Dual Pulse Count Input Interface -

Description

The Model 2200A is a Pulse Count Input Network Node that is housed in a compact DIN rail enclosure. It allows integration of up to 2 digital pulse inputs into the LonWorks distributed digital network. Input devices such as relays, conditioned proximity sensors, conditioned capacitive sensors as well as ultrasonic sensors are all supported. The Model 2200A has a flexible front-end that supports direct wiring of NPN, PNP, TTL, as well as dry-contact type inputs. Pull-up resistor, pull-down resistor, threshold voltage, hysterisis voltage, and signal inversion can all be changed via configuration network variables. Added to the flexible hardware front-end is a very flexible firmware layer. The firmware simultaneously calculates the accumulated pulse count, frequency, and, for steady state signals, allows the discrete digital state to be read. The frequency measurement rate is in excess of 40 KHz and the accumulated pulse count can be up to 2,147,483,648. The pulse accumulator can be scaled in such a way as to allow multiple pulses to be counted as a single event. The frequency input can be averaged over multiple samples. Finally, to allow a smooth interface with LonWorks devices, the frequency and count data is also available as a percentage of a user-configurable range. Using the Model 2200A allows multiple sensors to be used over a simple four-wire bus installation. Two wires are used for power, the other are used for digital communication. The communication interface is the FTT-10 transceiver.