Chapter 2. SPECIFICATIONS
2 - 7
2.5 Connection between a Pt and RTD input module
-
Number of method of connection between Pt and RTD input module are three, that is, 2-wired type, 3-
wired type and 4-wired type.
-
The resistance of the wires used to connect Pt to RTD input module should be 10
Ω
or less per wire.
The same wire (in thickness, length, and kind, etc.) should be used for each channel.
REMARK
Σ
The difference between the resistance values of the wires used should be 1
Ω
or less, or the accuracy
shown in the Table 2.2 could not be satisfied.
Connection
Method
Connection Example
Wire Conditions
2-wired type
3-wired type
4-wired type
ℵ
wire resistance
≤
10
Ω
ℑ
wire resistance
≤
10
Ω
ℜ
wire resistance
≤
10
Ω
The difference between the
resistance values of the wires
ℵ
and
ℑ
: 1
Ω
or less
The difference between the
resistance values of the wires
ℑ
and
ℜ
: 1
Ω
or less
The difference between the
resistance values of the wires
ℜ
and
ℵ
: 1
Ω
or less
[Fig. 2.3] Method of Connection between Pt and RTD Input Module
*1: RTD (Pt100 or JPt1000)
*:2: Shielded wire
- The shields of the RTD and shields of wire should be connected to the FG of the RTD input
module.