Mantracourt Electronics Limited
– ICA User Manual
9
Output Connections
The ICA5 analogue output is 4 to 20 mA. The power and signal are combined in a single pair cable, simplifying
installation.
N.B. Neither connection to the output load is electrically common to the load cell.
Output Shunt Resistance Formula – ICA4 and ICA5
The following formula gives the suitable range of shunt resistance (including the wiring resistance) for low supply
voltage operation of the ICA4H and ICA5. Alternatively, by transposing the formula the minimum supply voltage for a
given shunt resistance can be determined.
ICA4H
: the shunt resistance (input impedance of the receiver or monitor) and associated loop wiring must be less
than:
𝑉
𝑠𝑢𝑝𝑝𝑙𝑦
− 4
20 𝑚𝐴
− 𝑅
𝑤𝑖𝑟𝑖𝑛𝑔
ICA5S
: the shunt resistance must be less than:
𝑉
𝑠𝑢𝑝𝑝𝑙𝑦
− 7.5
20 𝑚𝐴
− 𝑅
𝑤𝑖𝑟𝑖𝑛𝑔
ICA5A
: the shunt resistance must be less than:
𝑉
𝑠𝑢𝑝𝑝𝑙𝑦
− 9
20 𝑚𝐴
− 𝑅
𝑤𝑖𝑟𝑖𝑛𝑔
Example 1
: ICA4H, assuming 5 ohm wiring resistance, 20 V supply
𝑉
𝑠𝑢𝑝𝑝𝑙𝑦
− 4
20 𝑚𝐴
− 𝑅
𝑤𝑖𝑟𝑖𝑛𝑔
=
20 − 4
0.02
− 5 = 795 Ω
Example 2
: ICA5S, assuming 10 ohm wiring resistance, 9 V supply
𝑉
𝑠𝑢𝑝𝑝𝑙𝑦
− 7.5
20 𝑚𝐴
− 𝑅
𝑤𝑖𝑟𝑖𝑛𝑔
=
9 − 7.5
0.02
− 10 = 65 Ω
