Profibus Termination; Profibus Dp-Parameterization - GE MM300 Manual
Motor management system/low voltage motor protection and control
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Also See for MM300:
- Instruction manual (198 pages) ,
- Quick start manual (77 pages) ,
- Installation recommendations (21 pages)
Table of Contents
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CHAPTER 4: FIELDBUS INTERFACE
NOTE:
NOTE
Profibus termination
Profibus DP-parameterization
MM300 MOTOR MANAGEMENT SYSTEM – COMMUNICATIONS GUIDE
Figure 4-1: Comms board power supply configuration
ON
1 2 3 4 5 6 7 8
ON
1 2 3 4 5 6 7 8
= switch position
Protocol Options
SW1
DeviceNet
ON
Profibus
OFF
Supply Options
SW5
Internal Supply
ON
External Supply
OFF
Other switch combinations are not allowed.
Profibus segments should be terminated by a bus termination. The MM300 termination
voltage is +5V and the connections are as follows:
Figure 4-2: Profibus termination
+5V
Line B
Line A
Data ground
If the bus voltage level is higher, such as 24V, an external device must be used to drop the
voltage to the required +5V termination level. The Procentec T1 Terminator or equivalent is
suitable to provide proper termination to the MM300 from a 24V level.
The MM300 relay supports mandatory parametrization. The relay keeps its user parameter
data / setpoints in a non-volatile memory and does not need device related
parametrization during startup of the DP master. The EnerVista MM300 Setup software is
the best tool for user parametrization of the MM300 device.
PROFIBUS WITH INTERNAL SUPPLY
PROFIBUS WITH EXTERNAL SUPPLY
853845A1.CDR
SW2
SW3
ON
OFF
OFF
ON
SW6
SW7
ON
OFF
OFF
ON
853847A1.CDR
PROFIBUS DP
SW4
OFF
ON
SW8
OFF
ON
Ω
390
Ω
220
Ω
390
4–5
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Questions and answers
we have a problem with device MM300. it says that the device is invalid through the software and does not read the device. the communication is through RS 485. is it possible to give us an advice or send us some reccomendations or instructions?
For a GE MM300 device that is not recognized by software and communicates via RS485, follow these troubleshooting steps:
1. Ensure correct RS485 wiring:
- Use two-wire RS485 in a daisy chain configuration.
- Install a 120 Ohm resistor in series with a 1 nF ceramic capacitor at each end of the link.
- Use shielded wire and ground the shield at only one location.
2. Check device addressing and termination:
- Confirm proper device address and ensure no address conflicts.
- Verify that termination networks are correctly installed at both ends.
3. Confirm half-duplex communication:
- Ensure that the system supports half-duplex communication and not sending and receiving data simultaneously.
4. If using USB for setup (e.g., USB-to-RS485 converter) and the device is not recognized:
- Repeat the connection procedure 2–3 times.
- If still not recognized, uninstall the USB driver from Device Manager under modems.
- Disconnect the USB cable, wait at least 10 seconds, then reconnect.
- When prompted by the Hardware Wizard, select "No, not this time," then "Install the software automatically," and press "Continue Anyway."
- Finish the installation and check if the USB device appears in the setup software.
These steps help ensure proper hardware connection and correct software recognition of the MM300 device.
This answer is automatically generated