At a Glance
In order to check the discrete I/O connection, ensure that:
sensor data is registered by the corresponding inputs and by the processor
control orders from the processor are registered by the outputs and transmitted to the corresponding pre-actuators
| WARNING | |
|---|---|
UNEXPECTED EQUIPMENT OPERATION Active outputs can activate machine movements. All power must be turned off before this check
is carried out: 1. remove power fuses from the motor
controls 2. turn off the power of hydraulic and
pneumatic units 3. power up the PLC fitted with its
Discrete I/O modules Failure to follow these instructions can result in death, serious injury, or equipment damage. | |
Description
After this, it is possible to check the connection of the Discrete I/O modules:
without a terminal: activate each sensor and check whether the corresponding input LED changes. If it remains unchanged, check the wiring and correct operation of the sensor.
with a terminal (more in-depth check on the connection of the inputs/outputs). An application with configured I/Os in the PLC is required, even if it is empty (in that case, do not declare any module in the ‘FAST task’).
This check can be carried out with the PLC in RUN mode, from a PC equipped with Control Expert software giving access to debug functions.
This check can also be carried out with an entire application loaded in the memory. In this case, stop the processing of the program by de-activating the MAST, FAST and event tasks by setting system bits %S30, %S31, and %S38 to 0.
Input Check
The following table shows the procedure for checking input connections.
Step |
Action |
|---|---|
1 |
Activate each sensor and check that the corresponding input LED changes status. |
2 |
Check on the terminal screen that the corresponding input bit (%I•) also changes status. |
Output Check
The following table shows the procedure for checking output connections.
Step |
Action |
|---|---|
1 |
From the terminal, set each bit (%Q•) that corresponds to an output to 1 then 0. |
2 |
Check that the corresponding output LED turns on then off and that the corresponding pre-actuator activates then de-activates. |