Chapter 4
SQM-242 Multi
4-2
Show Sensors / Show Outputs:
Toggles the card reading area between displaying
individual sensor readings, and the average of all sensors assigned to an output.
Read/Stop:
Starts and stops the SQM-242 card(s) from measuring and controlling
deposition. When the card is stopped, all outputs are set to zero.
Mode:
Alternates between reading sensors and simulating sensor readings. Simulate
mode is useful for training purposes, since no sensors (or even an SQM-242 card!)
need to be installed.
In Simulate mode, sensors will not indicate a rate reading until the output power
reaches at least 50%. Also, we introduce some noise into the readings in Simulate to
better mimic an actual deposition process.
Init:
Enter card initialization values, then press the “Init” button to send the values to the
SQM-242 card(s). This must be done before sending any other settings. The values
will be saved on exit from the program.
Zero:
Sets the thickness reading of the selected sensor to zero. You can select a
specific sensor to zero all sensors on a card, or all sensors on all cards using the
Card/Sensor dropdown boxes. First select the sensor to be zeroed, then click “Zero.”
Map Sensors:
Assigns each sensor to an output. If a sensor is assigned to Monitor,
then it displays rate and thickness, but does not contribute to the control of any output to
rate setpoint. If a single sensor is assigned to an output, and the output mode is set to
PID, then that sensor serves as the “measured rate” input to the PID loop. If multiple
sensors are assigned to an output, then the average of all assigned sensors is used as
the “measured rate” input to the PID loop. If multiple sensors are assigned to an output
and a sensor fails, it is automatically excluded from the average.
Material:
Sends the Density, Zfactor, and Tooling parameters to the selected sensor(s).
Manual/PID:
Sets the output mode for the selected output(s). In PID mode, output
power is controlled by the output’s Loop settings, to achieve the desired Rate setpoint.
In Manual Power mode, output power is fixed at the Power setting. To change the
output power in ManPwr mode, enter a new Power value then click “Set Power.”
Alternates Sends the Density, Zfactor, and Tooling parameters to the selected
sensor(s).
Loop:
Sends the PID and rate setpoint parameters to the SQM-242 card(s).
FullScale:
Sends the Full Scale Volts, Maximum Power, and Slew Rate parameters to
the SQM-242 card(s).