Chapter 4 - 7SR45 Data Communications Definitions
© 2018 Siemens Protection Devices Limited
Chapter 4 Page 11 of 20
4.4
Measurands
The following measurands EVT and INF numbers apply to this device.
FUN
INF
Description
ASDU
COT
183
148
Measurand IL1,2,3
---
IL1 (2.4x)
IL2 (2.4x)
IL3 (2.4x)
9
Cyclic -
Refresh
rate 5 s
NOTE:
In the IEC103, message frames are separated by a silent interval of at least 3.5 character times. This
time interval is also called t3.5. This t3.5 delay needs to be provided by the IEC103 master for
response to another query.
7SR45 Argus Relay follows the below equation for satisfying the silent interval time.
tdelay required = 11 x 3.5/b
Where,
11 = bits
b = baud rate in bps
tdelay for 7SR45 = tdelay re 10 ms tolerance
Data transmission
tp
tv
rdis
tn
ts
TXD
RTS
tp …… Pause time (pause before “RTS = ON”)
tv …… Setup time (transmission delay after “RTS = ON”)
tn …… Hold Time (pause time after sending before “RTS = “tOFF”)
ts …… Hold receiver disabled after “RTS = OFF”
rdis …… Disable receiver when using half duplex protocol
Note: Only active when “ts = 0”
Figure 2-3
Time Settings for Message Frame
tp or ts must be equal to
tdelay for 7SR45
.