INTRODUCTION
I-E96-310B
2 - 1
SECTION 2 - DESCRIPTION AND OPERATION
INTRODUCTION
This section explains the digital output circuitry, control logic,
data, logic power, and connections for the IMDSO01, IMDSO02
and IMDSO03 Digital Output Module (DSO). The DSO module
is a digital signal interface between a control module
(multi-function processor module, multi-function controller
module, or logic master module) and process field devices. The
control module communicates with its DSO module on the I/O
expander bus as shown in Figure
. Each DSO module on
the I/O expander bus has a unique I/O expander bus address.
The address of a DSO module is set by dipswitch S1.
DIGITAL OUTPUTS
Digital signals have two states, on or off. The DSO digital out-
puts switch voltages of 24 to 240 VAC (IMDSO01 module), four
to 60 VDC (IMDSO02 module) or five to 160 VDC (IMDSO03
module). These voltages energize (turn on) or de-energize (turn
off) field devices. The type of process field devices determines
which DSO module to use.
FUNCTIONAL BLOCK DIAGRAM
The DSO module consists of registers, buffers and interface
circuits. They control the digital output switching and transmit
operating status to a control module. Solid state relays provide
the switching functions. Figure
is a block diagram of the
DSO module. It illustrates signal flow through the module.
Digital Output Circuits
The digital output block consists of eight solid state relays that
function as digital output switches. The digital output block
also includes fuses that protect the module circuitry and field
devices from current surges and short circuits. Each of the
three DSO module variants have different output switching
capabilities and fusing. The solid state relays on a DSO module
determine the voltage switching capability of that module. All
the relays are normally open or de-energized until a signal
from the data selector block causes the relay circuit to close or
energize. Figure
shows the digital output circuit.
The data selector block drives the solid state relays. It uses
data from the output register or default register to open or
