fsc2: 6.10 Temperature Controller Functions

6.10 Temperature Controller Functions

Modules for the following temperature controllers exist:

lakeshore330: Lake Shore 330
itc503: Oxford Instruments ITC503
bvt3000: Bruker BVT3000

To use a module in an experiment put its name into the DEVICES section of the EDL script.

List of temperature controller functions:

`temp_contr_name()'
`temp_contr_temperature()'
`temp_contr_sample_channel()'
`temp_contr_heater_sensor()'
`temp_contr_setpoint()'
`temp_contr_state()'
`temp_contr_heater_state()'
`temp_contr_heater_power()'
`temp_contr_heater_power_limit()'
`temp_contr_check_heater()'
`temp_contr_gas_flow()'
`temp_contr_tune_state()'
`temp_contr_proportional_band()'
`temp_contr_integral_time()'
`temp_contr_derivative_time()'
`temp_contr_cutbacks()'
`temp_contr_adaptive_tune_trigger()'
`temp_contr_ln2_heater_state()'
`temp_contr_ln2_heater_power()'
`temp_contr_check_ln2_heater()'
`temp_contr_lock_keyboard()'

Descriptions of temperature controller functions:

All functions for the temperature controllers can only be used in the EXPERIMENT section of the EDL script.

`temp_contr_name()'

Returns a string with the name of the temperature controller being used.

`temp_contr_temperature()'

This function returns the temperature (in Kelvin). If the device has only a single sample channel the function accepts no arguments (like for the Bruker BVT3000). Otherwise it accepts an optional argument, the sampel channel to be used. This then becomes the default sample channel that is used when the function is called again, that time without an argument. If no sample channel has been set before (either by a call of this function or temp_contr_sample_channel()) the default sample channel is used. This is channel 1 for the Oxford Instruments ITC503 and the channel set before the program was started at the front panel for the Lake Shore 330.

The function returned is always in Kelvin.

`temp_contr_sample_channel()'

This function only exists for the Oxford Instruments ITC503 and the Lake Shore 330 and returns when called with no argument the currently selected sample channel. For the Lake Shore 330 it returns 1 for channel A and 2 for channel B while for the Oxford Instruments ITC503 1, 2 or 3 get returned, indicating which of sample channel is selected.

Otherwise it can be used to select a new default sample channel. In that case it expects a single argument. This must either be an integer (1 or 2 for the Lake Shore 330 and also 3 (if available) for the Oxford Instruments ITC503 or a string with a single letter ("A" or "B" (and "C" for the three channels of the Oxford Instruments ITC503).

Please note that the default sample channel can also be changed via a call of temp_contr_temperature().

Setting a sample channel takes about half a second with the Lake Shore 330. For the Oxford Instruments ITC503 not all sample channels may be usable, there are models with different numbers of channels and this number is a compile time option that has to be set in the configuration file for the device.

`temp_contr_heater_sensor()'

This function only exists for the Oxford Instruments ITC503 and the Lake Shore 330 and allows to set or query the sensor that is used for active control of the temperature when comparing to the setpoint (the target temperature). It may differ from the sensor used when calling temp_contr_temperature().

The function currently only is implemented for the Oxford Instruments ITC503. If called without an argument it returns 1 or 2 or 3 (as far as available). To set a different sensor call it with one of these numbers or with a single letter string "A", "B" or "C".

Please note: not all sensor channels may be usable, there are models with different numbers of channels and this number is a compile time option that has to be set in the configuration file for the device.

`temp_contr_setpoint()'

The function allows to query or set the setpoint, i.e. the target temperature the device will try to achieve and maintain when active control is one. If called without an argument it returns the setpoint temperature in Kelvin. To set a new setpoint value call it with the new target temperature in Kelvin.

This function is only available for the Oxford Instruments ITC503 and the Bruker BVT3000.

`temp_contr_state()'

This function can be used to change the state of the device, i.e. if active temperature control is on or off.

This function is currently only available for the Oxford Instruments ITC503. If called without an argument it returns an integer between 0 and 5, where 0 stands for manual control, 1 for automatic control of the heater power, 2 for automatic control of the gas flow, 3 for full automatic control (both heater power and flow rate). To set the state call it with a single argument, either with one of the above numbers or one of the strings "MANUAL", "HEATER_AUTO", "GAS_AUTO" or "AUTO" (both heater and gas flow are controlled by the device).

Please note: while implemented this function doesn't work for the Bruker BVT3000 when trying to switch to manual mode, the device seems to be always in automatic mode and doesn't accept the command (as described in the manual) to switch to manual.

`temp_contr_heater_state()'

This function only exists for the Bruker BVT3000. If called without an argument it returns if the heater is on or off. If called with a boolean argument (either on of the strings "ON" or "OFF" or an integer value, where everything except 0 is treated as true) the heater gets switched on or off.

Please note: the heater can be switched on only if the gas flow isn't missing. Also note that changing the heater state has no influence on the heater power setting as set or queried with temp_contr_heater_power().

`temp_contr_heater_power()'

This function is currently only available for the Oxford Instruments ITC503. If in manual mode or when only the gas flow is controlled this function allows to adjust the heater power by calling it with an argument between 0 and 99.9, representing the percentage of the heater power limit that can be set via temp_contr_heater_power_limit(). If the device isn't in manual or gas flow control mode a warning gets printed out and the heater power remains unchanged.

If called without an argument the function returns the current setting of the heater power.

Please note: this function is also implemented for the Bruker BVT3000 but can't be used since it would require that the device is in manual mode - but which this device doesn't seem to allow.

`temp_contr_heater_power_limit()'

This function is currently only available for the Oxford Instruments ITC503 and the Bruker BVT3000. It allows to set a limit in the heater power. The function expects a single argument, for the Oxford Instruments ITC503 a value between 0.0 and 99.9 (where 99.9 corresponds to the maximum possible output voltage of 40 V) and between 0.0 and 100.0 for the Bruker BVT3000.

For the Oxford Instruments ITC503 the function can only be called while the device is in manual mode, otherwise only a warning message is output (and the function returns -1.0 instead of the new value of the limit). For this device it is also not possible to query the heater power limit by calling the function without an argument,

`temp_contr_check_heater()'

This function is currently only available for the Bruker BVT3000. It allows to check if the heater isn't overheating. The function takes no arguments and returns 0 if the heater is ok and 1 if the heater is overheating.

`temp_contr_gas_flow()'

This function is currently only available for the Oxford Instruments ITC503 and the Bruker BVT3000. It allows to set or query the gas flow. The function expects a single argument, a value between 0.0 and 99.9, representing the percentage of the maximum gas flow. If the device isn't in manual or heater power control mode a warning gets printed out and the heater power remains unchanged.

To determine the current gas flow call the function without an argument.

For the Bruker BVT3000 setting the gas flow is only possible if the heater state is on as can be set or queried by temp_contr_heater_state().

`temp_contr_tune_state()'

This function is only available for the Bruker BVT3000. It allows to enable adaptive and/or self tune mode (or query the state by calling the function without an argument). The only accepted argument is a string or an integer with the following values: "OFF" (0) to switch off both adaptive and self tuning, "ADAPTIVE" (1) to select adaptive tuning only, "SELF" (2) for self tuning only and "SELF+ADAPTIVE" (3) to enable bot adaptive and selftuning.

`temp_contr_proportional_band()'

This function is only available for the Bruker BVT3000. It allows to set or query the proportional band setting of the PI controller. If called without an argument the current value for the proportional band (in K) is returned, otherwise a new value for the proporional band is set accordingly (accpted values range from 0.0 to 999.9).

The value for the proportional band can only be changed if neither adaptive or self tuning is running.

`temp_contr_integral_time()'

This function is only available for the Bruker BVT3000. It allows to set or query the integral time setting of the PID loop. If called without an argument the current value for the integral time (in s) is returned, otherwise a new value for the integral time is set accordingly (accpted values range from 0.0 to 9999.9).

The value for the integral time can only be changed if neither adaptive or self tuning is running. When setting this value to 0.0 before switching on adaptive of self tuning the PID loop will be tuned without this parameter (unless large offsets exist for very long times).

`temp_contr_derivative_time()'

This function is only available for the Bruker BVT3000. It allows to set or query the derivative time setting of the PID loop. If called without an argument the current value for the derivative time (in s) is returned, otherwise a new value for the integral time is set accordingly (accpted values range from 0.0 to 999.9).

`temp_contr_cutbacks()'

This function is only available for the Bruker BVT3000. It allows to set or query the low and high cutback value. If called without an argument an array with two floating point numbers is returned, where the first element is the low cutback value and the second is the high cutback value. To set new cutback values call the function with two arguments, first the new low cutback and then the new high cutback value.

The cutback values can't be changed while self tuning is running. Setting one or both of these values to 0.0 before switching on self tuning will result in the parameter not being used for tuning the PID loop.

`temp_contr_adaptive_tune_trigger()'

This function is only available for the Bruker BVT3000. It allows to set or query the adaptive tune trigger level (i.e. minimum deviation of the temperature from the setpoint at which adaptive tuning is done when adaptive tune is switched on). To determine the value call the function without an argument. To set new value call it with a temperatur (in K). Accepted vales range from 0.0 to 231.7.

`temp_contr_ln2_heater_state()'

This function only exists for the Bruker BVT3000 and only can be used when fitted with an LN2 evaporator. If called without an argument it returns if the LN2 heater is on or off. If called with a boolean argument (either on of the strings "ON" or "OFF" or an integer value, where everything except 0 is treated as true) the LN2 heater gets switched on or off.

Please note: Changing the LN2 heater state has no influence on the LN2 heater power setting as set or queried with temp_contr_ln2_heater_power().

`temp_contr_ln2_heater_power()'

This function is currently only available for the Bruker BVT3000 and can only be used if fitted with a LN2 evaporator. It allows to adjust the LN2 heater power by calling it with an argument between 0 and 100.0, representing the percentage of maximum LN2 heater power. If called without an argument the function returns the current setting of the LN2 heater power.

Please note: Changing the LN2 heater power has no immediate effect if the LN2 heater isn't swicthed on (as can be determined or chaneged using temp_contr_ln2_heater_state().

`temp_contr_check_ln2_heater()'

This function is currently only available for the Bruker BVT3000 and can only be used if fitted with a LN2 evaporator.. It allows to check if the LN2 tank needs a refill or is even empty. The function takes no arguments and returns 0 if there's still enough LN2, 1 if a refill is advisable and 2 if the LN2 is empty.

`temp_contr_lock_keyboard()'

Usually, during an experiment the keyboard of the temperature controller is locked. But for situations where it would be useful to be able to control the device also via its keyboard it can be unlocked (and also re-locked) from within the script. To unlock the keyboard call this function with an argument of 0 or "OFF", to re-lock the keyboard call it again with a non-zero argument, "ON" or no argument at all.

This document was generated by Jens Thoms Toerring on September 6, 2017 using texi2html 1.82.