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mx7b_im rev E Page
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4.
Set Up
4.1
Installation
4.1.1
Each MX7B is designed to be used in conjunction with a 7B sensor. The 7B sensor can be
mounted in any position however it is recommended to mount it away from any contaminants
that might be in the system as over time this can affect the measurement accuracy. Mounting
the 7B sensor close to the area where vacuum measurement is desired is preferred to increase
the accuracy. Each 7B sensor has a key that only allows for the MX7B to mate with the sensor in
the proper orientation. Rotate the MX7B until the correct alignment is obtained and the MX7B is
able to slide onto the 7B sensor. Connect the power connector to the top of the unit and be sure
to tighten the screws so that a firm connection is maintained.
4.1.2
Try to avoid connecting the MX7B to the vacuum chamber by long or narrow piping as this may
affect the accuracy and response time of the unit. Avoid mounting the unit near a heater within
the chamber as this may affect the measurement accuracy. Excessive vibration of the unit may
affect accuracy and decrease the life of the unit. Exposure to oils and other contaminants will
decrease the accuracy and decrease the life of the sensor. Do not expose the unit to corrosive
gases.
4.2
Electrical Information
4.2.1
Power connectors and adapters for use with the MX7B are available for purchase from Televac®.
Operators wishing to create their own adapters should refer to the pin out of the MX7B below.
Each connection labeled “Floating” has no connection and should remain so.
Pin Description
1
Analog Output (Ground)
2
RS-485 A(-)
3
SP2 NC
4
SP2 NO
5
SP1 Open Drain
6
Starter Output (5V)
7
Starter Output (Ground)
8
Supply Voltage
9
Analog Output (0-10 V)
10
RS-485 B(+)
11
SP2 Com
12
SP1 Source
13
Sensor Voltage Control
14
Sensor Voltage Control
15
Supply Voltage (Ground)
4.3
Turning the High Voltage On and Off
4.3.1
The MX7B has an operating range that does not include measurement above 1*10
−
3
Torr. If the
unit is operated above 1*10
−
3
Torr, the sensor will be damaged and electrical arcing inside the
sensor may occur. To prevent this, the unit should be paired with a low vacuum gauge, such as
the MX4A or MX2A, to ensure safe operation.
4.3.2
The MX7B provides two control methods for toggling the high voltage; Menu Control and Pin
Control. To select which method is used, navigate to the Vsense Control menu screen and select
either Menu or Pins. Pin Control is provided through pins 13 and 14 of the MX7B connector.
