8B modules are an optimal solution for monitoring real-world process signals and providing high-level signals to a data acquisition system. Each 8B45 module isolates and conditions a frequency input signal and provides an analog voltage output.
The frequency input signal can be either a TTL level or zero crossing with as little as ±100mV amplitude. Input circuitry for each signal type has built-in hysteresis to prevent spurious noise from corrupting the module output. TTL signals are applied to the + and – terminals while zero crossing signals are applied to the +EXC and – terminals. Reference the block diagram below.
A 5V excitation is available for use with magnetic pick-up or contact closure type sensors. The excitation is available on the –EXC terminal with return on the – terminal.
A special input circuit on the 8B45 module provides protection against accidental connection of power-line voltages up to 240VAC. Clamp circuits on the I/O and power terminals protect against harmful transients.
Isolation is provided by optical coupling to suppress transmission of common mode spikes or surges. The module is powered from +5VDC, ±5%.
The modules are designed for installation in Class I, Division 2 hazardous locations and have a high level of immunity to environmental noise.