Modbus Slave Devices; Function Description; Configuration And Evaluation Via User Interface - Siemens SICAM Q100 7KG95 Series Manual

Parameter
Data type
Bad meg.
Commissioning
If a Modbus slave device is connected correctly, the serial parameters (baud rate and parity) are identical to
the parameterization in the Modbus RTU master of the device, the device address was checked, and the errors
no responses or CRC errors still occur (sporadically), proceed as follows:
•
Try to increase the Response timeouts. Some devices may take longer to respond (in particular when
reading a larger number of values with 1 message) or at low baud rates.
•
Try to increase the Additional inter-character timeout. There may be larger message gaps during the
transmission or a device needs a longer bus silent interval.
2.8.3

Modbus Slave Devices

2.8.3.1

Function Description

For the correct functioning of the Modbus RTU Master, the Modbus RTU Master must know all Modbus slave
devices which are connected to the RS485 interface. Also the data which the devices must read must have
been defined.
NOTE
i
i
Modbus slave devices can only be parameterized if you select the communication protocol Modbus
RTU Master.
You can parameterize up to 8 Modbus slave devices. They can be selected in the 2 groups Modbus slave
devices 1-4 and Modbus slave devices 5-8.
The parameterization of the 8 Modbus slave devices is identical and described only for the Modbus slave
device 1 in the following.
NOTE
i
i
The parameterization sequences for the Modbus RTU Master and the Modbus Gateway are described in
detail in chapter
2.8.3.2

Configuration and Evaluation via User Interface

Basic Settings
To change the basic settings for Modbus slave devices in the Configure tab, proceed as follows:
•
In the navigation window, select Administrative and click Modbus slave devices 1-4.
SICAM, SICAM Q100 7KG95xx, Manual
E50417-H1040-C522-A8, Edition 09.2020
2.9 Modbus TCP to Modbus RTU
Description
Data type requested with this request message (one
or more data objects of this data type were
requested; different data types are always requested
with separate messages, because they have different
scan cycles).
Counter for errors of this request:
•
No responses
•
Exception responses
•
CRC errors
Gateway.
Device Functions
2.8 Serial Communication
175