Siemens SIMATIC ET 200SP Manual page 19

Parameters/address space
4.1 Measurement types and measuring ranges
Special features when using PTC resistors
PTCs are suitable for monitoring temperature and as thermal protection devices for complex
drives or transformer windings.
● Choose "Resistor (2-wire)" and "PTC" in the parameter assignment.
● Connect the PTC to the 2-wire connection technology.
● Use the PTC resistors, type A (PTC thermistor) in accordance with DIN/VDE 0660,
part 302.
● If "Underflow" diagnostics is enabled, a "Violation of low limit" diagnostics is generated for
resistance values < 18 Ω, indicating a short-circuit.
● Sensor data for the PTC resistor:
Table 4- 2
Switching points
(RRT-5) °C
(RRT+5) °C
(RRT+15) °C
Measuring voltage/
voltage at the PTC
Below 23 kΩ
1
18
Using PTC resistors
Property Technical specifica-
tions
Behavior with rising temperature
< 550 Ω
550 Ω to 1650 Ω
> 1650 Ω
Behavior with falling temperature
> 750 Ω
750 Ω to 540 Ω
< 540 Ω
Reaction to short-circuit
< 18 Ω
Max. 550 Ω
min. 1330 Ω
min. 4000 Ω
Max. 7.5 V
Normal range:
SIMATIC S7: Bit 0 = "0", Bit 2 = "0" (in the PII)
•
Prewarning range:
SIMATIC S7: Bit 0 = "0", Bit 2 = "1" (in the PII)
•
Response range:
SIMATIC S7: Bit 0 = "1", Bit 2 = "0" (in the PII)
•
Response range:
SIMATIC S7: Bit 0 = "1", Bit 2 = "0" (in the PII)
•
Prewarning range:
SIMATIC S7: Bit 0 = "0", Bit 2 = "1" (in the PII)
•
Normal range:
SIMATIC S7: Bit 0 = "0", Bit 2 = "0" (in the PII)
•
SIMATIC S7: Bit 7 (IB x+1) = "1", Bit 0 = "0" and
•
Bit 2 = "0"
TNF = Rated response temperature of the sensor
(according to DIN/VDE 0660)
1
Analog input module AI 8xRTD/TC 2-wire HF (6ES7134-6JF00-0CA1)
Comment
Manual, 09/2018, A5E32942580-AB