MKS Baratron 631D, Instruction Manual, Page: 52 / 64

Chapter Five: Optional Solid-State Relay System
44
Figure 8: Location of the Trip Point Adjustment Pots and Trip Point Signal Output
Note
The trip point adjustment voltage ranges from 0 to 10 Volts,
corresponding to the pressure range of the unit zero to full scale.
Trip Point Direction
The trip point direction defines the direction of pressure change that will turn ON the solid–state
relay’s trip points. The direction of each relay is preset during manufacturing of the relay (A)
when the pressure rises above the trip point value, or (B) when the pressure drops below the trip
point value. Each relay functions independently, so each of the two relays can be set to trip in the
same or in opposite directions. The customer can choose the direction of each trip point relay
using the appropriate model code, see Appendix B: Model Code Explanation, page 51.
If the preset direction for Trip Point A is “above”; the trip point is turned ON as the pressure rises
above the specified trip point value. The trip point is not turned OFF until the pressure falls
below the value defined by the hysteresis, as shown in Figure 9, page 45. Figure 9 also depicts the
relay being turned ON when the initial pressure condition applied to the unit is above the trip
point value. The trip point hysteresis is preset as 0.3% of FS (0.030 Volts) and its purpose to
prevent undesired bouncing in the solid state relay.
Trip Point
Adjustment
POTs
Trip Point
Signal Ground
Access to
Trip Point
Voltage
Signals