Baumer ATD - Manual (Page 28)

EtherCAT 28/42 Baumer Thalheim GmbH & Co. KG
2011-10-04/rnik Eschwege, Germany
6 DC Timing
The exact data sampling time while DC mode depends on the sum of the two parameters: 0x1C33:3 (= Shift
Time) and Tjs (Jitter on sampling time). The minimum cycle time depends on the setting of the Scaling Func-
tion Control bit.
The time the encoder needs (from the SYNC0 signal point) to be able to put process data into the DPRAM
can be estimated by adding the Shift Time and the Calc and Copy Time (Table 31 Calc and Copy Time).
6.1 Consecutive sample point jitter
For the system designer there one value of interest: the absolute jitter between two consecutive sampling
points (Jitter) J. This value includes all device systematic jitter sources. Please refer to Table 32.
6.2 Shift Time
Shift time is defined to be the time the encoder needs to start sampling data. This time information plus the
absolute system time gives the time stamp of the actual sample value. This means the sampled position data
has a fix relationship to the DC clock of the network.
6.3 Calc and Copy Time
The time the slave controller need for calculate and copy the sampled data to the SM data buffer (e.g. into
Ethernet Frame) strongly depends on the SFC bit.
Calc and Copy Time [µs]
Device Name
Product
Code Device
Type
SFC=0 SFC=1
9
SFC=1
10
ATD4 B ***Y*** 15/16EC 0x0001**** 0x0002 **** 26,4 29,8 41,0
ATD4 B ***Y*** 17/12EC 0x0001**** 0x0002 **** 41,8 41,9 42,0
ATD4 B ***Y*** 15EC 0x0001**** 0x0001 **** 23,5 23,9 28,1
ATD4 B ***Y*** 17EC 0x0001**** 0x0001 **** 33,7 33,8 36,8
ATD2 B ***Y*** 14/16EC 0x0002**** 0x0002 **** 28,6 30,8 40,4
ATD2 B ***Y*** 17/12EC 0x0002**** 0x0002 **** 42,8 42,9 43,0
ATD2 B ***Y*** 14EC 0x0002**** 0x0001 **** 23,5 23,9 28,1
ATD2 B ***Y*** 17EC 0x0002**** 0x0001 **** 34,7 34,8 37,8
Table 31 Calc and Copy Time
For a full information about relationship between shift time, calc and copy time, Ethernet Frame length and
SYNC0 generation please refer to LIT[05].
9
Value is given for Scaling Function Control enabled and default encoder resolution
10
Value is given for Scaling Function Control enabled and lowest encoder specific resolution value.