Linear Technology LTC2983 - Page 27

LTC2983
27
2983fc
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Table 22. Thermocouple #1 Channel Assignment (Type K, Cold Junction CH
2
, Single-Ended, 10µA Open-Circuit Detect)
CONFIGURATION
FIELD
DESCRIPTION # BITS BINARY DATA MEMORY
ADDRESS 0x200
MEMORY
ADDRESS 0x201
MEMORY
ADDRESS 0x202
MEMORY
ADDRESS 0x203
(1) Thermocouple
Type
Type K 5 00010 0 0 0 1 0
(2) Cold Junction
Channel Pointer
CH
2
5 00010 0 0 0 1 0
(3) Sensor
Configuration
Single-Ended,
10µA Open-Circuit
4 1100 1 1 0 0
Not Used Set These Bits to 0 6 000000 0 0 0 0 0 0
(4) Custom
Thermocouple
Data Pointer
Not Custom 12 000000000000 0 0 0 0 0 0 0 0 0 0 0 0
Table 23. Diode Channel Assignment (Single-Ended 3-Reading, Averaging On, 20µA/80µA Excitation, Ideality Factor = 1.003))
CONFIGURATION
FIELD
DESCRIPTION # BITS BINARY DATA MEMORY
ADDRESS 0x204
MEMORY
ADDRESS 0x205
MEMORY
ADDRESS 0x206
MEMORY
ADDRESS 0x207
(1) Sensor Type Diode 5 11100 1 1 1 0 0
(2) Sensor
Configuration
Single-Ended,
3-Reading,
Average On
3 111 1 1 1
(3) Excitation
Current
20µA, 80µA,
160µA
2 01 0 1
(4) Ideality Factor 1.003 22 0100000000110001001001 0 1 0 0 0 0 0 0 0 0 1 1 0 0 0 1 0 0 1 0 0 1
Table 24. Thermocouple #2 Channel Assignment (Type T, Cold Junction CH
2
, Differential, 100µA Open-Circuit Detect)
CONFIGURATION
FIELD
DESCRIPTION #
BITS
BINARY DATA MEMORY
ADDRESS 0x20C
MEMORY
ADDRESS 0x20D
MEMORY
ADDRESS 0x20E
MEMORY
ADDRESS 0x20F
(1) Thermocouple
Type
Type T 5 00111 0 0 1 1 1
(2) Cold Junction
Channel Pointer
CH
2
5 00010 0 0 0 1 0
(3) Sensor
Configuration
Differential,
100µA Open-
Circuit Current
4 0101 0 1 0 1
Not Used Set These Bits
to 0
6 000000 0 0 0 0 0 0
(4) Custom
Thermocouple
Data Pointer
Not Custom 12 000000000000 0 0 0 0 0 0 0 0 0 0 0 0
APPLICATIONS INFORMATION
into memory locations 0x20C to 0x20F (see Table24). A
conversion is initiated on CH1 by writing 10000001 into
memory location 0x000. Both the Type K thermocouple
and the diode are measured simultaneously. The LTC2983
calculates the cold junction compensation and determines
the temperature of the Type K thermocouple. Once the
conversion is complete, the INTERRUPT pin goes HIGH
and memory location 0x000 becomes 01000001. Similarly,
a conversion can be initiated on CH4 by writing 10000100
into memory location 0x000. The results (in °C) can be
read from memory locations 0x010 to 0x013 for CH1 and
0x01C to
0x01F for CH4.