Simex SRP-N1186, User Manual

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User manual - METER SRP-N1186
Calculation of maximal allowable resistance of separator's input
Maximal resistance of the input (R
G max.
) and wires (R
W max.
) are calculated for circuit from
Figure
4.23
. Used symbols are described below.
U
S min.
- minimal sensor supply voltage (given in technical data of sensor),
U
g
- voltage drop on galvanic separator input (constant for 4-20 mA range of
current),
I
max.
= 20 mA - maximal current of current loop,
U
O
= 24V - sensor supply output voltage of device A,
R
O
= 3 0
Ω
- sensor supply output resistance of device
A
,
R
INP.
= 50
Ω
- measurement input resistance of device
A ,
R
G max.

R
W max.
=
U
O
−
U
S min.
−
U
g
I
max
−
R
INP.
−
R
O
Let U
S min.
=12V and U
g
=5V then:
R
G max.

R
W max.
=
24
−
12
−
3,5
0,02
−
50
−
30
=
270

If current loop is closed without the separator G , then sum of measurement input resistance
(R
B max.
) of device B ( Figure 4.23 ) and connections resistance (R
W max.
) should be not grater
than result of given below formula:
R
B max.

R
W max.
=
U
O
−
U
S min.
I
max
−
R
INP.
−
R
O
For example if U
S min.
=12V then:
R
B max.

R
W max.
=
24
−
12
0,02
−
50
−
30
=
520

4.4. MAINTENANCE
The unit does not have any internal replaceable or adjustable components available to
the user. Pay attention to the ambient temperature in the room where the unit is operating.
Excessively high temperatures cause faster ageing of the internal components and shorten the
fault-free time of the unit's operation.
In cases where the unit gets dirty do not clean with solvents. For cleaning use warm water with
small amount of detergent or in the case of more significant contamination ethyl or isopropyl
alcohol.
Using any other agents can cause permanent damage to the housing.
Product marked with this symbol should not be placed in municipal waste. Please
check local regulations for disposal of electronic products.
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