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Chapter 4. FUNCTION BLOCKS
4.2.3 Reading the Detected Temperature Value of the Module (Single Type)
(G3F-RD3A : RTD3RD, G4FRD2A : RTD2RD)
The stand-alone type Temperature conversion value reading function block processes only one channel
of the RTD input module. If a channel is enabled then the function block outputs the detected
temperature value and its digital conversion value that is usable as a PV in the PID control module.
Function
I/O
Block
I
O
Data
Variable
Type
REQ
BOOL
Function block execution request area
- Used to request an execution of the reading function block
- If the conditions connected with this area are established while the
program is running and "0" changes into "1", the reading function block
is executed.
BASE
USINT
Base location No.
- Used to write the number of the base where the RTD input module is
loaded.
- Setting range: GM1 series(0~31), GM2 series(0~7), GM3/4 series(0-3)
SLOT
USINT
Slot location No.
- Used to write the number of the slot where the RTD input module is
loaded.
- Setting range: 0~7
CH
USINT
Area for specifying the used channel.
Settings : G3F-RD3A: 0 to 7, G4F-RD2A: 0 to 3
DONE
BOOL
Function block execution complete status
- "1" is output when the reading function block is finished with no error and
"1" remains until next execution. If an error occur, '0' is displayed and the
operation enters into the stop state.
STAT
USINT
Error status indication area
- Used to output the number of an error when it occurs during reading
function block execution.
- For description of errors, see GM Section 7.4
ALM
BOOL
Run channel error indication area
- "1" is output if error occurs for each run channel.
TEMP
IN T
Detected temperature value output area
- The CPU module reads the detected temperature value(-200.0°C to
+600.0°C) of the corresponding channel from the RTD input module and
outputs it to this area.
- The detected temperature value of each channel is 10 times than the real
temperature value.
(Example: Detected temperature value 1234 → real temperature value
123.4°C)
SCAL
INT
Digital conversion value output area
- The CPU module reads the digital conversion of the corresponding
channel from the RTD input module and outputs it to this area.
- The detected temperature value (-200.0°C to +600.0°C) of each channel
is converted into a digital value within 0 to 16000 and it is output to this
area.
- Value to be read from the output variable.
• SCAL =(the value to be read from the output variable TEMP + 2000)
• Example: Where a temperature is 234.5°C.
- The output value converted into a digital value can be used as the PV of
the PID control module.
Descriptions
2
The value to be read from the TEMP is (temperature 10),
then
2345 is the detected temperature value.
The value to be read from the SCAL is (2345 + 2000)
i.e., 8690.
4 - 4
2,
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