Measurement Computing ZonicBook 618E rev.3.4 - Manual (Page 78)

Each digital output has an open-drain DMOSFET (Double-diffused Metal Oxide Semiconductor Field
Effect Transistor) that can sink up to 150 mA and is capable of directly driving relays.
Digital Output Schematic
*The digital out connection, shown for channel 2 only, is typical of all 8 channels.
The digital output port can be read back as part of the scan group of an acquisition.
Note: When a channel is set for Digital Input, its DMOSFET is “OFF.”
An external driver can drive any of the digital bits high or low, as long as the channel is in the Digital Input
mode, i.e., the DMOSFET is “OFF.”
The digital outputs can be directly updated by application software at any time. The digital output port has
an 8-bit Mask byte associated with the digital update byte. The output port will be updated if the
corresponding bit in the Mask byte is a 1. Otherwise the output port bit will be left unchanged.
The digital outputs can be updated based on the condition of any input channel value(s). Up to 16 set
points (each with two 16-bit compare values, an 8-bit digital output port byte, an 8-bit mask byte, and a
control byte) can be assigned to a channel.
When a set point has been programmed the two 16-bit values are compared [in real-time] to the measured
value for that channel. When the comparison condition is met, the output port is updated instantaneously.
Valid conditions include greater than value, less than value, inside the window, and outside the window.
With a total of 16 setpoints per channel complex updating schemes can be defined to meet the most
demanding application requirements.
Reference Note:
For detailed documentation regarding software and Digital I/O you will need to refer to one or
more of the following, as applicable. A PDF version of each is included on the installation CD.
¾ eZ-TOMAS User’s Manual
¾ eZ-NDT User’s Manual
9-2 Digital I/O 929195 ZonicBook/618E