Omron CPM1 - PROGRAMING MANUAL 02-2001 Programming Manual page 223

Temperature Sensor Units
Startup Operation
25313
(Always ON Flag)
Handling Unit Errors
Programming Example 1
clude one digit after the decimal point are stored without the decimal point, i.e.,
10 times the actual value is stored. Some examples are provided in the following
table.
Input
Unit: 1
Unit: 0.1
If the input temperature exceeds the range that can be converted, the converted
temperature data will be held at the maximum or minimum value in the range. If
the input temperature exceeds the range by more than a specified amount, the
open-circuit detection function will detect an open-circuit and the converted tem-
perature data will be set to 7FFF. The open-circuit detection function will also
operate if the cold junction compensator is faulty. The open-circuit detection
function will be automatically cleared and normal input temperature conversion
will begin automatically when the input temperature returns to the convertible
range.
After power is turned ON, it will require approximately 1 s before the first data is
converted. The following instructions can be placed at the beginning of the pro-
gram and then IR 02000 can be used to delay reading converted data until con-
version is actually begun.
25506 (=)
Note Input data will be 7FFE until actual conversion starts.
If an error occurs in an Expansion Unit, the Error Flags in AR 0200 to AR 0204
will be turned ON ( AR 0200 to AR 0202 for the CPM1A/CPM2A). Refer to page
572 for details. The addresses of the Error Flags are in order that the Expansion
Units are connected in the PC, with AR 0200 used for the Expansion Unit closest
to the CPU Unit. Use these flags in the program when it is necessary to detect
errors.
When an error occurs in a Temperature Sensor Unit, converted temperature
data will be 7FFF.
Note The status of AR 0200 to AR 0204 will not change for the open-circuit detection
function.
The following programming example shows how to convert the input data from 2
temperature sensor inputs to BCD and store the result in DM 0000 and
DM 0001. The following system configuration is used.
K or J 850 0352 Hex
–200
K, J, Pt100 or 10
JPt100
CMP (20)
User flag indicating that temperature data
001
conversion has begun.
#7FFE
02000
User-defined flag indicating that initializa-
tion has been completed
Section
Data conversion examples
FF38 Hex
500.0 5000 1388 Hex
–20.0 –200 FF38 Hex
–200.0 –2000 F830 Hex
3-2
203