Vega VEGADIF 85 - Modbus Host Configuration; Deviation Calculation and Dimensions

88
11 Supplement
VEGADIF 85 • Modbus and Levelmaster protocol
53571-EN-230814
11.6 CongurationoftypicalModbushosts
Fisher ROC 809
B
COM
Z
Y
A
(Rx/Tx -)
(Rx/Tx +)
2
3
+8 +30
Vdc
to
GND
56
7
834
1 2 = Power supply 3 4 = Modbus Data 5 6 = Power supply 7 8 = Modbus Data
IN OUT
Status
o on
addr.
OUTIN
2
1
Fig. 47: Connection of VEGADIF 85 to RTU Fisher ROC 809
1 VEGADIF 85
2 RTU Fisher ROC 809
3 Voltage supply
Parameters for Modbus Hosts
Parameter Value Fisher
ROC 809
Value ABB Total
Flow
Value Fisher
Thermo Elec-
tron Autopilot
Value Fisher
Bristol Control-
Wave Micro
Value Scada-
Pack
Baud Rate 9600 9600 9600 9600 9600
Floating Point
Format Code
0 0 0 2 (FC4) 0
RTU Data Type Conversion Code
66
16 Bit Modicon IEE Fit 2R 32-bit registers
as 2 16-bit reg-
isters
Floating Point
Input Register
Base Number
0 1 0 1 30001
The basic number of the input registers is always added to the input register address of VEGADIF
85.
This results in the following constellations:
•
Fisher ROC 809 - Register address for 1300 is address 1300
•
ABB Total Flow - Register address for 1302 is address 1303
•
Thermo Electron Autopilot - Register address for 1300 is address 1300
•
Bristol ControlWave Micro - Register address for 1302 is address 1303
•
ScadaPack - Register address for 1302 is address 31303
11.7 Calculation of the total deviation
The total deviation of a pressure transmitter indicates the maximum measurement error to be ex-
pected in practice. It is also called maximum practical deviation or operational error.
According to DIN 16086, the total deviation F
total
is the sum of the basic deviation F
perf
and the long-
term stability F
stab
:
F
total
=F
perf
+F
stab
The basic deviation F
perf
in turn consists of the thermal change of the zero signal and the output
span F
T
(temperature error) as well as the deviation F
Kl
: