KROHNE MFC 400 Modbus - Manual (Page 20)

5
MODBUS PROTOCOL
20
MFC 400
www.krohne.com 05/2013 - 4002525102 - AD Modbus MFC 400 R02 en
5.8.7 Zero Calibration
Due to process and installation variations that cannot be accounted for by factory calibration, it is
always good practice to perform regular zero calibrations on the sensor to ensure the accuracy
of the results.
The Coils and Registers below are required to perform a zero calibration. For further
information refer to
Zero calibration on page 29.
Modbus Function Codes "Read Coils" (0x01) and "Write Single Coil" (0x05)
Coil
Address Name Function Action Values Display
Fct. No.
2000 2000 2000 2000
(0x07D0)
Zero Calibration
Control
Start Write 1 = start zero calibration C1.1.1
Status Read 0 = zero calibration not running /
complete
1 = zero calibration in progress
-
Modbus Function Code "Read Input Registers" (0x04)
Input
Register Name Type No. of
registers Values
20000 20000 20000 20000
(0x4E20)
Zero Calibration Result Byte 1 0 = success
1 = fail – sensor not measuring
2 = fail – zero too high
20001 20001 20001 20001
(0x4E21)
Zero Calibration new "Zero Flow
Offset"
Float 2 -
Modbus Function Codes "Read Holding Registers" (0x03) and "Write Multiple Registers" (0x10)
Holding
Register Name Type No. of
registers
46000 46000 46000 46000
(0xB3B0)
Zero Calibration Value Float 2