Background information: Although digital I/O signals are basically less sensitive to external noise than for example serial data signals due to their lower bandwidth and the large voltage span, application conditions still sometimes require transmission procedures which are completely resistant to noise impinging on the transmission line.
Glass fiber optic cables used as the transmission medium meet these requirements in ideal fashion and also offer the advantage of galvanic isolation of up to virtually any value between the connected devices. In installations which are subjected to high risk of lightning strikes, for example in outdoor locations or between distant buildings, such a solution ensures that the connected components will survive even under adverse conditions.
The W&T Digital-I/O Extender Set 8x8 is fully implemented in hardware, so that there is no principle risk of malfunction caused by hidden firmware errors or by a system crash.
The functionality of the fiber optic connection is cyclically monitored. The status of the connection is indicated by an LED and a switching output. In addition, the default status of the digital outputs can be individually configured for each output in case of failure of the fiber optic line.
Technical data:
Transmitted signals:
16 digital signals (eight in each direction)
I/O connection:
Plug-in screw terminal
Digital outputs:
8 x Digital Out 8V-30V, 500mA, short circuit protected, configurable response when fiber optic connection fails
Digital inputs:
8 x Digital In, max. input voltage ±30V, protected against reverse connection within this range, Switching threshold 9V +/- 1V, "On" current = 2.2 mA
