Chapter One: General Information
Introduction
17
Chapter One: General Information
Introduction
The MKS Type 670B High Accuracy Signal Conditioner is designed to work with the MKS 300
and 600 Series Baratron
®
high accuracy pressure transducers. The 670 instrument consists of the
power supplies, heater control, and oscillator necessary to interface with the compatible MKS
pressure transducers. When combined with the Type 274 multiplexer, the 670 instrument can
measure the pressure from up to three pressure transducers (from either the 300 or 600 Series, or
a combination of both). The front panel includes three channel selector keys, each with a light in
the upper left hand corner that illuminates when the channel is selected to visually indicate the
active channel. The display screen can list the pressure reading as a 3½, 4½ or 5½ digit number.
The unit is designed to fit in the standard ½ rack mount.
You can control the 670 instrument remotely, using either RS-232C or IEEE-488 (IEEE-488.2)
communications. Both methods of remote communication allow you to perform virtually all the
functions available through the front panel. While operating in the
REMOTE
mode, the
instrument expects to receive commands through the RS-232 port, the IEEE-488 bus, or the rear
panel connectors, so it locks out any commands entered through the front panel. This eliminates
the possibility of accidental command entries. In
LOCAL
mode the instrument accepts
commands issued by using the front panel only. During
LOCAL
mode operation, the RS-232
port and the IEEE-488 bus can be used to report status information. Remote communication
commands to change operating parameters will not be accepted while in
LOCAL
mode.
The 670 instrument contains two alarm trip points. The high and low values for each trip point
define a “normal” operating range for the pressure signal. If the pressure signal deviates from the
range defined by the trip points, a trip point becomes activated and causes a relay to change state.
The adjustable hysteresis feature prevents any “relay chatter” because it defines a deadband
around each trip point. This deadband provides a “margin of error” since the relay does not
change state until the pressure signal exceeds, or drops below, the trip point setting plus the
hysteresis value. Therefore, an alarm condition does not occur if the pressure signal hovers
around the trip point. In addition, you define the normal state for each relay as either energized
or de-energized.
The averaging feature of the 670 instrument reduces fluctuation in the pressure reading by
averaging multiple readings. This is especially useful in systems where the pressure is unstable.
Instead of displaying every data point, the 670 instrument can average incoming data points with
a specified number of data points collected previously. The display shows the averaged value,
rather than the actual new data point. This averaging acts to smooth out the pressure readings.
The number of points to average can range from 1 and 99, inclusive.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
