Enter the range the transmitter is set to, then a current to get the value, or a value to get the current it should produce. Useful for commissioning a loop and for checking what a reading should be.
The transmitter maps the bottom of its range to 4 mA and the top to 20 mA. In between it is linear: value = low + (mA - 4) / 16 × (high - low). Sixteen milliamps of span carry the whole range.
A live zero separates a real minimum reading (4 mA) from a broken wire or a dead transmitter (0 mA). It also leaves the transmitter enough current to power itself on a two-wire loop.
Many transmitters signal a fault by driving the loop below about 3.6 mA or above about 21 mA. A reading outside 4 to 20 mA is worth treating as a fault rather than scaling it into a value.
Exactly half of the span. On a 0 to 10 bar transmitter it is 5 bar; on a -50 to 150 °C transmitter it is 50 °C.
Through a precision resistor: 250 Ω turns 4-20 mA into 1-5 V. Scale the voltage the same way, with 1 V as the bottom of the range and 5 V as the top.
Yes. Enter the value at 4 mA as the low end and the value at 20 mA as the high end, whatever their signs or order. The calculator follows the line between them.
Genesis reads RS485 Modbus sensors, analogue transducers and 1-Wire probes on the same four ports and reports them over cellular. Tell us what you need to read.
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