58
Rockwell Automation Publication 871TM-UM002C-EN-P - October 2017
Chapter 9
Review the 1734-4IOL IO-Link Add-on Profile
Polarity
The 871TM sensor features the ability to change the output switching mode.
The factory default mode is Not Inverted (normally open). With the sensor in
IO-Link mode, you can change the polarity parameter to Inverted (normally
closed). The sensor cannot operate in Inverted (normally closed) mode while
operating in IO-Link mode. Therefore, to use the Inverted (normally closed)
functionality, the sensor must be disconnected from IO-Link and used as a
standard input/output (SIO) device.
If you want to change the sensor back to “Not Inverted” (normally open), you
must connect the sensor back to the IO-Link master and change the setting
under the polarity parameter.
Switching Timer Mode
The switching timer is a useful function for manipulating the output of the
sensor in relation to timing. It is useful for precision applications where the
output of the sensor must be precisely triggered at a certain time. It is important
to note that the lowest time base must be used and that there is a tolerance error
of approximately ±15%.
The 871TM sensor uses a time base with an associated offset value along with a
multiplier to create a delay value when using the switching timer mode
function. It is important that the smallest time base and multiplier is used to
create the delay. By using the smallest time base and multiplier, the tolerance
error of ±15% can be reduced. An example is provided to understand the
relationship between the different input values. The maximum delay that can
be entered is 537.6 ms.
Desired Time Delay= (Time Multiplier) (Time Base) + Offset Value
For example: To achieve a delay of approximately24 milliseconds, you must use a
time base of 1 (0.4 ms) and 44 milliseconds for a timer base multiplier. This value
does not factor in the tolerance error of ±15%.
24 ms = (44) (0.4) + 6.4 ms
IMPORTANT
The enable parameter must be ON to enable the switching timer mode.
Time Base
Offset Value (ms)
Timer Multiplier (ms)
0 = 0.1 ms
0
0…63 ms
1 = 0.4 ms
6.4
2 = 1.6 ms
32
3 = 6.4 ms
134.4