M&C EC-30C - How to Calculate Ma-Value Based on Measured Temperature

EC-30C | 1.00.02 +49 2102 935 888 www.mc-techgroup.com 69
12.2.2 How to calculate mA-value based on measured temperature
Based on the displayed deep-cooling temperature, the value of the mA-output can be
determent. For this calculation you can use the following formulas:
For T
min
≤ 0 °C (32 °F):
I
mess
=
(
(
T
      
+∆T
m 
∗ ∆I
∆T
)
+ I
offset
)
display
For T
min
> 0 °C (32 °F):
I
mess
=
(
(
T
      
-∆T
m 
∗ ∆I
∆T
)
+ I
offset
display
With the following values for I
offset
and ∆I:

=
0
0
0
m , wenn
, wenn
, wenn
, wenn
− 20
m
 − 20
m

m

m

m
m

m

∆I
=
20 − 20
16
4
4
4
− 20
offset
when
when
when
when

Increments and resolution of the mA-output
The mA-output with the 0-20 mA setting has 400 increments per range. For the range of
4-20 mA the increments are proportionally reduced to 320.
Depending on the temperature range (see how to set the temperature range on page
34 chapter ‘7.9 Parameter menu’ ), the resolution or accuracy of the mA-output can be
calculated as follows:
(T
max
- T
min
) / 400 for 0-20 mA
or:
(T
max
- T
min
) / 320 for 4-20 mA
Example:
Set: 4-20 mA for -30 °C to +30 °C (~-22 °F to 86 °F)
The resolution of the mA-output is:
[30 °C - (-30 °C)] / 320 = 0.1875 °C (0.34 °F)