Chapter 4 - 7SR45 Data Communications Definitions
© 2018 Siemens Protection Devices Limited
Chapter 4 Page 18 of 20
5.2.9.4
Holding Registers (Read Write Registers)
Address
Name
Format
Multiplier
Description
40001
Time
TIME_METER
0.000000
Time
NOTE:
In the RTU mode, 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 Modbus RTU 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 2-4
Time Settings for Message Frame
tp or ts must be equal to
tdelay for 7SR45
.