This facilitates sourcing up to four independently adjustable 4-20mA outputs from a single input, and these could be 4-20ma, 1-5V, 0-5V, or 0-10V as selected.
Model QLS sources up to four (4) independently adjustable 4-20 mA outputs from a single input, which can be 4-20 mA, 1-5V, 0-5V, or 0-10V, as selected by jumpers. The outputs can share a common ground.
The inputs and outputs are mutually isolated to +10V / -20V at 600 ohm load by means of active circuitry to accommodate differences in local grounds. If any device in an output loop is removed from the loop or fails, or if a wiring fault occurs, the other loops continue to operate properly. Each loop only drives a single load, avoiding compliance problems.
Model QLS overcomes problems of simply placing loads in series in a single 4-20 mA loop. In such a configuration, the devices in the loop cannot share a common ground, but must be electrically floating, which is often not possible. When any device in a single loop is removed, fails, or if a wiring fault occurs, all other devices in the loop lose their 4-20 mA signal. The transmitter voltage compliance limit may be exceeded, since the voltage drops across loads in series are additive.
The following diagrams explain the concept
