Analog outputs
Analog output applications
You can use an analog output to send a signal to an external analog input, for example an analog-controlled valve, to modify a water pipe’s valve position to change the flow rate.
For analog output operation, your meter takes an input value and scales it to the appropriate signal value to send out the physical analog output port.
Your meter’s analog I/O option modules can output either low voltage or current using standard analog transducers such as 4–20 mA current transducers.
Analog output behavior
Your meter’s analog output, after it is configured, outputs voltage or current signals. If your meter’s analog output source becomes unavailable (N/A) the analog output level should go to zero (0 V/0 mA) under most conditions.
When your meter is powered off or configured to send voltage, the meter registers as a high impedance.
The electrical signal on the analog output is DC; make sure proper polarity is observed when wiring external devices to the analog output ports.
Analog output zero scale and full scale values
In most cases, your meter’s analog output range matches the range of the analog sensors that your meter’s outputs are connected to. In that case, your meter’s analog output zero scale and full scale values are the maximum and minimum values of the source driving your meter’s analog output. These values are used to normalize the source value to a value between 0 and 1 which is applied to the operating range of the analog output port to determine the analog output current or voltage. For example:
| Source value | Analog output register values | Meter’s analog output signal |
|---|---|---|
0–120 kW range 100 kW | Full scale = 120 (kW) Zero scale = 0 (kW) Normalized: 0.83 | 4–20 mA range Output: 17.33 mA |
0–120 kW range 100 kW | Full scale = 120 (kW) Zero scale = 0 (kW) Normalized: 0.83 | 0–20 mA range1 Output: 16.67 mA |
1 Analog I/O option module must have firmware version v1.2 or later.
If your meter’s analog output range does not match the range of the connected analog sensor, you must calculate the full scale and zero scale values by analyzing the system.
For more information see Analog Output Module in ION Reference Help.