Granville-Phillips Mini-Convectron 275 Series, Installation, Operation And Service Instructions, Page: 13 / 52

Mini-Convectron
®
Module with DeviceNet
®
Digital Interface 5
Chapter 3 Introduction
3.1 General Description The Model 275 Mini-Convectron Vacuum Gauge Module, shown in
Figure 3-1, is a modular instrument that is capable of measuring vacuum
pressures from less than 1 x 10
-3
Torr to 1000 Torr N
2
equivalent (or air). The
275 Mini-Convectron Vacuum Gauge Module does not have external
controls or adjustments and is available in RS-485 and DeviceNet digital
interface and analog versions.
The DeviceNet digital interface version provides communication over
networks. The DeviceNet digital interface can be used to read pressure,
calibrate the gauge and configure the trip point relays.
The trip point relays can be used to control various devices such as; safety
interlock, valve, digital input for a scanner, or programmable logic
controller. The relay trip points can be set to customized pressure settings to
turn power ON or OFF to the appropriate device.
The Model 275 Mini-Convectron Vacuum Gauge Module is a rugged device
that is capable of many years of trouble-free service. However, there are
conditions that may cause the gauge tube to fail and should be avoided:
• Chemical Etching - exposure to fluorine, chlorine or mercury causes the
sensor wire to become chemically etched and damaged.
• Too Much Power - if the gauge electronics and gauge tube are connected
while the gauge electronics are powered ON and the gauge tube is at
vacuum, a spike in the bridge voltage can occur at initial contact and
damage the sensor wire. Always turn power OFF or unplug the gauge tube
before connecting the gauge to the module electronics.
• Shock - extreme shock, such as dropping a gauge, can cause a weld to fail.