ProSoft Technology MVI94-MCM-MHI - Manual (Page 63)

MVI94-MCM ♦ Flex I/O Platform Diagnostics and Troubleshooting
Serial Communications Modbus Communication Module User Manual
ProSoft Technology, Inc. Page 63 of 109
March 29, 2011
4.5 LED Definition
This section defines the indications provided on the MVI94-MCM module through
LEDs. A description of each LED is provided in the following topics.
4.5.1 PRT1
This LED indicates data transmit and receive activity on the configuration port.
When the TXD or RXD pin is active on the port, the LED will illuminate green.
When the port is not active, the LED remains in the off state.
4.5.2 U1
This LED indicates backplane data transfer operation. When the module is
successfully writing data to the FLEX I/O backplane, the LED will be in the off
state. When the module is reading a new block of data from the FLEX I/O
backplane, the LED will be in the on state (amber). During normal operation of
the module, this LED should turn on and off at a vary rapid rate. If the LED never
turns on, check your ladder logic to verify that the data transfer is set up
correctly.
4.5.3 U2
This LED indicates communication errors on the Modbus master port. The LED is
illuminated (amber) when no error exists on the port. If a communication error is
recognized on the port, the LED will turn off. If the LED is off, check for errors in
the command list to determine the error condition recognized by the module.
4.5.4 STS
This LED indicates the "health" of the module. When power is applied to the
module, the LED is illuminated. If the LED is green, the program is working
correctly and the user configuration is being used. If the LED is red, the program
is halted. Try restarting the module by cycling power.
4.5.5 PRT2
This LED indicates data transmit and receive activity on the Modbus master port.
When the TXD or RXD pin is active on the port, the LED will be green. When the
port is not active, the LED will be off.