2.4 Functions¶

Switch-off filter¶

Block diagram — Switch-off filter

This block can delay the 1→0 flank of the input signal for a specified amount of time. The input signal must be low for the specified Filter time for the output to turn off.

Warning

This block increases the maximum reaction time of safety functions.

Timing diagram — Delay OFF block with Delay OFF = 20 ms

A Delay OFF block configured with Delay OFF = 20 ms. It has no delay on. The 0→1 flank passes right through the block, while the 1→0 flanks are delayed for the specified amount (here 20 ms). Note that the first 1→0→1 pulse on the input does not turn off the output, as the output requires the input to be low for at least the specified Delay OFF time before it turns off.

Inputs

Input — the input signal to delay the 1→0 flank of.

Outputs

Output — the delayed signal.

Properties

Name — changes the name of this block.
Filter time — the time in milliseconds to delay the 1→0 flank of the input signal.

Switch-on filter¶

Block diagram — Switch-on filter

This block can delay the 0→1 flank of the input signal for a specified amount of time. This can be used to filter away signal pulses that are shorter than the specified Filter time, since the input is required to be 1 (HIGH) for the specified Delay ON time for the output to go to 1 (HIGH).

Figure 2.2 — Timing diagram for a Delay ON block with Delay ON set to 20 ms

Figure 2.2: Timing diagram for a Delay ON block with Delay ON set to 20 ms. The block has no delay off. Note that the first pulse on the input does not turn the output high, as it requires the input to be high for longer than 20 ms.

Inputs

Input — the input signal to delay the 0→1 flank of.

Outputs

Output — the delayed signal.

Properties

Comment — changes the comment text above this block.
Filter time — the time to delay the 0→1 flank of the input signal.

Reset¶

Block diagram — Reset

This block can be used to reset a safety device input, or some other signal that needs reset confirmation. To turn on the output, the input must receive a constantly high signal, and the reset must receive a 0→1→0 pulse, where the signal is 1 (HIGH) for longer than the specified Min Push Time milliseconds. If the input signal goes low at any time during or after the reset operation, the output turns off. The lamp output outputs a standard reset push button indication signal (about 1 Hz when the input is high), that can be connected directly to the Indication input of a push button block.

The allow_reset input is an optional input. If this input is enabled, it requires a constant 1 signal during the reset operation. The state of this input is only monitored when the run output is 0. This input should be used when the reset signal is coming from another node in the system.

Timing diagram — Reset

Inputs

Input — where the signal that should be reset is connected. If this goes low at any time during or after the reset operation, the output will go low.
Reset — must receive a 0→1→0 flank sequence for the output to turn on.
Allow_reset (optional) — must be 1 during the reset sequence for the reset to be valid.

Outputs

Output — turns on if a valid reset sequence is received on the Reset input and the Input is 1 (HIGH). If the Input goes low at any time, the output turns off.
Lamp — indication signal that can be used for indication.

Properties

Name — changes the name of this block.
Allow Reset — enables/disables the allow_reset input.
Enable Lamp Output — enables or disables the Lamp output connector.
Minimum push time — the reset input must be pressed for at least this time for the reset to be valid and the output to go high.

Sequence Reset¶

Block diagram — Sequence Reset

This block can be used for resetting functions that require several reset operations in sequence. It is constructed so that some reset buttons can be "inside" an enclosure. This means that during the reset of the inside buttons, the Input can go low. This is because if, for example, there is a gate that needs to be reset and there are reset buttons inside the enclosure, the gate must be opened to enter the enclosure and press the buttons, and then opened again to leave the enclosure. After resetting the first outside button, the input must be 1 (HIGH) for the rest of the reset operation. If the input goes low during this time, the whole reset operation must be repeated from the beginning.

Inputs

Input — the input signal that needs to be reset.
Reset Inside 0–8 — these inputs allow the Input signal to go low during the reset operation.
Reset Outside 1–8 — these inputs do not allow the input signal to go low during operation.

Outputs

Output — after the reset operation is complete, this output goes to 1 (HIGH). If the input turns off, the output goes to 0 (LOW) and a new reset operation must be completed to start again. During the "inside" part of the reset function, the door input state is ignored.
Lamp Inside/Outside (0–8) — connect these outputs to the lamp inputs of the corresponding push buttons.

Properties

Name — changes the name of this block.
Minimum push time — the minimum time a reset input must be high to count as a valid reset.
Max Time Between — the maximum time allowed between two reset operations. If this time is exceeded, the reset operation must be restarted from the beginning (the first button).
Buttons Inside — specifies how many buttons should be inside (minimum 0, maximum 8). If this is set to 0, only outside reset buttons will be used.
Buttons Outside — specifies how many buttons should be outside (minimum 1, maximum 8).

Max Time¶

Block diagram — Max Time

This block creates a pulse of a specified maximum length, from a 0→1 flank on the input. It ensures that the output is never high for longer than the specified Max Pulse Length time. After a pulse has been generated, another one cannot be generated until the specified Min Low Time (ms) has passed. If the input goes low before the specified Max Pulse Length time has passed, the output goes low and another pulse cannot be generated until the specified Min Low Time has passed.

Inputs

Input — the input that should generate the pulse.

Outputs

Output — outputs the generated pulse.

Properties

Name — changes the name of this block.
Min zero time — requires the input to be low for at least this time before a new pulse can be generated.
Max pulse length — the maximum length of the pulse. The pulse is never longer than this.

Synchronize Inputs¶

Block diagram — Synchronize Inputs

This block can be used to combine several signals as an input internally. The function behaves the same way as a regular input function, but instead of using physical pins on the device it uses internal signals. This can be used, for example, to synchronize two separate two-hand device inputs operated at two different locations to ensure that they are pressed within a certain time, or to synchronize two or more global memories from other units.

Note

See 1.15 Input Functions and Advanced Input (2.1) for descriptions on how the input function works.

Figure 2.3 — Two Two-hand device inputs synchronized using an Internal Input block

Figure 2.3: Two Two-hand device inputs synchronized using an Internal Input block. This synchronizes the inputs. Figure 2.3 describes how to connect two Two-Hand Device inputs to an Internal Input to synchronize them. This ensures that both are pressed within a certain time of each other. If one is released, both must be released and pressed to restart the function again.

Inputs

1–16 — the inputs to use in the function.

Outputs

on — outputs 1 (HIGH) if the function is in the ON-state. Outputs 0 if the function is in the OFF-state.
error — outputs 1 (HIGH) if the function is in the ERROR-state.

Properties

Name — changes the name of this block.
Enable ERROR Output — enables the ERROR output connector.
StartUp Test — enables or disables the StartUp test check. If StartUp Test is enabled, the function cannot go to the ON-state directly at start-up (power on) but needs a valid OFF-state first.
Filter ON — filters the 0→1 flank of the inputs.
Filter OFF — filters the 1→0 flank of the inputs.
Simultaneity — all pins must go to the ON-state within this time for the function to go to the ON-state. If this criterion fails, the input needs all pins to go to the OFF-state before a new attempt can be made.
Enable Zero Time — enables or disables the Zero Time property.
Zero Time — if enabled, requires all pins to be in the OFF-state for this time before the function can go to the ON-state.

Pulse Counter¶

Block diagram — Pulse Counter

This block counts 0→1 transitions on the input. When the number of pulses detected is equal to the specified number of pulses in the block settings, the output turns on. The count is reset back to 0 if the reset input turns on. When the reset input is disabled, the count is reset when the next pulse is detected on the input.

Note

A pulse must be at least 3 ms long to be guaranteed to be detected by the block.

Note

If the reset input gets a high signal, the count is reset to 0 even if the output is not turned on.

Inputs

Input — the input where 0→1 transitions are counted.
Reset (optional) — if enabled, when a 1 is detected on this input, resets the count to 0 and turns off the output.

Outputs

Output — outputs 1 (HIGH) if the number of pulses detected on the input equals the number specified by the Pulses block setting.

Properties

Name — changes the name of this block.
Enable reset — enables/disables the reset input.
Pulses — specifies how many pulses should be counted before the output turns on.