| Function The VAA-4E2A-G5-N/V2-Ex module is suitable for direct use in areas subject to the danger of explosion (Zone 1). The module itself is encapsulated (EEx m), while the connection technology for the AS-Interface-lead is designed for the increased safety category and the control circuits are designed to conform to EEx ia IIC. The VAA-4E2A-G5-N/V2-Ex module makes it possible to operate 4 sensors in accordance with IEC 60947-5-6 (NAMUR) or mechanical contacts and 2 intrinsically safe valves. Four variations are possible for connecting the sensors/mech. contacts (see electrical connection): Variant 1: Connection of NAMUR sensors, see connection assignment. Variant 2: If the mechanical contacts are wired according to the connection diagram, monitoring for lead breakage and short-circuit is possible. Variant 3: If the mechanical contacts are provided with only one 10 kn parallel resistor, the lead can be monitored for lead breakage. In this case, short-circuit monitoring must be turned off. Variant 4: No type of monitoring at all is available for this variant. In this case, lead breakage monitoring and short-circuit monitoring must be turned off. The Dip switches are located in the terminal compartment for sensor/valve connections (see the representation of the DIP switches). Lead breakage / short-circuit: Error monitoring is activated when the current in the control circuit I is less than 0.1 mA (lead breakage) or greater than 6 mA (short circuit). In this case the LED of the input in question and the LED PWR/CHK both flash red, and the module logs out from the AS-Interface. Note: If two channels are connected incorrectly, the output voltage may be reduced. To reset a module, it has to be disconnected from the supply. 2:1 Mode: The 2:1 mode enables any two sensors to be connected via a common 2-wire cable. Since in this mode the selection of the individual sensors is made via the polarity of the sensor supply, reverse polarity-protected sensors must be used for this operating mode. Sensors 1 and 3 form the first pair; sensors 2 and 4 the second. The sensors of a pair are connected anti-parallel to the module via a 2-wire cable. The first pair occupy terminals 12 and 32 (Sensor 1 + to terminal 32, Sensor 3 + to terminal 12). The second pair occupy terminals 22 and 42 (Sensor 2 + to terminal 42, Sensor 4 + to terminal 22). For mechanical contacts a serial diode is required for reverse polarity protection for operation in the 2:1 mode.The connection is made in the same sense as for the sensors (Contact 1 + to terminal 32, Contact 3 + to terminal 12, etc.). The 2:1 mode is activated via DIP switch 4 in the terminal compartment for the inputs and outputs. To activate and deactivate the mode |