User manual

PAT700 Total Organic Carbon Analyzer – Installation Page 27
Anatel Operator Manual
Discrete inputs
The analyzer has two discrete inputs, referred to as Digital Input 1 and Digital Input 2. Wiring
connects to terminals as listed in Table 2-8, page 27. Both inputs are optically isolated. The
inputs are rated for 5 - 30VDC, 2 - 15mA. Terminals 4 and 5 of the discrete input terminal
provides a 12 VDC output that can be used to drive each digital input. Both Digital input 1 and
input 2 share a common positive power connection.
The default state for each input is a high state (no voltage applied across the input). High state
is defined as no power applied across the input terminals. Low state
is defined as power
applied across the input terminals.
• Digital input 1 initiates a TOC analysis. When power is applied across pins 1 and 2
the analyzer input is changed from a high to low state. (When power is applied the
optical input LED is powered and the input is activated.) An input trigger of at least 500
mSec (0.5 seconds) is required. When a high to low trigger is detected on the input the
analyzer stops the current operation and runs a single TOC analysis. When the
analysis is complete, the analyzer returns to the mode defined by digital input 2. During
the TOC analysis, the analyzer ignores all subsequent triggers.
• Digital input 2 controls the analyzer run mode. If digital input 2 is not powered (High
state) the analyzer is in TOC mode. If power is applied across pins 1 and 3 the
analyzer input is changed from high to low and the analyzer will run in flow with
conductivity mode.
• The control required to activate digital inputs 1 and 2 can be configured by the user.
For example, Digital Input 1 can be configured to trigger from the default change from
high to low state or inverted to trigger from a change from low to high state. Refer to
TOC, page 54 for instructions on inverting the operation of Digital Input 1 or Digital
Input 2.
The following two wiring diagrams Figure 2-14 and Figure 2-15 illustrate the digital input
wiring:
Table 2-8 Discrete input wiring terminal designations
Wiring connector Terminal Description Variable Designation
1 Common connection for external sourcing (+) Common DI1/2+
2 Digital input 1 voltage source return input (–) Initiates TOC analysis DI1–
3 Digital input 2 voltage source return input (–) Analyzer mode DI2–
4 • 12 VDC power supply +
• Connect only if output device requires power
supply
Output power supply +12V
5 • 12 VDC power supply –
• Connect only if output device requires power
supply
Output power supply GND