Controlling CTS Environmental Test Chambers.

Engineers often ask these common questions:

• “How do I control the chamber?”
• "What options are there to control the chamber?”
• “Can I integrate the chamber control with the automated test/diagnostic system developed for my product?”
• “What format can I extract the results in?”

Controlling a CTS chamber is very straightforward! There are two basic ways to control the chamber with additional choices.
1. Control from the integrated colour touch screen with the following (but certainly not exhaustive) list of functions.
a. Manual control of temperature and if the machine is a “C” version also the humidity.
i. Set points and “actual” figures are displayed.
ii. Status of the chamber is displayed.
iii. Other key criteria are displayed e.g. water tank level on “C” machines.
iv. Viewing of trend graph.
v. Viewing of numerous options and settings.
vi. Creation, storage, revision, retrieval and running of multiple test profiles.
vii. Password control if required at various levels for key functions.
b. Automated control to run previously saved test profiles.

2. Remote control not using the chamber keypad but instead a linked external device to achieve all of the functions in 1 above. Systems can be connected through the following comms ports with the right software present (see 3 below).
a. RS232. This is a legacy standard and is often available on external systems designed for industrial applications. The RS232 standard is well defined established and stable.
b. Ethernet. This allows chamber control from any Ethernet connection. Again this standard is reasonably well defined and stable.
c. USB. This standard is not so well defined and has been subject to revisions in recent years. For environmental chamber control it means using an RS232/USB converter module will only work reliably with certain types of converter as they all have some conversion process not all of which are the same.
d. RS485. This standard does allow daisy chain control of CTS chambers, however it is not commonly used but is available if required.

3. Suitable software for remote control.
i. CTS CID Pro software. This gives full control of the chamber and provides trend graph graphics all on a PC platform. There is no Apple version. CID Pro can control multiple chambers and for most options the software license is on a USB dongle. The software is a free download and can be used in demo mode if a dongle is not present which is required to run a chamber. CID Pro can be used on all forms of the comms ports available. There are a few versions available for Ethernet networked vs direct connection etc.
ii. Any external software capable of sending and receiving ASCII data. This data is a fundamental well established core data set used extensively in electronics communications. The character sets and formats are usually well known to electronics engineers and we provide free downloads of the command/read/write structure. This ASCII comms format is usually used by clients with their own test systems.
iii. Suitable commercially available software may have comms abilities that with interface with a CTS chamber. E.g. Labview® has this ability as do a number of other systems.

4. Data extraction.
a. Extracted/downloaded data from the chamber would be in CSV (basic spreadsheet) format. Data will include setpoints and actual figures, timebase data, the status of volt free contacts and if fitted the digital and/or analogue controlled outputs. The CTS CID pro software makes extracting data very easy. Extraction of data by other comms is not difficult but somewhat depends on what software is connected to the chamber.

b. Extracted data can also include machine performance diagnostics which can be used by our service team to analyse machine performance and non user settings.

Final notes.
• Some remote functions are excluded for safety reasons typically to prevent a remote operator from putting at risk personnel who may be at the machine e.g. you can’t turn on the refrigeration or heating with the door open and without an acceptance at the machine.
• CTS test profiles can be saved and transferred to other similar CTS machines.
• The CTS colour touch screen controller can be understood and the machine used usually within an hour, as users become more experienced they will find access to more complex functions as they require them.
• In 2015 CTS touch screen control panels will change from “resistive” technology to “capacitive” for new chambers. This brings more subtle control input and 4 x screen resolution allowing better trend graphs (newer screen shown on left) as well as other benefits.

If you have questions about controlling a CTS chamber please contact us.
info@qtpe.co.uk