Created Date: November 27,2012

Created by: Steve Bailey

On a Modbus network only the master can initiate communications, so when the HMI is the master and the drive and PLC are slaves, the PLC can't initiate communications. However, the PLC could set a bit that the HMI could monitor and send on to the drive.

HMIs are almost always masters. Generally they don't give you a choice about whether they are a master or a slave.

Created Date: November 27,2012

Created by: franji1

Modbus/TCP supports multiple masters. Is it possible to run Ethernet cable vs. twisted pair?

You can still have Modbus/RTU slave devices like drives by utilizing a Modbus Gateway, which takes Modbus/TCP Master requests via Ethernet on one side, and translates that (via the Unit ID) to (possible multiple) Modbus/RTU slaves on the 485 side.

HMI: Modbus/TCP Master to PLC as Modbus/TCP Slave

PLC: Modbus/TCP Master to either/or Modbus/TCP Slaves (drives, etc.) or Modbus Gateways to Modbus/RTU Slaves (drives, etc.)

Modbus/TCP uses the IP Address as the "primary node " address, but then you can utilize the BYTE sized Unit ID to address RTU devices via a Modbus Gateway device.

Created Date: November 27,2012

Created by: kewakl

Does their software have a Click-compatible driver?

Does their software have drivers for all the other desired devices?

If, so...

You can use the protocol converter feature.

Select both protocols, define your data transfer block, select the other device's data and it is almost magic.

Check your product tech guy, they may have a cable that works. I think that their cable for the DL (Koyo model 2) may work for the Click.

The G3 does have a feature that is way better than the similar feature of AD's C-More offerings.

The G3's blow-mold packaging is a better development enclosure than the AD cardboard packaging .:rolleyes::D

Created Date: December 01,2012

Created by: JustBlaze

Red Lion doesn't have a driver for the click yet. If I was to stick with modbus rtu for our silo unloader that I set up a few months ago how would I handle that?

It has a click plc, two ac tech mc series vfd's and will have the red lion g3 kadet hmi. Right now the drives are being started and stopped with 10v looped from the vfd to the plc contact and back.

Thanks

-Justin

Created Date: November 27,2012

Created by: JustBlaze

Hi Guys,

I have a question regarding the scheme of having a hmi panel, plc and vfd's all on the same modbus rtu network. Would the hmi be the master?

If the HMI was the master and the drives and plc were slaves then could the plc still initiate communication to the drives?

In the future at our plant we would like to automate our dust collection system. The system consists of blowers, linear actuators, silo loader, etc...

We extensively have used AC Tech MC series drives which include modbus communication via RS48.5. I'm wondering though if someone was to setup a plc with this system how they would do it.

The system would have a HMI panel, digital inputs and outputs for the linear actuators and regular motor starters. Then modbus to the drives? Would there be a better way? I know modbus rtu has it's limitations on amount of peers.

Finally has anyone connected a Red Lion G3 HMI to a click plc? That's my current project, The communications port on the hmi is a female DB9 so I grabbed a coupler and was going to use a CLICK programming cable to port 2 on the plc with RS232 on the hmi doing modbus. I have read on a forum though that the click programming cable has certain pins internaly jumpered and this will not work. So I guess I would have to make up my own cable then?

Thanks in advance

any and all advice and info is greatly appreciated!

-Justin