Servomex SERVOTOUGH Oxy, Operator'S Manual

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© Servomex Group Limited. 2020 01910001B_8
# Only available if the 4
-
20mA output range is selected; this sets the lowest out
-
put current
during normal opera�on, and allows nega�ve gas concentra�ons to be monitored through the mA
output. For example, with an under
-
range se�ng of 3.8 mA, the mA output can be less than 4 mA
(which indicates a zero gas concentra�on), down to a minimum of 3.8 mA, where an output between 3.8
mA and 4 mA indicates a nega�ve gas concentra�on.
5.16.3 S
etting up the mA output parameters
Note:
If Auto ranging is selected, the way in which the output changes between the ranges
depends on the values you have set for the range change point and the hysteresis.
For example, if you set the range change point to 18% and set hysteresis to 1%, then:
The output value must be greater than 18% before changing from Range 1 to Range 2.
The
output value must be less than 18%
-
1% (17%) before changing from Range 2 to
Range 1.
Use the
following procedure to select Auto Ranging or manually select the range:
1.
Select: Se�ngs
mA output
2.
Select the Range op�on.
Figure
41 -
The mA configura�on screen
3.
Select the Range op�on you want the output to use (Range 1, Range 2 or Auto). If you
have selected Auto ranging, you must also set the range change and hysteresis values.
Figure
42 -
The mA range screen
4. Return to the mA configura�on screen (Figure 41) and select ’Set up’ op�on.
5.
Edit the Range high level and low level.