INTRODUCTION
WBPEEUI240757A0
2 - 1
SECTION 2 - DESCRIPTION AND OPERATION
INTRODUCTION
This section explains the output circuitry, control logic, data,
logic power and connections for the IMASO11 analog output
(ASO) module. The ASO module is an analog signal interface
between a multifunction processor (MFP) or multifunction con-
troller (MFC) module and process field devices. A control mod-
ule communicates with its I/O module on an I/O expander bus
as shown in Figure
. Each I/O module on the bus has a
unique address set by its address dipswitch (S1).
Analog output signals are either 1 to 5 VDC or 4 to 20 milli-
amps. The process requirements determine the output mode
(current or voltage). These signals, sent to the process, control
field devices.
MODULE BLOCK DIAGRAM
The ASO module circuits control the fourteen analog outputs
and transmit module operating status back to an MFP module.
Figure
is a block diagram illustrating signal flow through
the ASO module. Figure
shows the analog output circuit.
Analog Output Circuits
The analog output block consists of fourteen separate output
circuits that develop the analog outputs. They are closed loop
current/voltage output circuits that monitor and adjust the
output as compared to the D/A converter output demand. This
compensates for supply voltage variation and unknown load
Figure 2-1. Analog Output Module Block Diagram
I/O EXPANDER
BUS
LOGIC POWER
ANALOG
OUTPUTS (14)
T00941A
A/D
CONVERTER
FEEDBACK
SELECT
REFERENCE
MODULE
STATUS
D/A
CONVERTER
ANALOG
OUTPUT
P2
P3
P1
MODULE
STATUS LEDS
D/A
REGISTER
MODULE
MEMORY
CONTROL
LOGIC
I/O EXPANDER
BUS
INTERFACE
BUS FAULT
DETECTOR
1
8
OPEN
S1
