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Products: MP-C
Functionalities: Hardware
Product version: 2023, 2024

MP-C Controller LEDs

arrow1_rotationStatus LED arrow1_rotationRS-485 LEDs arrow1_rotationEthernet LEDs

There are five or three LEDs on the front panel of the MP-C controller, depending on the MP-C model.


MP-C controller models with “-M” in the product name do not have Ethernet ports with associated LEDs. These MP-C models only have three LEDs: Status, RS-485 Tx, and RS-485 Rx. For more information, see MP-C Models .

action_zoom_plus_stroke MP-C controller LEDs

MP-C controller LEDs

Table: MP-C Controller LEDs



Status (MP-C controller)


RS-485 Tx


RS-485 Rx


Ethernet 1


Ethernet 2



The MP-C controller Ethernet and Status indicators comprise two LEDs (green/yellow and green/red respectively) in one structure.

The LEDs indicate status of the MP-C controller and the ongoing communication.

Status LED

The MP-C controller Status LED indicates the condition of the device.

Table: MP-C Controller Status LED Patterns

LED Patterns


Green, constant

Normal operation, status OK

MP-C controller firmware application running

Green, flashing (~1 Hz)

Device restarting, wait

MP-C controller firmware application running

Red, constant

Detected error, attention required

Red, flashing (~1 Hz)

Device operates, but a problem needs attention

Red/green, flashing (~1 Hz)

MP-C controller I/O board receiving software upgrade, wait

Do not interrupt power to the controller. For more information, see the following Important note.

Amber, constant

MP-C controller firmware boot applet running

Amber, flash

Device restarting, wait

MP-C controller firmware boot applet started

Amber/green, flashing (~1 Hz)

MP-C controller firmware is being upgraded. It is typically the firmware main application, but it can also be a boot applet.


Avoid power interruptions to the device during the brief period when the Status LED is flashing red and green. An interruption causes problems with the I/O processor upgrade and can result in corrupt firmware. You can view the evidence of a corrupt processor when the device reports itself as an “MP-C-15A.” A corrupt I/O processor can lead to the loss of the reset button and/or I/O functionality, as well as the inability to upgrade the I/O processor and/or the device.

RS-485 LEDs

The RS-485 LEDs indicate the condition of the RS-485 network data communication.


The labeling of the RS-485 LEDs differs between different versions of the MP-C controller models. In previous versions, the LEDs are labeled “Sensor Bus”.

Table: RS-485 LED Patterns

LED Patterns


Yellow, flashing (Tx)

Transmit data

Green, flashing (Rx)

Receive data

Ethernet LEDs

The Ethernet (1 and 2) LEDs indicate the condition of the Ethernet communication.

Table: Ethernet LED Patterns

LED Patterns


Green, flashing

10 Mbit communication

Yellow, flashing

100 Mbit communication

Green/yellow, constant

10/100 Mbit link connected, no activity

No light

No link, no activity

  • MP-C Controllers
  • MP-C Models
  • Status LEDs