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July 2022
Subject to
change without notice
Pag
e
39
Connection of external components
Example calculation:
An reagent P25-5 is used for the analysis. Measuring range 0.2 mmol/l to 5 mmol/l.
Upper measured value is set to 5 mmol/l, which corresponds to 20 mA.
For the current interface type "0 - 20 mA", 0 mA corresponds to 0 mmol/l.
For the current interface type "4 - 20 mA", 4 mA corresponds to 0 mmol/l.
Calculation for current interfaces type "0 - 20 mA
𝐼 = 0 𝑚𝐴 +
(20 𝑚𝐴 − 0 𝑚𝐴) ⋅ 1,2 𝑚𝑚𝑜𝑙/𝑙
5 𝑚𝑚𝑜𝑙/𝑙
[𝑚𝐴]
𝐼 = 4,8 𝑚𝐴
4.8 mA corresponds to 1.2 mmol/l.
Calculation for current interfaces type "4 - 20 mA
𝐼 = 4 𝑚𝐴 +
(20 𝑚𝐴 − 4 𝑚𝐴) ⋅ 1,2 𝑚𝑚𝑜𝑙/𝑙
5 𝑚𝑚𝑜𝑙/𝑙
[𝑚𝐴]
𝐼 = 7,84 𝑚𝐴
7.84 mA corresponds to 1.2 mmol/l.
Operating status via analogue current interface
The operating status of the unit can be transmitted via the current interface terminals 11 and 12.
Programming: Menu > Settings > Outputs > Current interface type
Choices:
•
0 - 20 mA status
•
4 - 20 mA Status
Operating status
Power interface
0 - 20 mA status
4 - 20 mA Status
Operation
3.5 mA
6.8 mA
Limit value undershot
7.5 mA
10.0 mA
Limit value exceeded
12.5 mA
13.6 mA
Reagent level < 10 %
16.5 mA
16.8 mA
Malfunction
0 mA
4 mA
The specifications listed here may have a deviation of ± 0.3 mA.