Emerson PACSystems RSTi-EP function modules are available to meet specific system needs:

Digital Pulse Width Modulation (PWM): PWM modules use positive logic to control small motors and valve flaps. The switching frequencies are adjustable up to 40kHz and the push/pull output levels can be used for motor activation and change of rotation direction. Available in two current requirement options, 0.5 (EP-5422) or 2A (EP-5442).

High-Speed Counter: Choice of 1- or 2-channel 32-bit counter with maximum input frequency of 100kHz (Pulse & direction or A/B mode with 1-, 2-, or 4-times sampling). Input filter time is adjustable from 0.01 to 1ms. They also feature an alarm and diagnostic function with μs time stamp.

Frequency Measurement: The EP-5212 can read frequency of one square-wave signal from one or two external sensors with a maximum input frequency of 100kHz. It features a digitally adjustable input filter to suppress interference (17 filter frequencies gradually adjustable between 3Hz and 187kHz).

SSI Encoder: Interface module that can read differential signals (RS422) from an SSI encoder. It can be connected as a master directly to the encoder, providing the clock. Data can be formatted as binary or reflected binary (Gray code) and has a transfer rate of 125kHz to 2MHz.

Serial Communications: Serial data can be exchanged between the PLC and a data terminal device using the EP-5261 communication module. The device (such as a barcode scanner or printer) can be connected through an interface type RS232, RS485, or RS422. The data transfer rate can be set between 300 and 115,200 bps.