MKS 937B - Page 37

MKS 937B Operation Manual
37
Select the gas type by moving the cursor to the Gas Type box and pressing
Enter
. Use the
or keys to select the correct gas type for the sensor. Three gas types (N
2
, Ar and He)
can be selected. The default setting is N
2
.
3. Factory Default
If YES is selected for Factory Default, the Manual Zero and ATM Cal data are restored to the
factory default values. The default setting for the Factory Default function is NO.
A small U under the gauge type indication on the front panel LCD display (PR or CP) will
disappear if the gauge was manually calibrated.
4. Auto Zero
Use the
or keys to select a valid gauge for autozeroing the Pirani (PR) or Convection
Pirani (CP). An ion gauge must be used as the zero reference.
The zero will be executed for Pirani only when:
(1) The system pressure is less then 1X10
-6
torr (1x10
-5
torr for Convection Pirani).
(2) The Pirani reading is within the range 5x10
-5
torr (5x10
-4
torr for Convection
Pirani) and 1x10
-2
torr.
The default setting for the Auto Zero function is NO.
Ensure that the Pirani/CP and the reference auto-zero ion gauge sensor are
connected to the same chamber at all times.
5. Manual Zero
The Pirani/CP sensor can be manually zeroed when YES is selected for this function. Ensure
that the system pressure is less than1x10
-6
torr (1x10
-5
torr for CP) before executing a Manual
Zero. The Manual Zero function will abort if the overall offset is over 1x10
-2
torr. The default
setting for the Manual Zero function is NO.
6. ATM Value
This value is used to calibrate the Pirani/CP at atmospheric pressure. The default value is
760 torr. Recall that elevation and weather will affect local atmospheric pressures.
7. ATM Cal
When YES is selected for the ATM Cal function, the ATM Value will be entered as the
reference pressure for the ATM calibration of Pirani/CP. The default setting for the ATM Cal
function is NO.
8. Relay
Relays for each PR/CP channel are preset (2 per channel) as shown below. These values
are auto-detected.
Sensor location A1 A2 B1 B2 C1 C2
Relay assigned 1 & 2 3 & 4 5 & 6 7 & 8 9 &10 11 & 12
9. Enable
There are three ways to enable a relay: