Siemens SED2-MODBUS2 Technical Instructions
Technical Instructions
Modbus RTU Interface Module for SED2
Document No. 155-767
February 25, 2009
Description
Product Part Number
Contents
Required Tools
The Modbus RTU Interface Module for SED2 enables serial communication
between a Modbus RTU and a SED2 Variable Frequency Drive (VFD).
SED2-MODBUS2
• MicroGate II Interface module.
• Local cable for USS communication with SED2.
• Network cable for ModBus communication with Building Automation
controller.
• Installation documentation.
Personal computer for configuring device prior to operation.
Configuration Kit (SED2-MODBUS2_KIT), containing:
• External Power Supply for the MicroGate II.
• 9-pin (female) to 9-pin (female) Serial Null Modem Cable.
• Installation documentation.
NOTE: Both the Interface Module and the SED2 must be configured prior to
operation.
Figure 1.
Siemens Industry, Inc.
Technical Instructions Modbus RTU Interface Module for SED2
Equipment damage, or loss of data may occur if
WARNING:
Document Number 155-767
February 25, 2009
Warning/Caution Notations
WARNING:
Personal injury/loss of life may occur if you do not
perform a procedure as specified.
Hardware Setup
Power Supply
Programming Switch
CAUTION:
you do not follow procedure as specified
Power may be supplied by either connecting the configuration kit power supply to one side of
the unit, or by providing regulated 6 to 28 Vdc power to pin 9 of the local serial port from the
SED2. See Figure 2.
Do not connect the external 9 Vdc power supply and pin 9
of the LOCAL cable at the same time.
The Programming (PRG) Switch on the Interface Module, should always be in the RUN
position (up) for normal operations and configuration.
The PRG position is used strictly for loading firmware at the factory.
The Interface Module comes with two serial ports. See Figure 2.
The LOCAL port is for connection to a SED2 and supports both RS232 and RS485 (2-wire
and ground) communications. The LOCAL port is also used for configuration and
programming of the Interface Module.
The NETWORK port is for connection to a network and supports RS485 (2-wire)
communications.
Figure 2. Interface Module Hardware.
Page 2 Siemens Industry, Inc.
Modbus RTU Interface Module for SED2 Technical Instructions
A four wire cable (Figure 5) connects the LOCAL port on the Interface Module to an
Document Number 155-767
February 25, 2009
Hardware Setup, Continued
The Interface Module is provided with two cables.
A three wire cable (Figure 3) connects the NETWORK port to a network. Because the
network connection type may vary among different installations, the cable ends are
stripped wires to provide maximum flexibility.
Figure 3. Three Wire
Network Cable.
Figure 4. RS485 Network Cable.
SED2. The cable ends in stripped wires to facilitate a connection to the SED2 drive
terminals shown below.
CAUTION:
SED2 drive power should be off while connecting
the wires to the drive terminals.
Figure 5. Four Wire
Local Port Cable.
Figure 6. SED2 Drive Cable.
Figure 7. Cables Installed on Interface Module.
Siemens Industry, Inc. Page 3
Technical Instructions Modbus RTU Interface Module for SED2
Document Number 155-767
February 25, 2009
Hardware Setup,
Continued
LED Indicators
There are a total of three bi-color LED indicators on the Interface Module. See
Figure 8. The NET LED displays communications activity on the Network (Modbus)
port.
• The STAT LED displays the overall status of the Interface Module.
• The LCL LED displays communications activity on the Local (SED2) port.
During normal operations, the NET and LCL LEDs will quickly alternate red and green
flashes, making it look almost amber; this is normal.
Table 1. Interface Module General Status LED (Stat).
For this state: LED is: To indicate:
No power Off No power applied to the device.
Run Mode
Configuration Mode
Fatal Error
Flashing Green
(250 ms On, 250 ms Off)
Flashing Green
(1.5 sec on, 1.5 sec Off)
Flashing Yellow
(250 ms On, 250 ms Off)
Interface Module is operating
normally in RUN Mode.
Interface Module is in
CONFIGURATION Mode.
Interface Module has
experienced a fatal error, and
has halted communication.
Figure 8.
NOTE: If the Interface Module has been installed correctly, the STAT LED will be
flashing green, and the LCL LED will be alternating so fast between red and
green that it will appear to be glowing amber.
Table 2. Network Communication Activity LED (NET).
For this state: LED is: To indicate:
Received Data Red Data from the Modbus Network.
Transmit Data Green Data onto the Modbus Network.
Table 3. SED2 Communications Activity LED (LCL).
For this state: LED is: To indicate:
Received Data Red Data from the SED2.
Transmit Data Green Data to the SED2.
Page 4 Siemens Industry, Inc.
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