-14-
flame ignition systems or electrostatic precipitators are in the vicinity of the control. A more common source of
interference occurs when the control is switching inductive loads such as contactor coils, solenoids or
motors. The collapse of the magnetic field when loads such as these are switched off can create an electrical
“spike” that can cause a malfunction of the microprocessor used in the control. Even if the control doing the
switching is unaffected, a nearby control may be affected. To eliminate or minimize this problem, transient
suppressors or “snubbers” can be employed across the inductive load.
Illustration of a Typical Heater Installation in a Process Tank
CONSULT INSTALLATION AND MAINTENANCE INFORMATION FOR SPECIFIC INSTRUCTIONS
M-33-01-02 02/17/11
M-33-01-02 02/17/11
2 wire- 1000 ohm RTD TCR (alpha),
0.00385 ohm/ohm/°C
RTD Self Heating Coefficient:
5° C/w in 0.2 m/s water; 200° C/w in
1 m/s air measurement current, 0.1 to 0.2 mA
-40 to 1000°F (-40 to 538°C)
°F or °C field selectable
Set Point Range
Selectable throughout the input range
De-energize control output (No sensor short
protection with Thermocouple sensor)
Accuracy
± 0.25% span, ± 1 digit
Type 12, IP55
Face suitable for panel mounting
(#20 ga. through 1/4 thick panels)
Display
4 digit, (1/2" nominal), LED display screen
Control Function
ON/OFF Electromechanical Relays
SP1 Set Point
(reverse acting) SPDT 20A resistive@240 VAC max
1HP@240 VAC max, 1/2 HP@120VAC
Field adjustable
1° (F or C) to 99°
Memory
Nonvolatile
Supply Voltage
100 to 240 V~ ± 10%, 50-400 Hz, 13VA
• Indoor Use Only
• -20 to 140°F (-33 to 60°C)
• Max Altitude: 3000m
• Max Relative Humidity: 80%
• Pollution Degree 2
RTD 2 & 3-wire 100 ohm 0.00385 ohm/ohm/ºC or
0.00392 ohm/ohm/ºC
Thermocouples - (types J, K, T, R)
NIST Monograph 175, revision ITS-90
Current 4-20mA DC
Voltage (1-10 VDC)
Frequency (0-200 Hz, counts/second),
+/- 6 VDC p to p (up to 30VDC peak with Sw2 ON)
DE20 Specifications
Control Outputs
Standard Input
Input Range
Sensor Break or
Short Protection
Enclosure
ON/OFF
Differential
Operating
Conditions
Input Options
Equipment protected throughout by Double Insulation or Reinforced Insulation.
