Chapter 3 Calculating Offset And Gain Resistor Values; Calculating The Offset Resistor Values; Calculating The Gain Resistor Values - Mantracourt ICA1H User Manual

Chapter 3 Calculating Offset and Gain Resistor Values

Calculating the offset resistor values

The ICA1H and 2H can be used in a pseudo 'bipolar ±' mode by fitting a resistor 'R
shift the output voltage to a known level (V
of the load cell to be measured.
Use the following formula for the ICA1H and 2H to calculate the value of R
�� =
��������
(��
The gain will also need to be changed to account for smaller changes in output resulting from a given input change.
This means that the total mV/V will change:
For the ICA1H:
���������������� mV/V =
For the ICA2H:
���������������� mV/V =

Calculating the gain resistor values

The ICA range of strain gauge amplifiers are supplied un-calibrated but optimised for a sensitivity of 2.5 mV/V. To
accommodate other sensitivities the gain resistor 'R
according to the following formulae.
N.B. a high quality component e.g. 1 % 10-15 ppm/°C metal film resistor should be used for optimum performance. It
may be necessary to use a value from the less common E96 series to optimise the trim range.
�������� = (
���������������� ����/��
Where:
Model
ICA1H
ICA2H
ICA3H
ICA4H
ICA6H
The ICA4H has two surface mount gain resistors. These do not need to be removed if the gain is to be increased (a
lower mV/V input level). However, they need to be taken into account and an extra calculation stage is required:
�� = (
(1/��
11
Mantracourt Electronics Limited – ICA User Manual
) when the input is zero (0 mV/V) allowing both tension and compression
offs
148
− 0.1)
��������
10V
�������������� ������������ ��ℎ��������
5V
�������������� ������������ ��ℎ��������
Gain constant
)
Output range
0.1 to 10.1 V
0.1 to 5.1 V
± 10 V
4 to 20 mA
± 10 V
1
) Ω
) − 0.001
��������
× �������� �������� mV/V
× �������� �������� mV/V
' shown in the connection diagrams above can be changed
gain
Resistor constant
�� = (
��������
(�������� − 1)
Gain constant
372
186
372
160
372
' as shown in Figure 2.2. This will
offs
in kΩ.
offs
) Ω
Resistor constant
40000
40000
40000
63200
40000