Difference between revisions of "Heating experiment"
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Latest revision as of 16:33, 30 July 2010
This page documents the heating dynamics experiment in the 3rd year labs. It is used as one of the experiments for the Process Dynamics (CPN 321) component of Laboratory (CLB 321). This experimental setup is also used for some Thermodynamics experiments. The sections below lists the equipment currently in use, and links to software/manuals concerned with the setup.
Hardware
Experimental setup
The experimental setup only consists of two thermocouples connected to a PC via temperature transmitters. The rest of the experiment is set up as required (e.g. a kettle is boiled and the temperature measured to determine its dynamics).
Instruments/Devices
The following instruments and devices are used to the heating dynamics experiment;
| Instrument/Device | Signal/Connection | Notes |
|---|---|---|
| 2x Thermocouples | Connected to temperature transmitters | |
| 2x Temperature transmitters | Connected via RS-232 (serial) to PC | Manual |
Software
The temperature transmitters are connected to the PC using standard RS-232 (serial) connections. Therefore, the connection protocol needs to be manually configured. The default (working) settings for the two units are displayed below. Note that they can be programmed to use different settings (consult the manual for instructions).
- Baud: 9600 bits per second
- Data bits: 8
- Parity: None
- Stop bits: 1
- Flow control: None / Xon Xoff
The units do not supply data in a continuous stream, and needs to be prompted for data. The command to send to a unit to request a reading is;
TA$
Windmill (a free-ware serial communication application) is used for serial communication and data logging. The units are set up using ConfIML is used to configure the units, their channels and data parsing (see below). SetupIML is then used to generate an instrument data file, which specifies the names, units and scaling of the channels. Finally, Logger is used to read data and save it to file.
A point to note is that Windmill does not save the entire data message (received from the unit) to file, it relies on the correct parsing of the message. comDebug (also a Windmill application) can be used to troubleshoot communication to/from the units. Info obtained from comDebug identifies the data message received from the units as 14 byte message, with 8 blank bytes, 4 data bytes and 2 trailing bytes for a carriage return and newline. A sufficient parsing string (to be used when setting up the units in SetupIML) is to ignore the first 8 bytes and then extract data until the carriage return. Thus,
\I08\E"\C013"
The software used is available here;
- Windmill installation files
- comDebug installation files
- Pre-configured instrument data files
- PCI Serial Port drivers (just in case)
Since 2010, Matlab is no longer used for this experimental setup. However, the .m code for serial communication for this setup is available here.
