Gate input

An external input, “Gate”, for 24 V DC signals with a minimum pulse duration of t_ON > 1 µs is available and can be used as follows:

Lock counter value:
Lock the counter value via a positive or negative edge (index 0x80n0:04 “Gate polarity” = “Enable pos/neg. gate”)
Save counter value:
Save the counter value, in separate process data, via a positive or negative edge (output process data “Enable latch extern 2 on positive/negative edge” (0x70n0:0C/0D))

Lock counter value via a positive/negative edge at the gate input (Enable pos./neg. gate)

The level at the gate input at which the counter value is locked during runtime can be specified via index 0x80n0:04 “Gate polarity”.

0: Disable gate
The “Gate” input is disabled. It can still be used as “Latch extern 2” input.
1: Enable pos. gate
The counter value is locked with a HIGH level at the “Gate” input.
2: Enable neg. gate
The counter value is locked with LOW level at the “Gate” input.

The current level at the “Gate” input is displayed via process data “Status of input gate” (0x60n0:0C).

The “Gate” input may be used as a second latch input (Latch extern 2). To do this, the gate should be disabled.

	Deactivation of the gate Set the “Gate polarity” bit (index 0x80n0:04) to “0 – Disable gate” in order to be able to use the “Latch extern 2” input without locking the counter value after the latch event.

Process data “Enable latch extern 2 on positive edge” (0x70n0:0C) = TRUE
At the first external pulse with positive edge at the “Gate” input, the current counter value is stored in the process data “Latch value 2” (0x60n0:22).
Process data “Enable latch extern 2 on negative edge“ (0x70n0:0D) = TRUE
At the first external pulse with negative edge at the “Gate” input, the current counter value is stored in the process data “Latch value 2” (0x60n0:22).
Simultaneous activation of the bits in the process data “Enable latch extern 2 on positive edge” (0x70n0:0C) and “Enable latch extern 2 on negative edge” (0x70n0:0D)
When the first pulse is received at the “Gate” input–regardless of the polarity of the edge–the current counter value is stored in the process data “Latch value 2” (0x60n0:22).

Specification whether it is necessary to reactivate the command to save the counter value via:

“Enable continuous latch extern 2” Index 0x80n0:23 = FALSE
The following pulses at the “Gate” input have no effect on the latch value in the process data “Latch value 2” (0x60n0:22) when the bit in the process data “Enable latch extern 2 on positive edge” (0x70n0:0C) or “Enable latch extern 2 on negative edge” (0x70n0:0D) is set.
Only when the bit in the process data “Latch extern 2 valid” (0x60n2:12) is FALSE can a new counter value be written to the “Gate” input in the process data “Latch value 2” (0x60n0:22).
“Enable continuous latch extern 2” Index 0x80n0:23 = TRUE
The counter value is written to the process data field “Latch value 2” (0x60n2:22) each time a configured edge is detected at the “Gate” input.
There is no need to reactivate the bits in the process data “Enable latch extern 2 on positive edge” (0x70n0:0C) or “Enable latch extern 2 on negative edge” (0x70n0:0D).

The status of the input “Gate” can be recorded via the process data “Status of input gate” (0x60n0:0C).
Saving of the counter value in the process data “Latch value 2” (0x60n0:22) is confirmed by the bit in the process data “Latch extern 2 valid” (0x60n2:12).

	Simultaneous use of Gate and Latch extern 2 When using the index 0x80n0:04 “Gate polarity” (1 = “Enable pos. gate”) and simultaneous activation of the output process data “Enable latch extern 2 on positive edge” (0x70n0:0C), a positive edge on the “Gate” input first stores the current counter value in the input process data “Latch value 2” (0x60n0:22). After that, the counter value is locked. The same applies to the use of index 0x80n0:04 “Gate polarity” (2 = “Enable neg. gate”) and the simultaneous activation of the output process data “Enable latch extern 2 on negative edge” (0x70n0:0D) when a negative edge occurs at the “Gate” input.

	Multiple activation of the latch function If several commands are activated simultaneously to save the counter value in the “Latch value” process data (0x60n0:12), only the command that is set first is accepted by the terminal. The counter value is stored in the process data “Latch value” (0x60n0:12) at the next occurring event and confirmed with the corresponding bit. All other activated events are ignored. The counter value storage cannot be reactivated until all activated commands for latching the value have been deactivated. This also applies if they were activated after confirmation by the occurring event.