Watlow F4T Install & Troubleshooting
•
13
•
Chapter 2 Install and Wire
RTD
FM [M, L] A - [L, U,
Y
*
] _ _ A - A _ _ _
2-wire
RTD
T1
S1
R1
S3
S1
3-wire
RTD
T1
S1
R1
S2
S3
S1
• 2 or 3-wire platinum, 100
and 1,000 Ω @ 32°F (0°C)
calibration to DIN curve
(0.00385 Ω/Ω/°C)
• RTD excitation current
of 0.09 mA typical. Each
ohm of lead resistance
may affect the read-
ing by 2.55°C for a 100
ohm platinum sensor or
0.25°C for a 1000 ohm
sensor.
*
This option does not sup-
port 3-wire RTDs
Lead Wire Resistance
Each wire for 2-Wire
RTDs, not to exceed 10
ohms maximum.
AWG
Ohms/1000ft
14
2.575
16
4.094
18
6.510
20
10.35
22
16.46
24
26.17
26
41.62
28
66.17
Note:
3-wire RTD's self-compensate
for lead wire resistance up
to 10
Ω of wire resistance.
RTD (High Density)
FMHA - RAAA - A _ _ _
2-wire RTD
S1
R1
S2
R2
S3
R3
S4
R4
•
Platinum, 100 and 1,000 Ω @ 32°F
(0°C) calibration to DIN curve
(0.00385 Ω/Ω/°C)
• RTD excitation current of 0.09 mA
typical. Each ohm of lead resistance
may affect the reading by 2.55°C for
a 100 ohm platinum sensor or 0.25°C
for a 1000 ohm sensor (see table to
right)
Lead Wire Resistance
Each wire for 2-Wire
RTDs, not to exceed 10
ohms maximum.
AWG
Ohms/1000ft
14
2.575
16
4.094
18
6.510
20
10.35
22
16.46
24
26.17
26
41.62
28
66.17
Process
FM [M, L] A - [L, U] _ _ A - A _ _ _
T1
S1
amperes
-
+
S1
R1
volts
-
+
•
0 to 20 mA @ 100 Ω input impedance
• 0 to 10V
Î
(dc) @ 20 kΩ input impedance
• 0 to 50 mV
Î
(dc) @ 20 MΩ input impedance
• Scalable