I have tried to solve this requirement on my own, but have not made progress all day.
The requirement is to place the scaled output from a Newport PD-25-TC process controller in an accessible register of a GE 90/30 311 plc.
The 90/30 does NOT support FPD.
The DP-25 has scalable analog Current output
This is a Temperature application over the range of -30C to +100C
The DP-25 provides set points and PID functions for an existing process tool. The data in the plc is for other process functions. The DP-25 is performing it's function PERFECTLY, There is no desire to replace the device in the process system, Only to have it's data in the plc.
PD-25 scaling is set for 4mA =-30C, and 19.99mA=100C
Output is enabled, and set to Current
An IC695ALG221 Analog input card is in the 90/30 and set without connection jumpers, thus enabling 4-20mA input. According to GE, this card sends 0-32000 counts to %AI over the full input span 4-20mA
Logic is
raw data in at %AI1 MOVE to %R1
%R1 SUBTRACT DINT 7385 (intercept) and output to %R3
%R3 MULT DINT by 13000 (130 scaled span keeping xx.xx significant digits)
output to %R5
%R5 DIVIDE DINT by 32000 (raw span) output to %R7
%R7 should be the desired number. But it's off but 1.6 degrees, quite constant over a test range of 0 C (ice water) and around 35 C .
I don't see where the scaling conversion is failing me..If I could I would correct it ;-)
The useful tutorial presented here http://www.plctalk.net/qanda/showthread.php?t=15069 has been studied at length.
The 7385 intercept was confirmed using the handi spreadsheet provided in the final post to that thread. Thanks!
I still must be missing something.
Second thoughts and opinions welcome!
Cheers
Cal
Controller reference"
http://www.omega.com/manuals/manualpdf/MQS3732.pdf
The requirement is to place the scaled output from a Newport PD-25-TC process controller in an accessible register of a GE 90/30 311 plc.
The 90/30 does NOT support FPD.
The DP-25 has scalable analog Current output
This is a Temperature application over the range of -30C to +100C
The DP-25 provides set points and PID functions for an existing process tool. The data in the plc is for other process functions. The DP-25 is performing it's function PERFECTLY, There is no desire to replace the device in the process system, Only to have it's data in the plc.
PD-25 scaling is set for 4mA =-30C, and 19.99mA=100C
Output is enabled, and set to Current
An IC695ALG221 Analog input card is in the 90/30 and set without connection jumpers, thus enabling 4-20mA input. According to GE, this card sends 0-32000 counts to %AI over the full input span 4-20mA
Logic is
raw data in at %AI1 MOVE to %R1
%R1 SUBTRACT DINT 7385 (intercept) and output to %R3
%R3 MULT DINT by 13000 (130 scaled span keeping xx.xx significant digits)
output to %R5
%R5 DIVIDE DINT by 32000 (raw span) output to %R7
%R7 should be the desired number. But it's off but 1.6 degrees, quite constant over a test range of 0 C (ice water) and around 35 C .
I don't see where the scaling conversion is failing me..If I could I would correct it ;-)
The useful tutorial presented here http://www.plctalk.net/qanda/showthread.php?t=15069 has been studied at length.
The 7385 intercept was confirmed using the handi spreadsheet provided in the final post to that thread. Thanks!
I still must be missing something.
Second thoughts and opinions welcome!
Cheers
Cal
Controller reference"
http://www.omega.com/manuals/manualpdf/MQS3732.pdf