Remote I/O rack & control panel with HC900

[fdomin]

I would like to understand required connection of a remote rack and a remote compressor control panels to a HC900 controller.
The rack and the control panel are for new equipment to be installed and the HC900 is existing.
Signal from the remote rack goes to a remote ethernet switch, then to a remote Fiber optic converter for a 1500 meter fiber optic run. In the control room another FO/ethernet converter and switch connects to the HC900.

Data from two different compressors must be sent to the HC900. One uses Profibus and the other uses Modbus RS-485.
As far as I know, the Profibus slave signal must be converted to Mobdus with a gateway, but then I get lost.

Should the Profibus converted signal and the Modbus RS485 be connected to the remote switch?
In the control room they must be connected to the HC900 serial port using some ethernet/serial converter after the switch?
Thanks in advance

 

[danw2]

remote rack:
The remote racks use their own dedicated ethernet port on the controller, which is separate from the ethernet port used for Modbus, OPC, or FTP communications.

The small print in the specs say that Honeywell needs its remote rack ethernet communications on its own dedicated ethernet network. Otherwise, update rates are not guaranteed. It appears that some delay is tolerable (since switches store and forward, some delay is inevitable), as the spec reads:

"via a dedicated Ethernet 10/100Base-T connection at up to 300 meters (984 feet) between the controller and the most remote rack using two Ethernet switches."

What's the limit? Who knows? It's not published.

Profibus:
Neither the Profibus compressor nor the RS-485 compressor can connect directly to the remote rack.

Remote rack scanners do not support external device communications protocols. External devices must connect directly to or communicate over serial or ethernet to the HC900 controller.

Honeywell uses the Prolinx Gateway Profibus/Modbus converter model 5104-MCM-PDPM which functions as a Profibus DP master to communicate with the compressor, a Profibus slave. The Prolinx Gateway appears as a Modbus slave to the HC900 controller's Modbus master using one of the controller's RS-485 serial ports.

In the Prolinx, parameters have to be mapped to Modbus registers. In the HC controller, Modbus Read blocks are configured to fetch the values from the Prolinx; Modbus
Write blocks are configured to write values to the Prolinx Gateway.

You don't say what your topology is. It isn't clear where the compressors are located. One at remote rack,
one locally? Both local? Both remote?

Conversion from RS-485 to ethernet depends on where the remote devices are located.

If the 485 devices are local to the controller, you can wire 485 directly to controller's serial port.

If the 485 devices are remote, then convert 485 to ethernet with a Modbus-specific serial server.

 

[fdomin]

dawn2,
Thanks for your answer.
Both compressors will be remote to the controller. I read about the Prolinx gateway, so you are confirming it, but how is it connected?

After 485/ethernet conversion, should it be connected to the ethernet switch? This switch should concentrate data from the remote rack, the 485 conversion and the Prolinx gateway?
(See scheme below)

remote rack-----|
|-----eth/fo****fo/eth.-----hc900
485/ethernet----|
|
PFbus gateway--|
switch
ethernet

At HC900 site, is it posible to directly connect data from the compressors via ethernet or it must be reconverted to serial?

 

[danw2]

Your diagram will NOT work as shown. Serial RS-485 is not ethernet. There's no way to connect RS-485 directly to an ethernet switch.

1) You can convert from RS-485 to ethernet with a Modbus ethernet serial server, like a Lantronix DR-IAP,

http://www.lantronix.com/device-networking/external-device-servers/xpress-dr_dr-iap.html

or a B&B

http://www.bb-elec.com/Subcategory.asp?SubCategoryId=783&Trail=1&TrailType=Top

or a Digi-One IAP

http://www.digi.com/products/serialservers/digioneiap.jsp#overview

remote rack-----|
|-----eth/fo****fo/eth.-----hc900
|
-ethernet-
Modbus ethernet serial server
-RS-485-
|
485/ethernet----|
|
PFbus gateway--|

2) RS-485 can also be converted to FO,

http://www.bb-elec.com/productsubcat.asp?MainCategoryId=11&Trail=2&TrailType=Top

but that would need an "FO switch" or FO hub. I'm out of my depth here.

3) >At HC900 site, is it posible to directly connect data from the compressors via ethernet or it must be reconverted to serial?

Yes, as long as the RS-485 starts out as Modbus, the HC900 can talk Modbus TCP (master) on its ethernet port. However if the RS-485 starts out as some ASCII protocol, no.

 

[fdomin]

Thanks danw2!

Your help was of great value.

PS: when I stated 485/ethernet i meant some type of conversion.