Televac® MX7B Cold Cathode Ionization Gauge

Part Numbers: 2-8940-NPT, 2-8940-075, 2-8940-100, 2-8940-125, 2-8940-KF25

Compatible With: MX Active Gauge EthernetIP Gateway

Features and Benefits:

  • Highly contamination resistant cold cathode ionization gauge design
  • Compact design
  • Color OLED display
  • Configurable 0 to 10 V analog output
  • Set point relay and open connector for process control
  • RS-485 and USB communications standard
  • EthernetIP communications available via the MX Active Gauge EIP Gateway
  • Easily cleaned Penning ionization gauge for extended sensor lifetime
  • ISO 17025 accredited and NIST traceable calibrations optional
  • Rapid turn-around for calibration and service

The Televac® MX7B is an active vacuum gauge (also called an analog vacuum gauge or a digital vacuum gauge) featuring the well-known Televac® 7B cold cathode ionization gauge. This gauge provides robust, contamination-resistant measurement from 10-3 to 10-8 Torr. The Penning ionization gauge is easy to disassemble, making gauge replacement and cleaning stress-free while also saving you time and money.

Our engineers designed this cold cathode ionization gauge with end users in mind, with a particular focus on heat treat and vacuum furnace end users who wanted full range vacuum measurement from a durable and cleanable digital vacuum gauge or analog vacuum gauge. The MX7B Penning ionization gauge is designed for use with our digital micron gauges, the MX4A convection active vacuum gauge or MX2A thermocouple active vacuum gauge, for a combined range of 10-8 Torr to 1000 Torr.

This system is also a drop-in replacement for the Televac® MP7ER cold cathode active vacuum gauge.

MX7B Cold Cathode Active Vacuum Gauge

Product Description
3/4” NPT Brass
3/4” NPT Brass
PN: 2-8940-NPT

3/4” Straight Stainless Steel
3/4” Straight Stainless Steel
PN: 2-8940-075

1" Straight Brass
PN: 2-8940-100

1 1/4
1 1/4" (1.25”) Straight Brass
PN: 2-8940-125

NW25/KF25 Stainless Steel
NW25/KF25 Stainless Steel
PN: 2-8940-KF25

D-Sub 15, 15 Conductor Cables (Flying Leads)

Product Description
10′ D-Sub 15, 15 Conductor Cable (Flying Leads)
10′ D-Sub 15, 15 Conductor Cable (Flying Leads)
PN: 2-9858-010
20′ D-Sub 15, 15 Conductor Cable (Flying Leads)
20′ D-Sub 15, 15 Conductor Cable (Flying Leads)
PN: 2-9858-020
35′ D-Sub 15, 15 Conductor Cable (Flying Leads)
35′ D-Sub 15, 15 Conductor Cable (Flying Leads)
PN: 2-9858-035
50′ D-Sub 15, 15 Conductor Cable (Flying Leads)
50′ D-Sub 15, 15 Conductor Cable (Flying Leads)
PN: 2-9858-050
65′ D-Sub 15, 15 Conductor Cable (Flying Leads)
65′ D-Sub 15, 15 Conductor Cable (Flying Leads)
PN: 2-9858-065
100′ D-Sub 15, 15 Conductor Cable (Flying Leads)
100′ D-Sub 15, 15 Conductor Cable (Flying Leads)
PN: 2-9858-100

D-Sub 15, 6 Conductor Cables (Flying Leads)

Product Description
20’ D-Sub 15, 6 Conductor Cable (Flying Leads)
20’ D-Sub 15, 6 Conductor Cable (Flying Leads)
PN: 2-9873-020
50’ D-Sub 15, 6 Conductor Cable (Flying Leads)
50’ D-Sub 15, 6 Conductor Cable (Flying Leads)
PN: 2-9873-050
100’ D-Sub 15, 6 Conductor Cable (Flying Leads)
100’ D-Sub 15, 6 Conductor Cable (Flying Leads)
PN: 2-9873-100

Wall Power Supply

Product Description
100-240 V AC/47-63 Hz, Plug Types A, C, G, I
100-240 V AC/47-63 Hz, Plug Types A, C, G, I
PN: 2-7900-097

Replacement Parts

Product Description
Anode Assembly
Anode Assembly
PN: 2-7900-707
Operating Range 1*10-8 Torr to 1*10-3 Torr
Display OLED
Digital Communications RS-485, USB (micro)
Analog Output Configurable 0 to 10 V DC
Programmable Set Points 2
Set Point 1 Open collector
Set Point 2 Relay
Supply Voltage 22 V DC to 26 V DC
Maximum Power 8 W
Calibration Medium Dry air or nitrogen
Overpressure 150 PSI
Digital Output Resolution 3 significant digits with exponent
Analog Output Resolution 16 bits
Operating Temperature 0 °C to 50 °C
Storage Temperature -20 °C to 60 °C
Bakeout Temperature 120 °C
Response Time ≤150 ms
Display Readable Distance 3 m (10 ft)
1*10-7 to 1*10-3 Torr ±30% of reading
Analog Output ±10 mV
Pin Description
1 Analog Out (Ground)
2 RS-485 A (-)
3 SP2 NC
4 SP2 NO
5 SP1 Open Drain
6 Do not connect
7 Do not connect
8 Supply Voltage (+)
9 Analog Out (0 to 10) V
10 RS-485 B (+)
11 SP2 Com
12 SP1 Source
13 Sensor Voltage Control (Ground)
14 Sensor Voltage Control (+)
15 Supply Voltage (Ground)
Electrical connections diagram (pin diagram) for the Televac® MX7B Cold Cathode Active Vacuum Gauge.

The MX7B has two set points. Set point 1 is an N-Channel 60 V MOSFET open collector. It has a maximum current rating of 1 A. The datasheet can be found at

Set point 2 is a relay with a maximum switching voltage of 220 V DC (250 V AC) and a maximum switching current of 2 A. The datasheet can be found at

Stainless Steel
Fluoropolymer Elastomer
Housing Aluminum
Weight with Sensor 1 kg (2 lbs)
Weight without Sensor 0.3 kg (0.6 lbs)
Dimensional drawing of the Televac® MX7B Cold Cathode Active Vacuum Gauge.
Certified to CAN/CSA C22.2 No. 61010-1-12
CE certified to EN 61010-1, EN 61236-1, EN 55011
RoHS compliant
EAC certified
ISO 17025 accredited calibration optional
NIST traceable calibration optional
Quantity Discount
1 List
5 2%
10 5%
15 7%
20 10%
25 13%
30+ 15%

D-Sub 15 Cable Quantity Discounts

Quantity Discount
1 List
50 5%
75 10%
100+ 15%

All-in-one sensor, controls, and display

Televac® active gauges (analog vacuum gauges and digital vacuum gauges) feature an easy to read OLED display with four capacitive touch controls, allowing users to interface directly with the unit. The MX7B has many customizable features which can be changed through the user interface (or via RS-485, USB, and EthernetIP), including units of measurement, gas type, set points, and output.

Gas Types

  • Nitrogen
  • Hydrogen
  • Helium
  • Argon
  • Krypton
  • Carbon Dioxide

Measurement Units

  • Torr
  • Millibar
  • Kilopascal

The MX7B has 2 set points, one relay and one open collector, and a selectable analog output option. The analog output is a configurable 0-10 V output that includes options for linear, linear-by-decade, and logarithmic formats.

Durable and contamination resistant

Engineered for harsh environments, the MX7B’s Penning ionization gauge is more resistant to contamination than inverted magnetron vacuum gauges. Heat treaters around the world trust Televac® cold cathode gauges because they are unaffected by the inrush of air, have no filaments to burn out, and are relatively unaffected by vibration. Less maintenance means minimal downtime and lower service costs for end users.

Simplified digital calibrations

Televac® active vacuum gauges, are an ideal solution for vacuum furnace applications where calibration frequency requirements vary between rough vacuum gauges and high vacuum gauges, outlined in the AMS2769 standard. Under this standard, convection gauges need to be calibrated annually but cold cathode gauges must be calibrated every three months. A major benefit of using active gauges is that you don’t have to send back your whole system. Instead of sending back a controller, cables, and every sensor on your system, you can send back just the gauge that needs calibration.

Easy disassembly

The sensor at the heart of this active gauge, the reliable 7B Penning cold cathode gauge, has been trusted by heat treaters and many other users for decades because it’s durable and easy to disassemble for cleaning. The MX7B continues this legacy with a streamlined design that makes taking the unit apart as simple as possible. Click here to watch the 7B disassembly demo.

Looking for EthernetIP communications?

Our digital vacuum gauges can also be connected to an EthernetIP network via the new Televac® MX Active Gauge EthernetIP Gateway, the first and only solution designed to provide EthernetIP communication between Televac® active vacuum gauges and Rockwell Automation® Allen-Bradley® PLCs.

A convenient reference gauge

Looking for a more convenient reference gauge for your system? The MX7B digital vacuum gauge can be used as a reference gauge for calibration in the field thanks to its compact size and design so it’s easier to send back for calibration than a controller system.

Digital vacuum gauges versus controllers

The size and configuration of your vacuum system is perhaps the biggest factor when deciding between whether to use a controller and passive gauges (such as the MX200) or multiple digital vacuum gauges.  In general, digital vacuum gauges, or active gauges, are considered more efficient, easier to maintain, and offer more flexibility in instances where cabinet space is limited. However, there are a few circumstances where a controller solution would be the better option. For applications where radiation is a factor (i.e. national labs), controllers are kept at a distance from the radiation and are connected by cables as radiation will destroy the PCBs/microcontrollers. Another benefit that a controller offers is the remote display, which some users find helpful.