Safety Input Modules in CIP Safety Systems

The following apply to the safety inputs:
  • You can connect safety devices, such as Emergency Stop Push Button, gate switches, and safety light curtains.
  • An external wiring short-circuit check is possible when inputs are wired in combination with test outputs. The module must be wired in combination with test outputs when this function is used.
  • Independently adjustable on and off delays are available per channel.
  • If you configure inputs as Safety Pulse Test, you must choose a test source.
  • Diagnostics. See Point Diagnostics.
  • Safety input points are configured as the following:
    • Not Used
    • Safety Pulse Test
    • Safety
The following apply to the test outputs:
  • Test outputs can be configured as the following:
    • Not Used
    • Standard Output
    • Pulse Test
    • Power Supply
    • Muting Lamp
  • Separate test outputs are provided for short-circuit detection of a safety input (or inputs).
  • Can supply 24V DC power to devices, such as safety sensors.

Use Test Output with a Safety Input

A test output can be used in combination with a safety input for short circuit and cross-channel fault detection.
Configure the test output as a pulse test source and associate it to a specific safety input. The associated safety input must use a Point Mode = Safety Pulse Test.
One test output can be assigned to a maximum of four safety inputs.
Test Pulse in a Cycle
On the safety input modules, the pulse width (X) is less than 700 μs; the pulse period (Y) is less than 524 ms.
When an external contact is closed, a test pulse is output from the test output terminal to diagnose the field wiring and input circuitry. By using this function, short circuits between inputs and power supply (positive), and between input signal lines can be detected. However, a short circuit between two input channels cannot be detected if these two channels correspond to the same Test Output. For example, you associate Test Output 0 to Safety Input 0 and 7. If these two channels short circuit, it cannot be detected.
Short Circuit Between Input Signal Lines

Single-channel Mode

If an error is detected on the input channel, Safety Input Data and Safety Input Status change to the off state.
Normal Operation and Fault Detection (Not to Scale)

Safety Input Fault Reset

The I/O channel supports a module-level user-configurable ‘Latch Fault until Reset via Output Tag’ mode and recovers from a Safety Input Short Circuit fault.
TIP:
Other types of Safety Input faults are non-recoverable. You must cycle power to the module.
Latch Fault until Reset via Output Tag mode is Enabled
When Latch Fault mode is Enabled, the I/O channel holds safety input fault indications until it checks that the fault is removed. If the fault is removed, the channel clears the fault status only upon detecting that the ResetFault in its consume assembly channel sees a transition from 0 to 1.
Latch Fault until Reset via Output Tag mode is Disabled
When Latch Fault mode is Disabled (default), the I/O channel holds safety input fault indications for 1 second until it checks if the fault is removed. If the fault is removed, the channel clears the fault status only upon detecting the safety input is low on the screw. If not, the channel continues to check if the fault is removed.

Safety Input Delay Time

You can increase the time that it takes for an input point to transition from On to Off and Off to On. The increase in time is a delay of the signal from the module to the controller.
The delay time is added to the RPI. For example, if you set the RPI at 10 ms and use an input delay time of 2 ms, the signal from the module to the controller is 12 ms.
When chattering or low frequency noise coupling is present on the input signal, an increase in the time it takes to transition from one state to another improves noise immunity within a signal.
Off to On Delay Time
Description
Transition Delay Times
Diagram
An input signal is treated as Logic 0 during the Off to On delay time after the rising edge of the input contact.
The input turns on only if the input contact remains on after the Off to On delay time has elapsed. This setting help prevent rapid changes of the input data due to contact bounce.
  • 0 ms
  • 2 ms
  • 5 ms
  • 10 ms
  • 20 ms
  • 50 ms
On to Off Delay Time
Description
Transition Delay Times
Diagram
An input signal is treated as Logic 1 during the On to Off delay time after the falling edge of the input contact.
The input turns off only if the input contact remains off after the On to Off delay time has elapsed. This setting helps to prevent rapid changes of the input data due to contact bounce.
  • 0 ms
  • 2 ms
  • 5 ms
  • 10 ms
  • 20 ms
  • 50 ms
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