommendation is to use hardware to inhibit outputs until the software stabilizes. There are many reset controllers available that can be used to inhibit operation during power up/down. By way of example I'm using a Maxim MAX700 on one of my projects,
http://www.maximintegrated.com/en/datasheet/index.mvp/id/1383
 
If on the other hand your chicken coop project will always stay powered up and in the rare event of a power failure a few seconds of having stuff randomly turned on then ignore it.
 
/tom

 

[CAI_Support]

There are couple on Amazon working great:
 

http://www.amazon.com/Generic-Channel-Module-Expansion-Arduino/dp/B00GGKHVBY

http://www.amazon.com/dp/B00GGKLFXO

 
The 2nd one item title said 24V, but item picture shows relay actually 5V
 
Both are TTL high active.

 

[CAI_Support]

this one is 12V
 

http://www.amazon.com/gp/product/B00GGKHZ7O

 

[rfeyer]

Fantastic! TY both for the choices.
I do have 2 related questions:
1- how do you know these are Active High? I did not read it in the description esp the last two (and this is really for my info so I know in the future)
2- So, this this assumption correct:
    An Active HIGH module will have it's output ON once it receives it's base power (operating power/ board power)
       WebController would have to tell it to be turned off
3- let's use fan example:  Relay is powered on - fan runs - WebController reads temp lower than 80, sends signal to relay and cuts power.
 
Is this above assumption correct, and, are any other items needed to produce the above effect?

Again, am VERY new to electronics. Am searching multiple sites to get base information, but there is a LOT to learn.
If my questions are toooo basic, please let me know
 
Rainer

 

[LarrylLix]

Here is one that requires no hardware from the Webcontrol board, just WEBSET commands. I believe it has many self contained timers and a PLC language of it's own.
 

http://www.digital-loggers.com/din.html

Sorry I have no access to the tools to post a URL properly.

 

[rfeyer]

Thank you for that link, however, I believe this to be my time to start learning Electronics, so, the WebContoller and a relay and hopefully some help with my silly questions should get me started in the right direction. I found a teaching website, though asking for $35.00 per month - a little steep maybe.
The above questions still stand, though.

 

[LarrylLix]

This relay unit came up due to people using the Insteon modules (and other systems) finding their garage doors open when they get home after power failures. I am told by some of the real experts that this unit remembers where it is put though a power failure.
 
The contact capabilities are quite impressive, especially for high voltage DC. Not many can handle over 12vdc.

 

[CAI_Support]

rfeyer,
 
1) To make sure this relay works as TTL active drive the relay on, we purchased one and tested it.
 
There are a lot of relay modules out there has built-in web servers, but WebControl has PLC engine that is unique.
Through PLC engine, users can use different sensors over I2C and SPI bus, along with 1-wire temp sensors, TTL level input, analog input, to make decision how to control output based on your own setup.  It can also send email alert as well as through WEBSET control those http enabled relay modules or notify other controllers.
 
2) Webcontrol TTL output ON will send signal to the relay board to turn on its output, when TTL output is OFF, it will turn off the active high relay board.
 
3) a simple PLC program will let you turn on or off TTL output.  In the user guide chapter six, there are a lot of tested examples you can play with.  Basically, say you have one DS18B20 temp sensor, you set it up through GUI as T1, at 80F, it will reads 800 in PLC, so that you can compare T1 greater than 800, then turn the related TTL output off in PLC. 
 
To reduce constantly ON and OFF, for 80 ON and < 80 OFF--you will find relay ON and OFF a lot, normally in real application, you set a range to turn it ON at 80, but turn it OFF maybe at 79 or lower, depends on your setup.

 

[rfeyer]

Very helpful - I already have gone through WebControl manual and have played with the board a bit. Now I wish to purchase a relay for the above example (starting a fan or something more votaged like a 110V gadget). As mentioned, my research came up with the following questions, still needing answers:
1- how do you know these are Active High? I did not read it in the description esp the last two (and this is really for my info so I know in the future)
2- So, this this assumption correct:
    An Active HIGH module will have it's output ON once it receives it's base power (operating power/ board power)
       WebController would have to tell it to be turned off
 
TY again in advance,

Rainer

 

[rfeyer]

Also, forgot to clarify - you said you tested the above board - was the outcome good or bad?

 

[CAI_Support]

We tested means that we tested working correctly. They are active with TTL ON.  During power recycle, they do not turn on and off by power or WebControl reboot. They only turn on when WC output TTL HIGH.
 
Since we have no connection with the seller, we can not guarantee all their future shipment will not change.

 

[rfeyer]

Thank you again - now I understand.
 
Rainer