Watlow EZ-ZONE PM Series - Input Signal Connections; Process Volts and Amperes Inputs; Resistance Temperature Detector (RTD) Inputs; Thermocouple and Thermistor Inputs

EZ-ZONE PM Limit Express • 13 • Install & Wiring
Note:
In the drawings below for each input notice that the Slot A connector labeling is identified.
Note:
When using a 2 wire RTD, jumper S1 and T1 together
Inputs
All inputs shown below represent input 1 (the only input) and are to be connected to slot A of the Limit Control.
Process Volts and Amperes
• 4 to 20 mA @ 100 Ω input impedance
• 0 to 10VÎ (dc) @ 20 kΩ input impedance
• Scalable
Resistance Temperature Detector (RTD)
• Platinum, 100 Ω @ 0°C
• Calibration to DIN curve (0.00385 Ω/Ω/°C)
• 20 Ω total lead resistance
• RTD excitation current of 0.09 mA typical. Each
ohm of lead resistance may affect the reading by
0.03°C.
• For 3-wire RTDs, the S1 lead must be connected
to R1.
• For best accuracy use a 3-wire RTD to compen-
sate for lead-length resistance. All three lead
wires must have the same resistance.
Thermocouple
• 2 KΩ maximum source resistance
• >20 MΩ input impedance
• 3 microampere open-sensor detection
• Thermocouples are polarity sensitive. The nega-
tive lead must be connected to S1.
• To reduce errors, the extension wire for thermo-
couples must be of the same alloy as the thermo-
couple.
Thermistor
• >20 MΩ input impedance
• 3 microampere open-sensor detection
-
+
Thermocouple
S1
R1
T1
S1
R1
S1
S2
S3
RTD
2 or 3 Wire
-
+
-
+
S1
R1
T1
S1
Process
Volts
Process
Amperes
Thermistor
S1
R1