Guidelines When Using the RCSGuidelines When Using the RCS
Once the RCS is properly installed, the system conditioned and calibrated, the following guidelines should be maintained during standard experimental operation.
Verify that the RCS switch is set to EVENT on the RCS unit. To turn on the RCS, select Event/On from the Control menu. See Adjusting the Event, Storage, Gas, and Air Cool Selections.
A dry, moisture-free gas source is required as the base purge when using the RCS, in addition to the standard purge gas. Dry nitrogen is recommended for this purge. These gases must remain on continuously. If they do not, the atmospheric moisture will enter and contaminate the system.
Access the Tools/Instrument Preferences/Cooler Page of the DSC instrument control software. Verify that the correct cooler type (RCS 40 or RCS 90) is selected, check Leave RCS on.
Check Activate secondary purge when lid is opened (RCS and LNCS only), if desired. The RCS Purge will automatically turn on whenever the cell is opened by the AutoLid. (NOTE: This feature is not applicable to DSC instruments that have manual lids.) It is strongly recommended that the cell lids be in place anytime that a sample is not being actively loaded or unloaded.
Select Tools/Instrument Preferences/DSC page of the DSC instrument control software and verify the desired Standby Temperature.
If you have an Autosampler, select Tools/Instrument Preferences/Autosampler page and clear the RCS (Event) Off box (leave box blank) as a sequence stop option. This will allow the RCS event function to operate. NOTE: Autosampler sequence stop options are invoked even for a one run sequence when the Autosampler is enabled.
When setting up experiments, be sure to verify the post-test conditions. The temperature window should be enabled and a temperature range above ambient should be used to prevent the cell from cooling down between experiments.
When setting up an Autosampler sequence, access the Instrument Preferences/Autosampler Page and select the desired sequence-end option for the RCS. NOTE: Autosampler sequence stop options are invoked even for a one run sequence when the Autosampler is enabled.
DO NOT open the DSC cell at below ambient temperatures.
Once the DSC-RCS system has been conditioned, DO NOT turn off the RCS unless the system will not be used for an extended period of time (for more than 2 or 3 days). It is recommended that you do NOT turn off the RCS between runs or for overnight periods for optimal performance.
Operating without an effective base purge, allowing the cell to remain at the lower temperature limit without heater power (e.g., without post-test conditions) for extended periods of time, and/or removing the RCS from the cell when the flange temperature is below ambient can result in excessive moisture in the cell and requires extended conditions for drying such as performing Step 1 of the conditioning procedure. See Cell/Cooler Conditioning. In those cases, the system must be dried for much longer times.
WARNING: Do not exceed 100°C with the RCS cooling head installed and the RCS power off. Serious damage and/or injury could occur.
CAUTION: We recommend that you do not use the RCS when running isothermal experiments above 400°C. Damage to the unit can occur if used at high temperatures for extended periods.
NOTE: Once the cooling flange reaches operating temperature (–90°C), it condenses any moisture present. If the initial moisture level is too high, or if the atmosphere moisture subsequently entering the cooling head enclosure is not minimized, then artifacts can be observed in the heat flow signals. Typically, but not exclusively, the artifacts are observed between 0 and 100°C, which increase in intensity over time.
