ROC800L LACT Meter Factor

tprice1965 · Jan 18, 2022

Hello all, I am attempting to message a meter factor value from a MicroLogix 1400 processor to a ROC800L. Any help would be greatly appreciated. The meter factor is used to bias the LACT flow to match the portable LACT proving device. In the past we utilized a Linco TA1000 device that we could manually input this number into. The replacement flow computer (ROC) makes this procedure a little more difficult. Thank you in advance.

Engineerj22 · Jan 19, 2022

What communication protocol are you using? (MODBUS, ETHERNET/IP)

tprice1965 · Jan 19, 2022

Engineerj22 said:
What communication protocol are you using? (MODBUS, ETHERNET/IP)

Modbus, and when I hover over the Meter Factor field in ROCLINK 800, it has an address of TLP 25,0,15. I was told that this would require a double real tag from Logix 500...? (using a Micro 1100).

Thank you much for your help.

drbitboy · Jan 19, 2022

I doubt MicroLogix 1100 has a "double real" (I assume that means double-precision real i.e. 64-bit floating-point IEEE-754 cf. this link).

If the accuracy of a single-precision real (cf. this link) would be adequate, and the value is in the range ±3.4E+38, then you would still be able to transfer the double-precision value as four 16-bit INTs, or even just the three most-significant, 16-bit words via Modbus, and then you could transmogrify those words into a single-precision real.

If the double-precision value is an integer in the range ±2147483648, then you would be able to retrieve the full resolution into a long on the MicroLogix 1400.

tprice1965 · Jan 19, 2022

drbitboy said:
I doubt MicroLogix 1100 has a "double real" (I assume that means double-precision real i.e. 64-bit floating-point IEEE-754 cf. this link).

If the accuracy of a single-precision real (cf. this link) would be adequate, and the value is in the range ±3.4E+38, then you would still be able to transfer the double-precision value as four 16-bit INTs, or even just the three most-significant, 16-bit words via Modbus, and then you could transmogrify those words into a single-precision real.

If the double-precision value is an integer in the range ±2147483648, then you would be able to retrieve the full resolution into a long on the MicroLogix 1400.

I have heard everything from double real to double DINT

obviously no one I work with has a clue. Trying to figure out what type of tag the TLP 25,0,15 address in the ROC is, and what MODBUS address would I have to MSG from the 1100 to that ROC address.

drbitboy · Jan 19, 2022

tprice1965 said:
I have heard everything from double real to double DINT obviously no one I work with has a clue. Trying to figure out what type of tag the TLP 25,0,15 address in the ROC is, and what MODBUS address would I have to MSG from the 1100 to that ROC address.

https://www.emerson.com/documents/a...{"num":1137,"gen":0},{"name":"XYZ"},52,268,0]

I think you define the TLP-to-Modbus-register mapping in the ROC800L?

nswu1 · Jan 26, 2022

Yes you would take the TLP and add it to the MODBUS register to go out modbus to your allen bradley.

ROC800L LACT Meter Factor

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