ControLogix to RIO 2711P-RN6 module comms

Hi Guys,

I have the task of converting a large PLC5 system (14 Racks) to ControlLogix platform.

In the systems three of the Racks are PVP 1250 terminals with 2711P-RN6 RIO comms module plugged into the PVP logic module.

All these PVP's communicate with the PLC5/40 via RIO . I did convert the software as such the system is controlled by a L71 ControlLogix CPU via one 1756-RIO module and two 1756-DHRIO modules.

The migration process includes removing the PVP 's from the RIO network and redirect the comms via Ethernet.

First step is to run the whole system using the CLogix bridge. For that I dedicated on e 1756-DHRIO card as a two channel RIO scanner so the PVP 1250's RIO modules are scanned by this card.

The PVP configuration includes 8 x BT's (32 length) (full rack). Also the PVP has physical I/O with 8 Input words and 8 Output words. These were in the PLC5 configuration as physical I/O. After conversion I did add up to the CLogix I/O configuration the 2711P-RN6 card as a full rack so the software allocates the 8 x Input and 8 x Output. If I use these in the converted software as in move the N register values into the new I/O the PVP will work without changing anything in the PVP at all. Obviously the addressing in the PVP is as such for example to represent the status of a sensor I have {::[PVRIO]O:076/13} .
In the old PLC5 this was simply done by a MOV instruction moving the value of a register N11:100 into O:076. In the new Controllogix rslogix 5000 software O:076 is replaced by the "PV_RIO:O.Data[6]" tag.
To my surprise if I move the N11:100 (more like the N11[100] after conversion) into the "PV_RIO:O.Data[6]" everything seems to work perfectly.
Without changing the addressing style in the PVP ({::[PVRIO]O:076/13}).
Needless to say that I haven't done any address mapping at all so obviously this happens in the PVP 2711p-RN6 module.
In the old PLC5 user program the O:070 (Which is the first word of the Rack Rack 7 words O:070 to O:077) is not used. The same goes for all the other racks which are PVP's (Full racks) .None of these racks the first Output word is used by the user program at all.

If I try to write a value into the first output word "PV_RIO:O.Data[0]" , that value will be displayed on the PVP by a numeric data display object , but it will cycle through some other values as well. I am just wondering if somebody would happen to know what these values are and if there is some sort of manual where I could have a look at why the first Output word is written to. I think these must be status bits but not sure who'd status and what writes to them.

Apart from that everything works perfectly all the BT's(4 READ & 4 WRITE Block Transfers in the PVP comms RIO configuration) work good via msg instructions (attention to the size mismatch).

I didn't even had to change the scanner type in the PVP comms configuration RIO config tab from PLC5/40 integral to 1756-DHRIO !!!
This would be a fantastic advantage in the real world as I will not have to load new programs into the PVP's while I am doing commissioning. Even if I decide that the system can go on the CLogix platform and if something goes wrong while I am not there somebody else can revert the system back to normal (PLC5) by simply replacing the 1771 ASB adapter with the PLC5/40 .
I really hope my explanation is not too messy and superfluous.

If I try to write a value into the first output word "PV_RIO:O.Data[0]" , that value will be displayed on the PVP by a numeric data display object , but it will cycle through some other values as well.

Click to expand...

If you use Block Transfers to a RIO logical rack, the first 8 bits of the Input and Output image are used by the Block Transfer function.

What you are seeing is the data for the Block Transfer and the handshaking bits that control the data flow.

As I recall, this only affects the first 8 bits of the Input and Output images, but it's it was always my practice to not use the first discrete Word in RIO PanelView applications.

Hi Ken.Well that makes good sense. However the first Input word is used by the PLC5 user program to setermine what page the PVP terminal is on. It is used fby "Replace Display Number " connection in global tags in the PVP. looks like only the Outputs are affected. I am just wondering what happens if I disable the BT/MSG instructions in the PLC which are responsible for the bt's ? If I write a number into the "PV_RIO:O.Data[0]" this time it will not be overwritten ? if only the bt's use the first 8 bits it means that the number I place into the Tag will stay ?
I cannot try this right now but I'll update of results as soon as I tested this.

Also would you know what is happening with :
"I didn't even had to change the scanner type in the PVP comms configuration RIO config tab from PLC5/40 integral to 1756-DHRIO !!!"
So the PVP "thinks" that a PLC 5/40 is the one which is scanning the RIO network. While it is not .It is the 1756-DHRIO. I am a little bit worried that if i don't change the scanner I might have issues under certain circumstances. while not changing it will give e a very big advantage.