Zero pulse C input

With incremental encoders, a full revolution is marked by a special marker, the zero pulse C. This pulse can be used in the terminal as follows:

Counter value reset: The counter value is reset to the value specified in Index 0x80n1:1B “Reset counter value” (default setting: “0”)
(index 80n0:01 “Enable C reset”)
Set counter value: the counter value is set to a predefined value (output process data “Set counter on latch C”)
Save counter value: the counter value is saved in the latch register (output process data “Enable latch C”)

The “Status of input C” input process data 0x60n0:0B displays the current level at the zero pulse C input.

	Status of input C Zero pulse C has only a short pulse duration, depending on the rotational speed. Due to the cyclic request, it is possible that the HIGH level of the zero pulse is not transferred congruently into the process data “Status of input C” (0x60n0:0B).

Counter value reset via the zero pulse C input (Enable C reset)

The counter value can be set to the value specified in index 0x80n1:1B “Reset counter value” for every full revolution of the encoder via the zero pulse C.

Presetting of the reset value via index 0x80n1:1B “Reset counter value” (Default: 0)
To activate this function set the bit in index 0x80n0:01 “Enable C reset”.
There is no status message via the process data.

Set counter value via input zero pulse C (Set counter on latch C)

The counter value can be set to a preset value during runtime via the process data by means of the zero pulse C.

Setting the counter value using the process data “Set counter value” (0x70n0:11)
Activation of the counter value setting via zero pulse C:

Process data “Set counter on latch C” (0x70n0:08) = TRUE
At the next zero pulse, the counter value (Counter value) is set to the counter value specified in the process data “Set counter value” (0x70n0:11).

To confirm, the bit in the process data “Set counter done” (0x60n0:03) is set to TRUE.
The count value preset can only be reactivated via the zero pulse C once the bit in the process data “Set counter on latch C” (0x70n0:08) has been set to FALSE.

	Multiple activation of “Set counter on ...” If several commands are activated to accept the preset counter value, only the command that is set first is accepted by the terminal. All other commands are ignored but remain activated, depending on the system. The counter value is set to the preset counter value at the first activated event and confirmed by the bit in process data “Set counter done” (0x60n0:03). The counter value specification cannot be reactivated until all activated commands for the transfer of the counter value have been deactivated. This is confirmed by setting the bit in process data “Set counter done” (0x60n0:03) to FALSE.

Save counter value via the zero pulse C input (Enable latch C)

The counter value can be stored at runtime via the process data and the zero pulse in “Latch value” (0x60n0:12).

The function is activated by setting the bit in process data “Enable latch C” (0x70n0:01) to TRUE.
The current counter value is saved in the process data “Latch value” (0x60n0:12) with the next zero pulse at input C. The subsequent pulses have no influence on the latch value.
The bit in process data “Latch C valid” (0x60n0:01) is set to TRUE.
After reactivating the process data “Enable latch C” (0x70n0:01) a new counter value cannot be written to the Latch input until the values of the “Enable latch C” bit (0x70n0:01) and the “Latch C valid” bit (0x60n0:01) are FALSE.

	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.