Hach Anatel PAT700 User Manual page 32

Installation
Wiring Termi
Description
connector nal
1 Common connection for external sourcing (+)
2 Digital input 1 voltage source return input (–)
3 Digital input 2 voltage source return input (–)
•
4 •
•
5 •
Page 30
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
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 56 for instructions on inverting the operation of Digital Input 1 or Digital
Input 2.
Table 8 Discrete input wiring terminal designations
12 VDC power supply +
Connect only if output device requires power
supply
12 VDC power supply –
Connect only if output device requires power
supply
Table 8. Both inputs are optically isolated. The
Variable
Common
Initiates TOC analysis
Analyzer mode
Output power supply
Output power supply
Designation
DI1/2+
DI1–
DI2–
+12V
GND