Profibus Dp - 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
Profibus DP
MM300 MOTOR MANAGEMENT SYSTEM – COMMUNICATIONS GUIDE
To enable the Profibus physical interface, ensure that switches 3 and 4 of the DIP switch on
the communications card (on the CPU module) are ON, and that switches 1 and 2 are OFF.
The external connections through the Fieldbus interface are as follows:
Table 4-1: Fieldbus interface external connections (Profibus)
Pin
V–
L
C
H
V+
Table 4-2: DB9 signal pin applicability to MM300
DB9 pin (external device)
1
2
3
4
5
6
Connection (external device)
Pin 5
Pin 8, line A (negative TX/RX)
Common drain
Pin 3, line B (positive TX/RX)
Pin 6
MM300 pin
Signal
C
(shield)
No connection
M24
H
RxD/TxD-P
No connection
CNTR-P
V-
DGND
V+
VP
PROFIBUS DP
Description
Shield or potential equalization
Ground of 24V power supply
Receive/Transmit data; line B (red)
Repeater control
Data ground (reference voltage to VP)
Power supply*
1
4–3
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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