Siemens 7KM1020-0BA01-1DA0, Manual, Page: 20 / 94

Description
2.5 RS485 interface
PAC1020
18
Equipment Manual, 05/2020, L1V30610008B-01
Pulse length, turn-off time
① Pulse length
② Turn-off time
Figure 2-5 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.
2.5 RS485 interface
RS485 interface for Modbus RTU communication
The PAC1020 is equipped with an RS485 interface for Modbus RTU communication. The
device operates as a Modbus slave.
Application
This interface permits:
•
Reading out the measured values
• Reading and writing the device settings
• Use of the SENTRON powerconfig commissioning/parameterization software
• Updating the device firmware
The Modbus function codes are listed in the Appendix.
Conditions for operation
To use the interface, the device must be parameterized in accordance with the existing
Modbus infrastructure. The communication parameters can be set on the device and via the
Modbus RTU interface.