I am working on a small Fieldbus network setup with a CompactLogix L45 controller, two 1788-EN2FFR linking devices and an array of Fieldbus transmitters and three Fieldvue valve positioners. The linking devices are each controlling separate Fieldbus networks.
The problem I am having is that while I can get data from the Fieldbus networks into the PLC, anytime I try to pass data from the controller to a function block in a device, I get a "BAD: NOCOMM NO USABLE VALUE" status. So all the transmitters are passing PVs into my controller via wired connectors with PLC tags, but my controller cannot pass values into the device function blocks (ie a command signal or PV to the Fisher valve positioners). The positioners are Fisher DVC6200f Device Revision 2 DD1.
I am following the directions exactly as published in the 1788-EN2FFR manual (Document 1788-UM057A-EN pg 68) http://www.hiprom.com/Pages/Products/1788_Range/1788-EN2FFR/files/Document%20Publish/1788-UM057A-EN-P.pdf. I am constructing my function block arrangements as instructed, and then I try to model the Fieldbus function block handshaking / initialization as shown in the document, but since the values linked from the PLC to the function block are never passed to the function block and the status of these function block inputs are always BAD:NO COMM, I cannot move forward with the handshaking procedure. This situation holds true for all types of function blocks (AO,DO,PID,ISEL, etc) and all types of values (REAL,INT,BOOL) and all function block modes (AUTO, MAN, IMAN). I can circumvent the handshaking trickery and get an AO function block to go into CAS mode by linking it to a PID FB but I am still in the same boat with my input to the PID FB never making it into the block. I am trying to simply get a 0-100% travel command to the positioners (I run the PID logic in the controller), but no matter what I can't get any sort of input whatsoever into the positioner device. I have no problem linking or wiring the positioner's function block outputs to a controller tag and seeing the value in the controller, but it seems impossible to get a value from the controller to pass into the device function blocks. I can see the value update on the connector I add into the function block schematic, but the value does not pass to the function block parameter it is wired to, regardless of FB mode.
I have tried different firmware revisions on the linking devices and different DD files for the Fisher Fieldvue valve positioner and neither had any effect. I am going to try an older revision AOP for the linking device, but I am currently using the most recent one. It seems like a stretch, but I may even try an older firmware revision on the controller itself. It seems to be a communication problem, but since it is only occurring in one direction (values from controller to fieldbus device) and everything seems to work fine in the opposite direction (values from fieldbus device to controller), I am stumped. My setup is one H1 bus per linking device with 8-12 fieldbus devices on each linking device, using two 1788-PARJB junctions on each separate H1 bus network. Each separate fieldbus network is wired as single bus, single master, terminated (with the linking device being one terminator and the second junction box being the second terminator). Signal diagnostics seem ok. I have looked at the LAS schedule and the RPI rates and I can't find any obvious problems there, but I did read that communication errors could come from a timing error between the function block schedule and the comm schedule. Why that would effect communications only in one direction, I am not sure. Oh, and I am using an unmanaged switch, but even bypassing the switch and going linking device directly to the controller's ethernet module had no effect on the problem. Thanks in advance for any help.
The problem I am having is that while I can get data from the Fieldbus networks into the PLC, anytime I try to pass data from the controller to a function block in a device, I get a "BAD: NOCOMM NO USABLE VALUE" status. So all the transmitters are passing PVs into my controller via wired connectors with PLC tags, but my controller cannot pass values into the device function blocks (ie a command signal or PV to the Fisher valve positioners). The positioners are Fisher DVC6200f Device Revision 2 DD1.
I am following the directions exactly as published in the 1788-EN2FFR manual (Document 1788-UM057A-EN pg 68) http://www.hiprom.com/Pages/Products/1788_Range/1788-EN2FFR/files/Document%20Publish/1788-UM057A-EN-P.pdf. I am constructing my function block arrangements as instructed, and then I try to model the Fieldbus function block handshaking / initialization as shown in the document, but since the values linked from the PLC to the function block are never passed to the function block and the status of these function block inputs are always BAD:NO COMM, I cannot move forward with the handshaking procedure. This situation holds true for all types of function blocks (AO,DO,PID,ISEL, etc) and all types of values (REAL,INT,BOOL) and all function block modes (AUTO, MAN, IMAN). I can circumvent the handshaking trickery and get an AO function block to go into CAS mode by linking it to a PID FB but I am still in the same boat with my input to the PID FB never making it into the block. I am trying to simply get a 0-100% travel command to the positioners (I run the PID logic in the controller), but no matter what I can't get any sort of input whatsoever into the positioner device. I have no problem linking or wiring the positioner's function block outputs to a controller tag and seeing the value in the controller, but it seems impossible to get a value from the controller to pass into the device function blocks. I can see the value update on the connector I add into the function block schematic, but the value does not pass to the function block parameter it is wired to, regardless of FB mode.
I have tried different firmware revisions on the linking devices and different DD files for the Fisher Fieldvue valve positioner and neither had any effect. I am going to try an older revision AOP for the linking device, but I am currently using the most recent one. It seems like a stretch, but I may even try an older firmware revision on the controller itself. It seems to be a communication problem, but since it is only occurring in one direction (values from controller to fieldbus device) and everything seems to work fine in the opposite direction (values from fieldbus device to controller), I am stumped. My setup is one H1 bus per linking device with 8-12 fieldbus devices on each linking device, using two 1788-PARJB junctions on each separate H1 bus network. Each separate fieldbus network is wired as single bus, single master, terminated (with the linking device being one terminator and the second junction box being the second terminator). Signal diagnostics seem ok. I have looked at the LAS schedule and the RPI rates and I can't find any obvious problems there, but I did read that communication errors could come from a timing error between the function block schedule and the comm schedule. Why that would effect communications only in one direction, I am not sure. Oh, and I am using an unmanaged switch, but even bypassing the switch and going linking device directly to the controller's ethernet module had no effect on the problem. Thanks in advance for any help.
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