Chapter Two
Installation
man_105_2.9.doc
Page
17
The output circuit is connected to the appropriate pair of "DO" terminals. Each digital output
circuit includes a LED indicator which is lit when the digital output is active.
2.4.3
Digital Outputs (105-2, 105-3 and 105-4)
The digital outputs on the 105-2, 105-3 and 105-4 modules are transistor switched DC signals,
FET output to common rated at 30VDC 500 mA. The 105-2 provides one digital output; the 105-3
provides eight digital outputs and the 105-4 provides 4 – 16 outputs. The first four DO’s on the
105-3 and 105-4 modules are also the pulse outputs - that is, the first four DO's can be either
digital outputs or pulse outputs. The function of each of these outputs may be configured
individually. For a description of pulse outputs, refer to Section 2.4.7.
Digital outputs may be configured to individually turn off if no command message is received to
that output for a certain period. This feature provides an intelligent watch dog for each output, so
that a communications failure at a transmitting site causes the output to revert to a known state. See
Chapter 4
Configuration
for further details.
The output circuit is connected to the appropriate pair of "DO" terminals. Each digital output circuit
includes a LED indicator which is lit when the digital output is active.
2.4.4
Analogue Inputs (105-1 and 105-2)
The 105-1 module provides two 4 - 20 mA DC analogue inputs for connecting to instrument
transducers such as level, moisture, pressure transducers, etc. The 105-2 module provides six 0 -
20 mA DC analogue inputs. Note that the inputs on the 105-2 module will measure down to 0mA,
so they can also be used for zero based signals such as 0 - 10 mA.
Each analogue input has a positive and negative terminal, and may be placed at any point in the
current loop, as long as neither input rises above the 24 volt supply level. Each input has a loop
4-20mA
+
_
+24V
+AI
- AI
COM
105U
2-wire
Input
+
_
+24V
+AI
- AI
COM
105U
4-wire
Input
External
Power
Note:
AI must be within
27V of COM. If
terminal voltages
exceed this, a
loop isolator must
be used.
_
+
DO 1
DO 2
COM
105U
DC
Load
Max 30VDC
0.5A
