FCI ST100A Series, Installation, Operation And Maintenance Manual

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ST100A Series Flow Meter OPERATION
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in the Modbus standard integer register form. And lastly registers 4111, 4112, 4113, and 4114 offer the flow totalizer as a single precision
floating point value in the Modbus standard register form. Because the Totalizer values can become a very large number, the single
precision floating point presents the data as two register groups. Group 1 called TOTALIZER 1 holds the lower count with a defaulted
count limit of 65,535.996. TOTALIZER 1 resets back to zero when the count limit is reached. Group 2 called TOTALIZER 2 holds the upper
count and it increments by 1 every time the group 1 registers reach the 65,535.996 count or the set “Totalizer Max Limit” count.
TOTALIZER 2 has a maximum count of 4,294,967,295, after which it resets back to zero.
The TOTALIZER 1 group maximum count value can be set to a lower value of the default value by the user. This is controlled by service
registers 4115 and 4116 for which values above 65,535.996 are not permitted. The default value of 65,535.996 for TOTALIZER 1 provides
a resolution 0.01 to the ST100A Series Totalizer value.
To reconstruct the double precision floating point value of the Totalizer using the single precision floating point registers do the following:
𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 ( 𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 ) = 𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 2 𝑣𝑣𝑇𝑇𝑇𝑇𝑣𝑣𝑇𝑇 × 𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 1 𝑀𝑀𝑇𝑇𝑀𝑀 𝑉𝑉𝑇𝑇𝑇𝑇𝑣𝑣𝑇𝑇 + 𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇𝑇 1 𝑣𝑣𝑇𝑇𝑇𝑇𝑣𝑣𝑇𝑇
Table 21 – ST100A Series Modbus Process Data
Variable/Parameter
Modbus Slave
Register
Data Type
1
Access
Flow (Value) 5101 Float Read
Process Variable Temp (Value) 5102 Float Read
Values – Daniel Totalizer (Value) MS 5103 Float (D)
2
Read
Extension Totalizer (Value) LS 5104 Float (D)
2
Read
Pressure (Value) 5105 Float Read
Flow MS (Value) 4101 Special1 Read
Flow LS (Value) 4102 Special1 Read
Temperature MS (Value) 4103 Special1 Read
Process Variable Temperature LS (Value) 4104 Special1 Read
Values – Integral Totalizer MS (Value) 4105 Special2 (D)
2
Read
Registers Totalizer MS2 (Value) 4106 Special2 (D)
2
Read
Totalizer LS2 (Value) 4107 Special2 (D)
2
Read
Totalizer LS (Value) 4108 Special2 (D)
2
Read
Pressure MS (Value) 4109 Special1 Read
Pressure LS (Value) 4110 Special1 Read
Totalizer Value – Totalizer 1 MS (Value) 4111 Float Read
Single Precision Totalizer 1 LS (Value) 4112 Float Read
Floating Point Totalizer 2 MS (Value) 4113 Float Read
(16 Bits) Totalizer 2 LS (Value) 4114 Float Read
Process Variables – Flow Eng. Units Code 4020 Integer Read
Engineering Unit Temp Eng. Units Code 4021 Integer Read
Codes Totalizer Eng. Units Code 4022 Integer Read
Pressure Eng Units Code 4023 Integer Read
Instrument Status Device (Sensor 1) Status Code #1 4025 Integer Read
Codes Device (Sensor 1) Status Code #2 4026 Integer Read
Notes: 1. Data Type: Special1 is a collection of discrete registers that contain a single precision (32-bit) floating point
value, and must be treated and interpreted as a single precision floating point number by the DCS or the PLC.
Special2 is a collection of discrete registers that contain a double precision (64-bit) floating point value, and
must be treated and interpreted as a double precision floating point number by the DCS or the PLC.
2. (D) indicates double precision (64 bits).