LTC2984 datasheet(42/78 Pages) AD

42 / 78 page

LTC2984

2984fb

For more information www.linear.com/LTC2984

Example: Standard 4-Wire RTD (No Rotation or RSENSE

Sharing)

Standard 4-wire RTD channel assignments follow the

general convention shown in Figure 16. Terminal 1 is

tied to ground, terminals 2 and 3 (Kelvin sensed signal)

tie to CHRTD and CHRTD-1, and the 4th terminal ties to the

sense resistor. Channel assignment data (see Table 29)

is mapped to memory locations corresponding to CHRTD.

Sense resistor channel assignments follow the general

convention shown in Figure 17. The sense resistor is tied

between CHRSENSE and CHSENSE-1, where CHRSENSE is

tied to the 4th terminal of the RTD. Channel assignment

data (see Table 37) is mapped into a memory location

corresponding to CHRSENSE.

Figure 18 shows a typical temperature measurement

system using a 4-wire RTD. In this example, a 4-wire

APPLICATIONS INFORMATION

Figure 16. 4-Wire RTD Channel Assignment Convention

Figure 17. Sense Resistor Channel Assignment Convention for

4-Wire RTDs

2984 F16

CHRTD-1

CHRTD

CHRSENSE

4TH TERMINAL TIES TO SENSE RESISTOR (CHRSENSE)

EXCITATION

CURRENT

FLOW

= CHRTD (2 ≤ RTD ≤ 20)

CHANNEL

ASSIGNMENT

2984 F17

CHRSENSE-1

CHRSENSE

RSENSE

EXCITATION

CURRENT

FLOW

= CHRSENSE (2 ≤ RSENSE ≤ 20)

CHANNEL

ASSIGNMENT

RTD’s terminals tie to GND, CH13, CH12, and CH11. The

sense resistor ties to CH11 and CH10. The sense resis-

tor and RTD share a common connection at CH11. The

RTD sensor type and configuration data are assigned to

CH13. 32 bits of binary configuration data are mapped

directly into memory locations 0x230 to 0x233 (see

Table 44). The sense resistor is assigned to CH11. The

user-programmable value of this resistor is 5000.2Ω.

32 bits of binary configuration data are mapped directly

into memory locations 0x228 to 0x22B (see Table 46).

A conversion is initiated on CH13 by writing 10001101

into the data byte at memory location 0x000. Once the

conversion is complete, the INTERRUPT pin goes HIGH

and memory location 0x000 becomes 01001101. The

resulting temperature in °C can be read from memory

locations 0x040 to 0x043 (corresponding to CH13).

LTC2984 Datasheet(PDF) 42 Page - Analog Devices

LTC2984 Datasheet(HTML) 42 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78

Datasheet Download

Link URL