Amphenol Kaye CTR-40, User Manual, Page: 69 / 84

9 Digital Communication Interface
58
command. A command may be used to either set a parameter or display a pa-
rameter depending on whether or not a value is sent with the command follow-
ing a “=” character. For example an “s” <cr> returns the current set-point and
an “s=50.00" <cr> sets the set-point to 50.00 degrees.
In the list of commands, characters or data within brackets, “[” and “]”, are op-
tional for the command. A slash, “/”, denotes alternate characters or data. Nu-
meric data, denoted by “n”, may be entered in decimal or exponential notation.
Characters are shown in lower case although upper case may be used. Spaces
may be added within command strings and will simply be ignored. Backspace
(BS, ASCII 8) may be used to erase the previous character. A terminating CR is
implied with all commands.
9.3 Cooling Control
The CTR –40 bath has a fully automated refrigeration control system when the
cooling power switch on the front panel is activated. Under normal conditions,
the refrigeration is on at any temperature below approximately 60°C (see Sec-
tion 7.6, Refrigeration). When the bath is controlling at temperatures between
0°C and 60°C, the refrigeration is in the hot gas bypass or reduced cooling
mode. Below 0°C the refrigeration is in the high cooling mode, the hot gas by-
pass is turned off automatically. When the bath is cooling from one temperature
to another below 60°C, cooling is at maximum until the bath is within 1 degree
C of the set-point. These conditions are the default conditions but may be al-
tered in the following ways.
•
The cooling (refrigeration) may be set to operate in the auto, on, or off
modes. See Section 8.13.2, Cooling Mode.
•
The hot gas bypass or reduced cooling mode may also be set to on, off, or
auto.
The “auto” modes allow the bath to operate automatically in the manner de-
scribed above. The cooling “on” function eliminates this auto feature and the
refrigeration is on at all times unless the front panel switch is turned off or until
some other menu selection is made. The hot gas bypass mode selection works
the same way. The “auto” function is the default and active until off or on is se-
lected. “On” means it is always on with no automatic selection and “off” is al-
ways off (or cooling always on maximum). It may desirable for different
reasons to eliminate the automatic functioning; therefore, these selections are
made available either through the front panel or through the digital communica-
tions interface.