Siemens SENTRON PAC3100, Manual, Page: 26 / 152

Description
3.6 RS 485 interface
SENTRON PAC3100
26
Manual, 07/2009, A5E02385159B-01
Remote control via the RS 485 interface
The integral RS 485 interface enables remote control of the digital outputs. The Modbus
function codes are listed in the Appendix.
Wiring
Both digital outputs are passive and implemented exclusively as switches.
Implementation of the pulse function corresponds to the IEC 62053-31 standard.
Pulse length, turn-off time
(1) Pulse length
(2) Turn-off time
Figure 3-9 Pulse length and turn-off time
● Pulse length:
Time for which the signal at the digital output is "high". The minimum pulse length is
30 ms and the maximum 500 ms.
● Turn-off time:
Time for which the signal at the digital output is "low". The turn-off time depends on the
measured energy, for example, and can be days or months.
● Minimum turn-off time:
The minimum turn-off time corresponds to the programmed pulse length. 30 ms is the
absolute minimum.
See also
Modbus RTU (Page 125)
3.6 RS 485 interface
RS 485 interface for Modbus RTU communication
The SENTRON PAC3100 is equipped with an RS 485 interface for Modbus RTU
communication.
Application
This interface permits:
●
Reading out the measured values
● Reading and writing the device settings