Specifications

The D1000 series features versatile digital I/O capability to interface to
auxiliary equipment. The functions available are:
1) Digital Outputs
2) Digital Inputs
3) Alarm Outputs
4) Events Counter
Digital Outputs
A digital output consists of an open-collector transistor controlled by the
host, using the Digital Output (DO) command (See Figure 6.1). The
number of digital outputs implemented depends on the specific D1000
model number. Most sensor modules contain two digital outputs and the
D1701/2 has eight digital outputs. The open-collector configuration is used
to provide maximum versatility in interfacing to solid state relays (SSR’s)
or to standard logic levels such as TTL or CMOS. Each digital output can
sink up to 30mA and can withstand up to 30V. Power in the transistor must
be limited to 300mW. The emitter of each transistor is tied to the GND
terminal on the input connector.
Chapter 6
Digital I/O Functions
Figure 6.1 Digital Outputs Used With Relays
A typical connection of a digital I/O output is shown in Figure 6.1. In this
case, a solid state relay is controlled by the D1000 module. The SSR can
then be used to control AC power to alarms, heaters, pumps, etc. A typical