PowerFlex 4 40 with micrologix1100 on ModbusRTU broadcast

PowerFlex 4 40 with MicroLogix1100 on ModbusRTU broadcast Distribution Related to Open Inverter Use Rockwell Offices Options Use Drives Team Application Experience (Name) only Page 1 of 6 Generated by.

Overall Description

PowerFlex 4 class drives can be controlled over Modbus RTU using the built-in serial interface (DSI connector) on the drive This application note details the Micrologix 1100 plc being used as Modbus RTU master to control PowerFlex 4 class drives using broadcast control

To control a drive on Modbus RTU, each drive needs to use a seperate message (MSG) command for the Logic Control word, Speed Reference word, Logic Status word and Speed Feedback word With a large number of drives on the network, it can take a significant period of time before the MSG instruction for the last drive to start, is executed Modbus RTU supports a global broadcast feature, whereby one MSG instruction is used to write the same value to same register in every drive, by using the Modbus RTU command ‘16’ to the Modbus address ‘0’ This means that we could broadcast the Logic Command word to start /stop all the drives together, or provide a common speed reference to the drives This could significantly reduce the time to control a number of drives on the network

The MicroLogix 1100 has an embedded multi functional LCD for on-line editing, and EtherNet/IP for connecting to an peer to peer network or our programming PC The 2 PowerFlex drives being used in this test are a PowerFlex4 setup as Node 1, and a PowerFlex4M setup as Node 2

Equipment used for test

MicroLogix 1100 1763-L16AWA

RSLogix500 CPR ver 7 and RSLinx ver 2.51

The PowerFlex 4 class drives need a minimum firmware revison to support Modbus RTU code ‘16’: PowerFlex 4 – frn 4.02

PowerFlex4M – frn 1.01

PowerFlex40 – frn 3.03

PowerFlex40P and 400 have not been tested

1761-CBL-PM02 ser B, PC to MicroLogix programming cable

1763-NC01 The phoenix plug pin connectons are the same as the RS485 on the NET-AIC

AK-U0-RJ45-TB2P 2 position terminal block

Modbus RTU requires a 120 Ohm terminator at each end of the network Putting a link between pins 1

& 2 of the terminal block terminates one end, and a 120 Ohm resistor is screwed into the 2 position terminal block at the other end

Drive Parameter setup

Drive parameters need to be setup as below When para change complete, cycle the drive power Parameter PF4,

40, 40P, 400

MicroLogix Setup

The MicroLogix 1100 needs to be setup first using the serial cable 1761-CBL-PM02 on channel 0

If when connecting to the ML1100 an error is reported that it is not an SLC, then upgrade RSLogix to ver

7 and RSLinx to ver 2.50

Startup RSLogix500 and create a new project with the Micrologix 1100

Select channel configuration

Setup Channel 1 EtherNet IP address and subnet Make sure you uncheck the BootP enable, and then download to the controller To make the IP address stick, cycle the power on the ML1100

Now we have the IP address in the ML1100, then we can reconfigure our computer and go-line using the EtherNet connection This will allow us to remove the serial cable 1761-CBL-PM02 on channel 0, and use plug in the 1763-NC01 and reconfigure Channel 0 for Modbus RTU

Additionally ensure that the settings within the ML1100 are setup on the LCD:

ESC … Scroll down … Advance Set …… DCOMM Cfg = disable

Change to cable 1763-NC01, and select the channel configuration as before

Setup channel 0 to be Modbus RTU master at 19200 with no parity

Make sure you adjust the protocol control from the default No handshaking to No handshaking (485 network) and the timeouts /delays to 20ms

Download configuration to controller using the EtherNet connection

Once the ML1100 is in run mode, both COMM0 and COMM1 will be flashing fast

The ML1100 communicates with the drive using MSG instructions on Modbus RTU So we create a number of MSG instructions for the Logic control, reference , logic status and drive speed feedback

The MSG instructions are cascaded so that they all operate in sequence This scheduling of MSG instructions is necessary to ensure that each instruction receives its hand-shake and completes properly

The logic command data will be stored in N15:0, so configure the message to send N15:0 to the Modbus address for the logic command at 8192 (this means modbus sends to address 8193) Notice that we use the command ’16 Write Multiple Registers’, and the Slave node address is ‘0’

When the program is downloaded, we can go online and change the logic word to start and stop the drive Double click on the N15 data file, and change the value of N15:0 to 2 The drives will now start

Changing the value of N15:0 to 1 will stop the drives

The bits that are part of the Logic Control word are:

The plc MSG 11:1 broadcasts the reference to all drives on address 8194 via N15:1 Therefore change the value of N15:1 between 0 to 500 = 50.0Hz

The broadcast message is a write MSG to all the drives on the network, typically used for the Logic Control and reference words Other drive registers would be read with a single MSG ’03 Read Holding Register’ command The most important registers are:

Remember to add 1 to the address when used in the MSG setup screen

The program associated with this test is called

MODBUS_RTU_WITH_MICROLOGIX_1100_AND_POWERFLEX_4_DRIVES_BROADCAST.RSS