ATI Technologies d12 series - 4-20 Ma Control; Loop Adjustment; Figure 58. 4-20 Ma Control Page; Figure 59. Loop Adjustment Pages

ATI Series D12 Toxic Gas Transmitter with H10 Smart Sensor
Revision N (7/15) 60
4-20mA Control
The 4-20mA Control page permits adjustment of the analog output, and provides a method for
manually forcing it to a fixed value to overcome leakages, verify linearity, or test receiver alarms.
Figure 58. 4-20mA control page
Table 13. 4-20mA control variables
Variables
Description
Adjust_4mA
The Adjust_4mA variable is used to adjust the 4mA level on the 4-20mA output.
Adjust_20mA
The Adjust_20mA variable is used to adjust the 20mA level on the 4-20mA output.
Force
The Force variable is used to force the 4-20mA output to a fixed value. While the
variable is not selected, the displayed value is updated to show the real-time output
level. The loop is fixed at the instant the variable is selected, and the value may be
scrolled up and down as desired, between 3.5 and 22.0 mA.
Loop Adjustment
Loop adjustment consists of adjusting the 4 and 20 mA levels (order does not matter) by scrolling the
corresponding DAC
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value. This may be accomplished by reading a current meter connected across
the mA(+) and mA(-) terminals of TB1 on the transmitter’s Power Supply Board, or reading the display
of a calibrated, current loop receiver.
Select Adjust_4mA or Adjust_20mA and observe the following displays. Select DAC_Value and
scroll the displayed value up and down to achieve the desired output level, and touch Enter to save, or
Esc to exit without saving.
Figure 59. Loop adjustment pages
(DAC values shown may not match)
10
Digital-to-Analog-Converter value ranging 0 to 1023 (10-bits). Adjustment is performed at factory, values will vary from
transmitter to transmitter. This range may increase on future versions.
►Adjust_4mA
Adjust_20mA
Force= 4.0mA
>Menu >Setup >4-20mA >More
Warning:
Disable current loop receiver alarms before proceeding.
4-20mA_Output
Monitor the 4-20
►DAC_Value=23
>Adjust_4mA
>Menu >Setup >4-20mA >More
>Menu >Setup >4-20mA >More
4-20mA_Output
Monitor the 4-20
►DAC_Value=759
>Adjust_20mA
< Monitor the 4-20 while slowly
adjusting the DAC value.