AMMONIA User Manual
AMMONIA_User 9/09
4
3
4.0 4-20mA Outputs
4.1 4-20mA Output Setpoints
4-20mA Outputs display both the loop
current and its corresponding the 0-100%.
This example display occurs on installing a
new 4-20mA output card.
To view or modify a current output
Manual
setpoint
key
UP
or
DOWN
to the target output
and press
ENTER
.
Key
ENTER
@
Setpoints
.
Manual
= User sets current.
Auto
= Sensor controls current.
Displays the present
0%
to
100%
output setpoint.
Key
ENTER
to modify.
Key
UP
or
DOWN
to change the underlined digit.
Key
RIGHT
to move the underline.
Press
ENTER
to save the new
Manual Mode
setpoint
or
EXIT
to leave unchanged.
Key
EXIT
twice to view the effect of the new setpoint.
In the example we’ve increased the
loop current from
4.00mA
to
8.32mA
.
Editing, or Exit
27
Manual mode
27%
then
Setpoints
Configure
Manual Mode
0%
4-20mAOutput_D
4.00mA 0.0%
D
4-20mAOutput_D
8.32mA 27.0%
D
Manual Setpoint
Sidebar:
Manual Mode:
Use
Manual mode
to verify the 100% ON=20mA, OFF=4mA or modulate operation
of the proportional pump or valve that the 4-20mA output is controlling.
Use
Manual mode
to verify the monitoring input that is using the current loop value
to represent an Analyzer NH3, pH, or temperature sensor or ppm calculation.
Load Powered 4-20mA Loop:
4-20mA current outputs are powered by the loop load or by the Analyzer 15VDC power supply.
Building automation system typically supply 24VDC to power current loops. Current loop
controlled pumps and valves usually use the Analyzer 15VDC supply to power the loop.
Open Loop Alarm:
The DC isolated 4-20mA output alarms on an open loop or a loss of loop power.