help.html


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<h1>Help</h1>
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<h1>Devices</h1>

There is support for 4 devices: Dallas Systems 1-wire temperature sensors (DS), 
pin io (gpio), the Omega relay-expansion board (relayexp), and a MyClock utility device (MyClock). 
The names given here to the devices are used in the Input Variables section.

<h2>DS</h2>
Address - the address for the sensor:
<br>
<pre>cat /sys/devices/w1_bus_master1/w1_master_slaves</pre>

<h2>GPIO</h2>
Address - Enter the pin number being used.

<h2>RelayExp</h2>
Address - Enter the address of the relay.

<h2>MyClock</h2>
Address - leave blank or enter 0


<h1>Input Variables</h1>
<h2>DS</h2>
getTemp - return the devices temperature reading.

<h2>GPIO</h2>
getStatus - Return status of pin.  Either 0 or 1.
<br>
isOn - 1 if pin in high, 0 if pin is low
<br>
isOff - 1 if pin in low, 0 if pin is high
<br>
getMinutesOn - number of minutes the pin has been on
<br>
getMinutesOff - number of minutes the pin has been off
<br>
getTimeOn - miliseconds the pin has been on, 0 if off
<br>
getTimeOff - miliseconds the pin has been off, 0 if on 

<h2>RelayExp</h2>
Same as gpio.

<h2>MyClock</h2>
getTimeStamp - Needed for plotting logged data.

<h1>Evaluated Variables</h1>
Input Variables can be evaluated to be used as triggers for Actions.
<br>
Constant variables can be entered with the value in the Eval column.
<br>
Availiable comparison functions take two arguements. Eg: "gt,1,2" evaluates 1 > 2 and returns false.
<ul>
	<li> gt, a, b : (a > b)</li>
	<li> lt, a, b : (a < b)</li>
	<li> gte, a, b : (a >= b)</li>
	<li> lte, a, b : (a <= b)</li>
	<li> and, a, b : (a && b)</li>
	<li> or, a, b : (a || b)</li>
</ul>

<h1>Actions</h1>
Use an evaluated variable in Name.  When true, the specified device function will be executed.
<br>
<h1>Example</h1>
<img src='control_setup.png'>
<h2>Devices</h2>
The devices are set up with addresses for temperature sensors and the relay address for the Omega2 relay expansion board.
A 'time' device is also made for plotting logged data.


<h2>Input Variables</h2>
The variable 'Time' is case sensitivce for making plots.<br>
Temperatures are measured from both sensor devices.<br>
The state of the relay is stored in two variables for so that the relay is not told to switch on/off if it is already in that state.<br>
The ']' in 'isOn' is used to tell the plotting script to create a separate Y-axis on the right.
(This second Y-axis is hidden for visual simplicity.)<br>
<b>offTime1</b> records the amount of time the relay has been off.

<h2>Evaluated Variables</h2>
Constants <b>warmPt</b> and <b>coolPt</b> are bounds that the freezer should stay between.<br>
<b>offCheck</b> makes sure that the freezer will not cycle too often and burn out the compressor.<br>
<b>beenOff</b> ensures that the relay is off and has been off for long enough.  (This is probably not necessary, but should prevent wierd bugs.)<br>
<b>isWarm</b> - is the temperature beyond the warm setpoint?<br>
<b>isCool</b> - is the temperature beyond the cool setpoint?<br>
<b>off_and_warm</b> and <b>isCool_and_on</b> are the states used to trigger actions.

<h2>Actions</h2>
The relay defined in Devices is turned on or off when all conditions are met.

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