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3.3 Open Collector Output
The Open Collector output can be used as a switch that responds
when the process value moves above or below a setpoint, or it
can be used to generate a pulsing signal with a rate proportional
to the process value.
•
Low:
Output triggers when process variable is less than the setpoint.
The output will relax when the process moves above the setpoint
plus the hysteresis value.
•
High:
Output triggers when process variable is greater than the
setpoint. The output will relax when the process variable moves
below the setpoint plus the hysteresis value.
Process
Hysteresis
Low Setpoint
Process
High Setpoint
Hysteresis
VIEW menu
•
During normal operation, ProcessPro displays the VIEW menu.
•
When using the CALIBRATE or OPTIONS menus, ProcessPro will return to the VIEW menu if no activity
occurs for 10 minutes.
•
To select the item you want displayed, press the UP or DOWN arrow keys. The items will scroll in a
continuous loop. Changing the display selection does not interrupt system operations.
•
No key code is necessary to change display selection.
•
Output settings cannot be edited from the VIEW menu.
View Menu for pH
All of the displays below are temporary. The permanent display will return after ten minutes.
Loop Output:
page 4 of 12
Time
Output active
Output inactive
Time
Display
7.00
pH
Monitor the Temperature input from the sensor.
12.6
º C
This is the permanent view display.
Input:
Monitor the millivolt input from the electrode. Use this display to determine the
307 mV
relative condition of your electrode during periodic calibration. (7 pH buffer = 0
mV, ±50 mV)
Monitor the 4-20 mA Loop output.
14.16 mA
Monitor date for scheduled maintenance or date of last calibration.
Last CAL:
06-30-01
>
EASY
Easy Cal is the fastest and simplest periodic calibration method. Requires 4 pH,
7 pH and 10 pH. (Any two)
CAL:
>
•
Proportional Pulsing
The Open Collector output will generate a 100 mS pulse at the
rate defined by settings in the CALIBRATE menu (see page 6)
In the example below:
•
The output will be 0 pulses/min. at pH values less than 5.0.
•
The output will be 50 pulses/min. at 7.5 pH.
•
The output will be 100 pulses/min. at pH values above 10 pH.
0 pulses
5
Starting point
Description
100 pulses
10
endpoint
pH/ORP
10.20 pH
25.0°C
‡ SIGNET 8750-1 pH/ORP Transmitter
ENTER
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