Filename: README
Author: Weiyang Wang <wew168@ucsd.edu>

This python script attempts to implement a controller of for the
cryomech CP-2800/CP-1000 controller. Detailed implantation/documents 
are in the pt415.py file. The module is developed under python2.

Warning / error output will be directed to stderr. There is a debug
flag in the script (DEBUG = False) which if turned on, will make the
output very verbose (although debug output is also directed to stderr).

For a simple run, just load the script by

bash4.2$ python -i pt415.py

which would load the entire script in the interpretor. For more 
complicated uses please use import. 

To initiate a controller run

>>> d = PT415("/dev/ttyXXXX"") 

where the argument is the address of the serial port that the CP1000/2800 
is on. Other arguments such as baudrate/timeout can also be specified.

To start/stop the controller, run 

>>> d.start()
>>> d.stop()

To read the status/runtime of the controller, run

>>> d.status()
>>> d.runtime()

There are merely the convenient wrapper provided; for more commands
please check the CP1000/2800 manual and use the proper hashcode/index pair.
For a writing command use 
>>> d.writevar(code, index, vale)
For a reading command use
>>> ret = d.readvar(code, index)

for more detail please check the actual implementation.

A logger function is provided for monitoring the controller. The default
logger will monitor the following entries (in a csv format):
    -Time
    -Unix Time
    -Elapsed time (min)
    -Input H2O Temp (C)
    -Output H2O Temp (C)
    -Helium Temp (C)
    -Oil Temp (C)
    -High Side Pressure (PSIA)
    -Low Side Pressure (PSIA)
the logger function is called "log" and has the following header:
    
    def log(interval = 600, flag = 'w', filename = None)

interval specifies the time interval between two log entries in seconds.

flag is the file opening flag, which should be a string of either 'w' or 'a'.
Under 'w' flag, a new file with @filename will be created (or if @filename is
None, a file with default filename will be created) for logging. If a file 
with the same name already exist, it will be overwritten. 
Under 'a' flag, if the file with @filename already exist, new log entries 
be appended to this file. If the file with filename does not exist or @filename
is None, it will behave the same as a 'w' flag. For a existing file with empty
header line, a new header line will be written.

filename specifies the name of the file that log will be written to.
If it's None, a file with the name "yyyymmddhhmmss.log" with the current
time of log starting will be used.

The log function runs indefinitely until a ctrl-c (SIGINT) signal is caught.

Example:
>>> d.log(1, filename = "run1.log")
will create/overwrite a file named "run1.log" and write entries into it,
with an 1 log/second rate.
>>> d.log(10, 'a'. "run1.log")
will append new logs to "run1.log" with a 6 logs/minute rate
>>> d.log() 
will create a new file "20171208132840.log" (the actual time of me writing this
document) and write logs into it with an 1 log/10minutes rate.