MAN0878-09-EN_XLE_XLT_UserManual
A u g u s t 2 3 , 2 0 1 8
P a g e 75 | 158
Protection for Inductive Loads
–
Inductive loads can cause reverse currents when they turn off
that can shorten the life of relay contacts. Some protective measures must be determined by
an engineer. Below are some recommendations that will work for many applications. If there
are additional questions on protection from inductive load, consult an application engineer or
HEAPG Technical Support.
DC Loads
–
General purpose diode (IN4004) in reverse bias across the load.
AC Load
–
MOV (Harris V140xxx for 120V, V275xx for 220V)
Output State on Controller Stop
When the controller is stopped the operation of each output is configurable. The outputs can
hold the state they were in before the controller stopped or they can go to a predetermined
state. By default, relay outputs turn off. For more information on stop state, see configuration
(
Chapter 15
) for Cscape settings.
11.6
Digital Inputs
NOTE: See
Chapter 1
2
for high speed I/O information and refer to the datasheet for XLE/XLT
model being used for details on jumper settings.
NOTE
:
The digital inputs on the XLE/XLT are designed for low voltage DC inputs. The inputs are
designed to support both positive and negative input modes. The mode is set by a jumper setting
and a configuration parameter in Cscape. All the inputs on the unit must be configured to the
same mode.
Figure 11.5
–
Positive and Negative Inputs
In positive logic mode, a positive voltage applied to the input will turn the input
‘On’
. The internal
design of this mode is basically a resistor from the input to I/O ground. This mode is sometimes
called sourcing.
In negative logic mode, connecting the input to the I/O ground or zero volts will turn the input
‘O
n
’
. The internal design of this mode is basically a resistor from the input to the positive I/O
voltage (usually 12 or 24V). This mode is sometimes called sinking. Some of the digital inputs
may support high speed input functional such as counting or frequency measurement.
I1
0V
001XLE036
12-24VDC
I1
0V
Positive Logic In Negative Logic In
Positive Logic vs. Negative Logic Wiring
The XLE/XLT can be wired for Positive Logic inputs or Negative Logic inputs.
