e-Vision and e- LP101013.100 – 01 January 2004
MKS Instruments, Spectra Products
15
The maximum common mode voltage is 60V DC or Peak AC, current limited to
2mA.
3.3 Power indicator
The power indicator is a 3mm Green LED labeled
“POWER”
on the rear panel of
the unit. This is illuminated when power is applied to the unit.
3.4 Ethernet connector
This is an RJ45 style connector labeled
“ETHERNET”
on the rear panel of the unit.
It is used to connect the e-Vision
to the host computer, this accepts standard Cat5
patch cables, as follows:
If connecting directly to a PC, use a crossover or cross-wired Cat5 Patch cable.
If connecting to a network, use a standard Cat5 Patch cable.
3.5 External trip
The external trip connector is a 3.5mm Jack socket mounted to the right of the
Power connector on the rear panel and labeled
“X-TRIP”.
The external trip feature is used to protect the filaments and electron multiplier
from exposure to high pressures. It allows an independent total pressure gauge or
signal from a vacuum control system to be connected to the e-Vision.
It is the most effective of the trips available and we would always recommend its
use.
The external trip input can be driven in three ways.
1. Uncommitted relay contact
This is a low voltage (+5V, 1mA) contact. The contact should be closed for normal
operation, open to trip the filaments or if the protective equipment is switched off.
2. Open collector TTL drive
The output transistor should be on for normal operation, off for trip or if the
protective equipment is turned off.
3. Totem pole TTL drive
The signal should be low for normal operation, high for a trip condition or if the
protective equipment is switched off.
The external trip circuitry is galvanically isolated from the system ground. The
maximum common mode voltage is 60V DC or peak AC, current limited to 2mA.
