RS Fieldbus

Hi there,

Please help

I am in Peru and commissioning a system that uses RS field bus. I am very new to RS field bus and here is the situation:

I have 4 Analog input and two Analog output devices. When I go online, on the strategy page in RS field bus, I can see all the values from my AI blocks.

I can also sent values to my AO blocks from my PLC, and actually see the value showing up on the FFLD block and CAS_IN of my AO blocks on strategy page. the problem is that the valves don't modulate.

When I put the AO blocks mode into manual mode from RS field bus, I can modulate the valves by putting values into the "OUT" of the blocks accordingly. so there is no hardware, or addressing problem. Everything seems to be fine, yet my valves don't modulate in auto mode.

Regards

Do you use subroutines?
If you do, have you enabled the subroutines?
That will kill you every time!

Sorry do you mean subroutine in RS fieldbus?

Sub routines in RS Logix, actual program.
You can have a mani program and break down your assemblies/sections in sub routines which are called from the main routine.
Not familiar with rS fieldbus, just RSLogix5000 and such.
Also, the channels must be enabled from within RSLogix for your analog cards,
a bit is set to "1" which enables that particular channel.
Not sure what kind of hardware you are using, just speculating here.

yes, I have subroutines in RSLOGIX 5000. I didn't know about the enable bit. I'll look into it.

Analog output cards must be enabled from within the software, setting the right bit to "1" will enable the channel on the card.
Setting the actual bit to "0" will disable he channel on the card.
Each channel has its onw "enable" bit.
Analog inputs may need to be setup as well, configuration, etc.
For a 1769-OF8V, analog output set to 0-10v, look under (Local:4:C = Slot 4 in this case, Local:4:C.Ch0En will be the actual bit that you use to enable Channel 0)
You will need to set the rest of it, configurationwise but I assume since you can enter values and control your outputs the configuration and (raw, engineering units and such) is already set.

EDIT: Forgot to mention that you do the enables and such from within your "Controller Tags". Just punch in "1" and the channel will be enabled.

Thanks, as you mentioned because I can see my PLC values on the strategy page, I believe my channel is already functioning.