Timestamp function
The timestamp is made possible by the distributed clocks technology in the EtherCAT system. This local clock can be used to synchronize the data acquisition.
The EL5112 provides a timestamp for the following input signals:
- last counter change in the PLC cycle
- Zero pulse C input: when storing the counter value on the positive edge of the zero pulse C
- Latch input: when storing the counter value on the selected edge of the Latch input
- Gate/Latch input: when storing the counter value on the selected edge of the Gate/Latch input
 | Note on using the timestamp function In order to be able to use the timestamp function, the terminal must be operated in "DC Synchronous" or "DC Synchronous (input based)" mode. |
The terminal provides the timestamp in a range of 64 bits, optionally with only 32 bits. The timestamps are contained in the following "Predefined PDO Assignment":
Predefined PDO Assignment |
|---|
1.Ch Standard, 1xABC, extended DC mode, 64 Bit time stamp |
1.Ch Standard, 1xABC, extended DC mode, 32 Bit time stamp |
They can be selected or deselected as optional PDOs.
PDO Assignment | Name | Description |
|---|---|---|
ENC Timestamp Channel 1 | Contains timestamps in the 64 bit range for channel 1 | |
ENC Timestamp Compact Channel 1 | Contains timestamps in the 32 bit range for channel 1 |
Timestamp for the last counter change in the PLC cycle
The process data index 0x60n0:16 "Timestamp" indicates the timestamp of the last registered counting pulse in the PLC cycle. This means, depending on the counter evaluation mode (index 0x80n0:06 "Evaluation mode") the timestamp is output based on:
0x80n0:06 "Evaluation mode" | 0x60n0:16 "Timestamp" | |
|---|---|---|
0 | 4-fold (default) | last rising or falling edge on track A or B |
1 | 1-fold | last rising edge on track A |
2 | 2-fold | last rising or falling edge on track A |
Timestamp on input zero pulse C
The process data index 0x60p0:1F "Timestamp C" outputs the timestamp of the last registered positive edge of the zero pulse C when the counter value is saved.
Parameterization of the zero pulse C input | 0x60p0:1F: "Timestamp C" issues the timestamp based on: | |
|---|---|---|
0x70p0:01 | Enable Latch C | the positive edge of the zero pulse C at which the counter value was stored in index 0x60p0:12 "Latch value" |
Depending on the number of channels applies: p = 0 for Ch1, p = 1 for Ch2 | ||
Timestamp for the Latch extern input
The process data index 0x60p0:20 "Timestamp latch" indicates the timestamp on the selected edge of the Latch extern input. This means that, depending on the parameterization of the Latch extern input, the timestamp is valid for:
Parameterization of the Latch input | 0x60p0:20 "Timestamp latch" issues the timestamp based on: | |
|---|---|---|
Enable latch extern on positive edge | the last rising edge at the Latch extern input at which the counter value was stored in index 0x60p0:12 "Latch value" | |
Enable Latch extern on negative edge | the last falling edge at the Latch extern input at which the counter value was stored in index 0x60p0:12 "Latch value" | |
Depending on the number of channels applies: p = 0 for Ch1, p = 1 for Ch2 | ||
Timestamp for Gate/Latch input
The process data 0x60p0:21 "Timestamp latch 2" indicates the timestamp on the selected edge of the Gate/Latch input. The Gate/Latch input can also be used as Latch extern 2 input. Depending on the parameterization of the Latch extern 2 input the timestamp is valid for:
Parameterization of the Latch 2 input | 0x60p0:21 "Timestamp latch 2" issues the timestamp based on: | |
|---|---|---|
Enable Latch extern 2 on positive edge | the last rising edge at the Gate/Latch input at which the counter value was stored in index 0x60p0:22 "Latch value 2" | |
Enable Latch extern 2 on negative edge | the last falling edge at the Gate/Latch input at which the counter value was stored in index 0x60p0:22 "Latch value 2" | |
Depending on the number of channels applies: p = 0 for Ch1, p = 1 for Ch2 | ||