User Manual UMAX030541. Version V1 7-116
1.2.
Digital Output Function Block
There are two types of universal output function blocks, one for the digital outputs and the
other for the analog outputs. While both types of function blocks are driving the same
outputs, they are just treated as separate function blocks here for ease of explanation.
The digital output (DO) function block only becomes applicable on the output when object
6310h
, AO Output Type
, is set to
Digital ON/OFF
output response (Type=1000).
Several other objects are associated with the Analog Output function block and will be
explained in detail in section 1.3. Therefore, this section will only elaborate on the objects
unique to the DO function block.
An output can be controlled either by an on-board control signal (such as the result from
a lookup table function) or a CANopen® object that has mapped to an RPDO. In the case
of an output configured for a digital response, when a CANopen® Message has been
selected as the 2340h
AO Control Source
(see Table 5), data from the appropriate sub-
index from the write-mappable object 6220h
DO Write State
will be used as the control
signal.
The Enable and Override Inputs and Responses for a digital output are the same as for
an Analog Output and are evaluated in the same order. Therefore, what will be described
in section 1.3 for these also applied for the DO function block.
As with the AO function, the output will respond to the Control Input if and only if the
following conditions have been met:
a) No fault is detected for any of the control signals
b) The override command is either ignored or false (Override Input)
c) The output has not been disabled by a secondary signal (Enable Input)
When the output is being driven by the Control Input, the state is logically set to OFF while
the Control Input is zero and is set to ON whenever a non-zero value is written. By default,
Normal On/Off
logic is used. The
resulting “DO Drive State” will depend on the object
2241h
DO Polarity
, as per Table 1.
Value
Meaning
DO Logic State
DO Drive State
0
Normal On/Off
OFF
OFF
ON
ON
1
Inverse On/Off
OFF
ON
ON
OFF
2
Latched Logic
ON to OFF
No Change
OFF to ON
State Change (i.e. OFF to ON)
3
Blinking Logic
OFF
OFF
ON
Toggling OFF and ON at the rate defined
in object 2223h
DO Blink Rate
(in ms)
Table 1
– DO Polarity Options
