MKS 246C, Инструкция по эксплуатации

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External Set Point Control Chapter Four: Operation
64
3. Plug the controller’s AC LINE CORD into the power line and turn on the power switch.
Note
Allow the controller to warmup for at least 1½ hours before adjusting the
zero.
4. Pump the chamber down below the resolution of the transducer and adjust the zero for a
reading of ±0000 on the controller’s digital panel meter (DPM).
On controllers without a DPM, adjust the Set Point Control to zero and adjust for a zero
reading on the Error Meter.
5. Place the SET POINT SOURCE SWITCH on each 246 unit to the RATIO position.
6. Ensure that the SET POINT CONTROL is properly calculated and adjusted for each
MFC in use.
Refer to step 8, page 57, for an example calculation. Adjust the flow rate with the 246
unit’s SET POINT CONTROL to achieve the desired flow rate and ratio between the
units and the desired pressure (within a factor of 2) in the chamber.
7. Turn the flow ON by placing the FLOW CONTROL SWITCH on each 246 unit to the
ON position.
The set point signal is applied to the MFC and flow begins after a slight delay. The
correct flow is realized within approximately 1.5 seconds, depending on the type of MFC
being used.
8. Read the chamber pressure on the controller’s digital panel meter.
To read pressure on a controller without a meter, adjust the controller’s set point until the
error meter reads zero, then multiply the Set Point reading times the Full Scale of the
transducer (1000 counts = full scale). When the pressure is within the desired 2 to 1
range, the system is ready for automatic control.
If the pressure cannot be adjusted to within the factor of 2, then modification of the
system may be necessary.
•
Too high of a pressure requires increased pumping capacity or smaller MFCs for less
total flow
•
Too low of a pressure requires reduced pumping capacity or larger MFCs for greater
total flow