Teledyne LXT-220 - Manual (Page 13)

Dissolved Oxygen Controller Introduction
Teledyne Analytical Instruments 13
Introduction
1.1 Overview
Teledyne’s Model LXT-220 Dissolved Oxygen Controller is a
robust and versatile instrument for the measurement and process control
of dissolved oxygen in a liquid component. Highly customizable, the
Model LXT-220 comes standard with a single 4-20mA current output
but can have as many as five. The current output is field selectable and
may be expanded to any range within the transmitter’s full operating
range. It can also be programmed as reverse acting; for example, a 4-20
mA output for a range of 0 to 10 ppm can be reversed to 10 to 0 ppm.
The standard instrument accepts a single input typically from a
Teledyne SP1 or SP2 Dissolved Oxygen probe however a dual input
option is available. This optional dual input extends the functionality of
the instrument to accept conditioned input from a variety of sensors for
specific process measurements such as:
• Second Dissolved Oxygen (DO) channel
• Resistivity/conductivity
• pH
• Oxidation-Reduction Potential (ORP)
• Specific Ion
For process control, the microprocessor based LXT-220
Transmitter employs a multi-bus system architecture for PID
temperature control and sensor-specific process variable outputs such as
DO, pH, ORP, Resistivity/Conductivity, and ion-specific element (ISE)
output as a function of multiple inputs. Up to six field-configurable
alarm or control relay outputs are available to the user to match
individual process needs. These relays can be field configured as high or
low alarms. Hysterisis (dead band) is defined by setting the ON and OFF
relay values. These relays can be configured to any of the input
parameters. (See Section 3.3.5).