SIL 3 DIGITAL OUTPUT DRIVER, NE LOADS, LOOP POWERED
DESCRIPTION
The single channel Loop Powered Digital Output Isolator, D5048S, is suitable for driving solenoid valves, visual or audible alarms to alert a plant operator, or other process control devices in Hazardous Area from a driving signal in Safe Area. It can also be used as a controllable supply to power measuring or process control equipment.
Its use is allowed in applications requiring up to SIL 3 level (according to IEC 61508) in safety related systems for high risk industries.
The Safety PLC or DCS driving signal powers the field device through the D5048S, which provides isolation and is capable of monitoring the conditions of the line.
Short and open circuit diagnostic monitoring, dip-switch selectable and active when input power is present, provides LED indication and NC transistor output signaling.
When fault is detected output is de-energized until normal condition is restored.
Line short and open output circuit fault detection is also reflected on the PLC / DCS input circuit providing less than 10 mA consumption. In alternative, input impedance can be set to be always lower than 2 kΩ.
An override input, dip-switch selectable, is provided to permit a safety system to override the control signal. When enabled, a low input voltage always de-energizes the field device regardless of the input signal.
Three basic output circuits are selectable, with different safety parameters, to interface the majority of devices on the market. The selection among the three output characteristics is obtained by connecting the field device to a different terminal block.