Brooks Instrument XacTorr CMX160 User Manual
Page 12
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2.5 RELAYS
Two electromechanical relays are provided in CMX configured with the 15-Pin
D-Sub connector option (see Ordering Code on page 11). The relays are UL
recognized components
rated for 100,000 cycles at 1A, 30V DC, Resistive.
Associated LED indicators located on top of the device illuminate when the coil
of the associated relay is energized. Each relay has a normally open (NO) and a
normally closed (NC) contact with a common connection (Single Pole Double
Throw). The contacts are accessed through the 15-Pin connector. (refer to
Figure 21, CMX RS-485 Port (2.5mm Jack), on Page 20)
The relays are digitally programmed (with use of the CMX User Software)
individually for the following properties:
(Refer to the CMX Software Manual for procedures to set the relays)
• Direction of Relay Actuation:
Above Setpoint (ascending pressure): Relay is energized above the setpoint.
Below Setpoint (descending pressure): Relay is energized below the setpoint.
• Setpoint Pressure:
Pressure value, in percent of full-scale (0-100%) at which the relay actuates.
• Hysteresis:
The amount by which the pressure must return past the setpoint value before
the relay will be de-actuated (adjustable from 0-20% of full-scale).
The following graphs provide an example of the relay behavior:
Figure 4: Direction of Relay Actuation: Above Setpoint
Figure 5: Direction of Relay Actuation: Below Setpoint
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