[Stoves] Digital Scale Capture programme for stove testers

Wed Dec 15 10:11:03 CST 2010

Dear Friends

In the message titled TLUD as a lighting technique for coal stoves there is
attached a photo of the real time outputs from a test of the GTZ 7.4
crossdraft coal stove. 

It shows two computer screens with the temperatures on the left.

On the right screen is a grey block with two graphs. The block is a scale
reading programme which is available free to anyone for personal use and is
well suited to stove development. 

Apart from reading the scale, it has simultaneous graphing capabilities. On
the top graph the blue line (curve) is the kW output in real time. Also
shown is a nearly straight line which is the rate at which the mass burned
changes. Note that it is basically a straight line meaning that the power
output is constant. This is the advantage given by stoves that burn TLUD,
crossdraft and downdraft: continuous heat generation.

The spaghetti underneath is the instantaneous mass burn rate as recorded by
the scale. It is auto-scaling so it looks noisier than it actually is.

The programme was mostly written by Jeremy Pemberton-Pigott (Agilent,
Singapore). It can be configured in many ways to provide real time
measurements and includes auto-saved CSV files, prepend naming and
un-losable data because it writes to disk for each reading. The file can be
copied during recording and the copy opened if desired. It auto-appends the
date and time of the start of saving data and places it in a predefined
location. It will work in MS operating systems up to Windows 7 (which we use
at SEET in UB as do James and Vinny at the SeTAR Centre in Johannesburg).

It can read any scale that can transmit data continuously over a COM cable
(RS-232). The reading rate depends on the speed of the CPU and the COM port.
With an Edgeport USB-COM adaptor and an i7 processor it can receive 1 scale
measurement per 10 milliseconds.  An i5 runs at about a reading per 20
milliseconds. The data stream can either be sampled for 'n' readings or
continuously averaged for the measurement period (we use 10 seconds to limit
the data set size). Data sets can be summed for a print to screen of the
rate of change (which we set to once per minute). This appears on the right
column of the grey block.

Entering the LHV as received (LHV-AR) of the fuel allows the simultaneous
calculation of the stove power and its display on a chart with an
auto-ranging axis.

It is fully configurable for serial communication. It can also capture
incoming data to find out exactly what text/numbers are arriving and which
needs to be stripped from the numbers of interest. The info not needed
(non-numbers) is stripped by entering the unwanted info in REGEX format on
the CONFIG tab. It has a random number generator to test settings and
displays the duration of the test and the number of readings saved on the
main tab.

There is a developers version for capturing crashes or misbehaviour. The
current version is 1.74 and is available by email from me. It will arrive on
the form of a .bin file which you save and rename to an .exe file.

Regards

Crispin

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