Data Transfer

Does your statement that there is a fiber optic connection between the RTU and the pump station mean that the RTU can and does get data from the pump station? Over the fiber optic link?

If so, one would assume that the data from the pump station could be fetched by the RTU, and then subsequently read by the DCS. But you haven't made that same assumption. Why?

For data communication issues you must reveal more about exactly what you have and what you want to accomplish.

DCS to RTU:
What hardware layer is available? Serial RS-485. present baud rate?
What protocol is available? ?

RTU to pump station:
What hardware layer is available? Fiber optic. Fiber optic with serial ports? ethernet port?
What protocol(s) are available at the pump station and/or RTU? ?

What kind of data is at the pump station that you desire?
How is it available to the world? Modbus?

Does your statement that there is a fiber optic connection between the RTU and the pump station mean that the RTU can and does get data from the pump station? Over the fiber optic link? ----- yes theres a fiber link

2) If so, one would assume that the data from the pump station could be fetched by the RTU, and then subsequently read by the DCS. But you haven't made that same assumption. Why?---thats what i would like to know

For data communication issues you must reveal more about exactly what you have and what you want to accomplish.

DCS to RTU:
What hardware layer is available? Serial RS-485. present baud rate?
What protocol is available? ? serail interface rs485/modbus

RTU to pump station:
What hardware layer is available? Fiber optic. Fiber optic with serial ports? ethernet port? fiber optic with ethernet switch

What protocol(s) are available at the pump station and/or RTU? ? TCP/IP

What kind of data is at the pump station that you desire?Valve status transmitter readings
How is it available to the world? Modbus ---modbus

kindly clarify regarding point no 02

Regards

jose

In order to deal with the valve transmitter readings over an industrial digital communications network, the valve transmitter readings must be available in some digital format/protocol (HART, Modbus, Profibus) from a digital comm hardware port (RS-232, RS_485, ethernet).

If the protocol at one end doesn't match, protocol converters can be used. And, protocol rules must be followed, for instance, a Modbus slave cannot talk to another modbus slave; only a Modbus master can poll a Modbus slave.

If the physical layer comm links do not match, media converters (RS-232/485 converter, RS-485-to-ethernet serial server, ethernet to FO) can be used.

Either conversion task takes some configuration and effort to get it working.

If I understand your response properly, it appears that the valve status transmitter readings are available as Modbus, but what kind of physical comm port is the data available on? RS-485? ethernet? Either RS-485 or ethernet can be converted to fiber optic.

Is the valve data coming from a positioner? If so, it is most likely a Modbus slave.

Does the RTU have the capability of being a Modbus master? Given the assumption that the device with the valve data is a Modbus slave, a Modbus master is needed to poll and fetch the valve status data. And the physical comm links need to be compatible. The RTU is probably a Modbus slave to the DCS Modbus master, but that depends on how that side is configured. If the RTU is a Modbus slave, the RTU might be limited to that Modbus slave function only. Whether it can be a Modbus slave on one port (providing data to the DCS) and a Modbus master on a 2nd port (fetching valve status data) depends on the functionality of the RTU.

Based on assumptions, but can you accomplish this?

kindly check your inbox