TELEVAC MX7M, Instruction Manual

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Instruction Manual MX7M Active Gauge
Figure 2: MX7M Electrical Connection Information
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)
2.3 Turning the High Voltage On and Off
The MX7M has an operating range that does not include measurement above 1
×
10
− 2
Torr. If the unit
is operated above 1
×
10
− 2
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.
The MX7M 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 MX7M connector.
To turn on the sensor when Menu Control is selected, use one of the following two options: from the
Measurement Screen, press SEL to navigate to the Vsense Control, then press ENT to unlock the con-
trol, press UP to toggle the status to ON, and then press ENT to save the change. The high voltage
should now turn on. In Menu Control mode, the high voltage can also be toggled by sending the
appropriate command to turn on the sensor through RS-485 or USB Communications. To turn off the
sensor in Menu Control mode, navigate to the Vsense Control screen, press ENT to unlock the menu,
press UP to toggle the status to OFF, and press ENT to save the change. Alternatively, when in Menu
Control mode, the user may send the appropriate command to turn off the sensor through RS-485 or
USB Communications. See section 3 for more information.
To turn on the sensor when Hardware Control is selected, short pins 13 and 14 together. To turn off
the sensor, open the path between pins 13 and 14. This functionality is included to easily interface
with a low vacuum gauge, such as the Televac MX2A or MX4A, to automatically control the unit via an
open collector or relay. Contact Televac Sales for more information or see Application Note 3022.
email: sales@frederickscompany.com tel: +1 215 947 2500 web: frederickscompany.com mx7m_im rev C 6 of 23