Gate/Latch input
The terminal provides an external Gate/Latch input for 24 VDC signals with a minimum pulse duration of tON > 1 µs. This can be used as follows:
- Lock counter value:
lock the counter value via a positive or negative edge (Enable pos/neg. gate) - Save counter value:
save the counter value in separate process data via a positive or negative edge (Enable latch extern 2 on positive/negative edge)
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/Latch input is disabled. It can still be used as Latch extern 2 input. - 1: Enable pos. gate
The counter value is locked with HIGH level at the Gate/Latch input. - 2: Enable neg. gate
The counter value is locked with LOW level at the Gate/Latch input. - The current level at the Gate input is displayed via process data 0x60n0:0C "Status of input gate".
Save counter value via a positive/negative edge at the Gate/Latch input (Enable latch extern 2 on positive/negative edge)
The terminal offers the option of using the Gate/Latch input as a second Latch input (Latch extern 2). To do this, the gate should be deactivated.
 | 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 disabling the counter value after the latch event. |
- The counter value at the Latch extern 2 input can be saved via:
- Index 0x70n0:0C "Enable latch extern 2 on positive edge" = TRUE
The current counter value is stored in index 0x60n0:22 "Latch value 2" at the first external pulse with positive edge at the Gate/Latch input. - Index 0x70n0:0D "Enable latch extern 2 on negative edge" = TRUE
The current counter value is stored in index 0x60n0:22 "Latch value 2" at the first external pulse with negative edge at the Gate/Latch input. - Simultaneous activation of 0x70n0:0C and 0x70n0:0D
The current counter value is stored in index 0x60n0:22 "Latch value 2" at the first pulse at the Gate/Latch input, independent of the edge polarity. - 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/Latch input have no influence on the latch value in index 0x60n0:22 "Latch value 2" when the bit in index 0x70n0:0C or 0x70n0:0D is set.
A new counter value can only be written to the Gate/Latch input in index 0x60n0:22 "Latch value 2" if index 0x60n2:12 "Latch extern 2 valid" is FALSE. - "Enable continuous latch extern 2" Index 0x80n0:23= TRUE
The counter value is written to index 0x60n2:12 "Latch value 2" at every parameterized edge at the Gate/Latch input.
There is no need to reactivate index 0x70n0:0C or 0x70n0:0D. - The status of the Gate/Latch input can be recorded via index 0x60n0:0C "Status of input gate".
- Saving of the counter value in index 0x60n0:22 "Latch value 2" is confirmed via bit 0x60n2:12 "Latch extern 2 valid".
| Simultaneous use of Gate und Latch extern 2 When using index 0x80n0:04 "Gate polarity" (1 = "Enable pos. gate") and simultaneously activating index 0x70n0:0C "Enable latch extern 2 on positive edge", the current counter value is initially stored in index 0x60n0:22 "Latch value 2" when a positive edge is detected at the Gate/Latch input. The counter value is then blocked. The same applies to the use of index 0x80n0:04 "Gate polarity" (2 = "Enable neg. gate") and simultaneous activation of index 0x70n0:0D "Enable latch extern 2 on negative edge" at a negative edge at the Gate/Latch input. |
| Multiple activation of the latch function If several commands are activated simultaneously to save the counter value in the "Latch value" process data (index 0x60n0:12), only the command that is set first is accepted by the terminal.
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