CompactLogix + 1761-NET-AIC to HMI via DH485 communication

mahone

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Join Date
Apr 2014
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Singapore
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Hi guys!

In my current project. I'm using a CompactLogix 1769-L32E and an HMI panel called Etop507. Due to distance requirements i have to use DH485 between CompactLogix PLC and the HMI panel.

The HMI panel has a RS232, 2 USB and 2 Ethernet port.
I have connected the Channel 0 of the PLC to RS232(port 2) of a 1761-NET-AIC+ and i use port 3(the DH485 port) of the 1761-net-aic to connect to the RS232 of the HMI panel.

I have configured the HMI panel to DH485 and the PLCs Channel 0 to DH485.

The HMI panel software JMobile suite supports DH485 and tags can be defined using SLC500 type addresses. I used the "SLC500 data mapping" facility under logic in RSLogix5000 to map a simple INT array.

I wrote few test MSG instruction in RSLogix5000 to send a data block using CIP data table write...but when it comes to "node id" i can't figure it out

I appreciate if anyone can help

Thanks
 
thanks for the reply..

i tried to read the first element of the INT array that i mapped in RSLogix5000
into a tag but it failed...HMI reports an error MSG "READ BLOCK FAILED"

then i tried ModbusRTU protocol and the sample program from AB site with the same setup i can communicate with the HMI..

DH485 protocol

Controller Config >> user, 9600,8,none1,no handshaking & DH485, station address = 5
HMI protocol config >> salve id = 5

ModbusRTU protocol

same controller configurtion
HMI protocol config >> Node id=5 and i use 5 for the slave id in the logic a well...
 
In RSLogix 5000 on the Serial Port tab, set the Mode = System.

DF1 and DH485 are "system" mode drivers for the ControlLogix/CompactLogix. "User" mode is for ASCII and other binary protocols that rely on the user program rather than on built-in communication functions of the controller operating system.
 
Project was put off some time and has resumed.

As you said when i changed to System i can establish a communication now.
But the requirements has increased. Now i have to connect one more HMI to the same network.

I tried a daisy chain. Took the A and B terminals of the 1747-NET-AIC and connected to the first HMI and then from that two ends took a pair of wires to the second HMI. I can see the data changing but data is not stable.

I terminated the wires according to the HMI panel data sheets.
It says short 3&4 of the RS232 of the HMI and connect to A, short 7&8 of the RS232 of the HMI and connect to B, and connect the GND to pin 1 of RS232 of the HMI.

In this way i can make clear communication only if one HMI is connected but when the second one is connected data is unstable.

Do i need to add resistors to end terminals If so how should i terminate them?

Thanks
 
Are your HMI devices RS-232 or RS-485 ? They really need to be RS-485 if they are going to work with this wiring.

RS-485 needs THREE wires, not just two. A-B provides the common reference as the "COM" wire.

It sounds like your HMIs provide a "GND" pin as a reference, so run a conductor from the "COM" terminal on the 1761-NET-AIC to that pin on each HMI.

Using ground as the common reference is not ideal, but it often works.

Rockwell never licensed DH485 protocol to any competitors, so it's also possible that your HMI devices just won't work correctly with multiple HMI peers on the network because they weren't designed or tested to do so.
 
MY HMIs are two Uniop Etop507 from Exor International.

They have one RS232 port for PLC communication which i'm using. The HMIs can be configured as RS232 and RS485 using JMobile Suite the software provided for developing HMI programs for these panels.

The software has many Tag protocols among which i tried DF1, DH485, Modbus RTU, Modbus RTU Server.

Yes. Cable wiring shown in the datasheets connects the COM of the DH485 port of the 1747-NET-AIC to the pin of the RS232 port of the HMI for DH485 configuration. I also tried connecting each HMIs GND or pin 1 of the RS232 to the COM of the DH485.
Nothing much changed.

I'm thinking of testing with two panel view plus with the same wiring configuration. Would that be a good idea?
 
I'm confused by your statements about whether the physical ports on the ETOP507 are RS-232 or RS-485.

Can you point to a wiring diagram or user manual that clearly shows and describes the port you are using ?
 
Ken,

The serial port is configured in software, as mahone last said. It can be RS-232, RS-485, or RS-422 and also by looping the pins for DH-485 as mahone outlined in an earlier post. Here's the manual...

UniOP eTOP Series 500 Operating Instructions

mahone,

I'm just wondering, do you have unique node addresses for both HMI?

Regards,
George

etop507.jpg
 
Jack

The second HMI is installed far from the main panel. Due to the long distance we can't use Ethernet for remote panel. I'm not sure if i can use Ethernet for Local HMI and DH485 for remote HMI.
 

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