Toshiba 8-Channel RTD Input RT318 User manual

RT318
1
8-channel RTD input
Type RT318
Category RTD ( Resistance Temperature Detector ) input
Resistance temperature
detectors Pt100
Measuring method Three-wire system
Load current 1 mA
Temperature measurement
range -50°to +270°C (-58°to +518°F)
Converted data 800 to 4000
Input channel 8 channels / module
Insulation Photo-coupler insulation (not isolated between the channels)
Conversion rate 400 ms / 8 channels
Resolution 12 bits / 0.025 % ( 0.1 °C / count )
Wire resistance correction
range Within 4Ω
Overall accuracy ±0.3 %(at 25 °C)
Tepaerature drift ±100 ppm / °C
Internal current consumption 5 Vdc, 600 mA or less
Insulation resistance 10 MΩ(500 Vdc)
Withstand voltage 500 Vac, 1 minutes ( between internal and external circuits)
Weight 500 g
Internal circuit
Internal circuit
Buffer
memor
y
5 Vdc
+15V
-15V
0V
AMP
Input filter
1A
1B
1C
1G
PC : Photo-coupler
CH1
CH8
8A
8B
8C
8G
Multiplexer
DC/DC
AG
AG
Rref
Rref
ADC PC
Current source
1 mA
1 mA
Wire break
detection PC

RT318
2
Terminal connections
Terminal
No. Terminal name Function
1 (NC) No Connection
2 (NC) ( do not connect any wire )
3 (NC)
4 (NC)
5 (NC)
6 (NC)
7 1A
8 1B RTD input channel 1
9 1C
10 1G
11 2A
12 2B RTD input channel 2
13 2C
14 2G
15 3A
16 3B RTD input channel 3
17 3C
18 3G
19 4A
20 4B RTD input channel 4
21 4C
22 4G
23 5A
24 5B RTD input channel 5
25 5C
26 5G
27 6A
28 6B RTD input channel 6
29 6C
30 6G
31 7A
32 7B RTD input channel 7
33 7C
34 7G
35 8A
36 8B RTD input channel 8
37 8C
38 8G
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
33
35
37
N.C.
N.C.
N.C.
1B
1G
2B
2G
3B
3G
4B
4G
5B
5G
6B
6G
7B
7G
8B
8G
N.C.
N.C.
N.C.
1A
1C
2A
2C
3A
3C
4A
4C
5A
5C
6A
6C
7A
7C
8A
8C

RT318
3
(1) Status indicator LEDs (PWR/FLT/RUN)
1) PWR
PWR will be lit in normal state of analog power supply, and will not be lit in abnormal state.
2) FLT
FLT will be lit if an error has occurred in the module.
3) RUN
RUN will be lit in normal state of the module, and will not be lit in abnormal state.
(2) Unused terminals
(3) RTD input terminals (1A/1B/1C/1G to 8A/8B/8C/8G)
These terminals will be connected with external RTD signals.
Name Lit ●Not lit ○
PWR Normal state abnormal state
FLT Error occurred Normal state
RUN Normal state abnormal state
(2)
(3)
(1)

RT318
4
If measurement values are unstable due to noise influences, change the grounding for
the shield in the following order for stable measurement.
(1)
(2)
(3)
How to wire
To minimize the influences of the wire resistance, be sure the wire
length to be same of each cable from the terminal nA, nB or nC to
RTD.
Supplementary
nA
nB
nC
nG
RTD
(Pt100)
AG
FG
Internal circuit side
Shielded twisted cable
RTD : Resistance
Temperature Detector
n : Channel number
AG : Analog ground
FG : Frame ground
RTD
(Pt100)
AG
Internal circuit side
Shielded twisted cable
nA
nB
nC
nG FG
RTD
(
Pt100
)
AG
nA
nB
nC
nG FG
Internal circuit side
Shielded twisted cable
RTD
(Pt100)
AG
nA
nB
nC
nG FG
Internal circuit side
Shielded twisted cable