Temperature sensor
In Circulo a specific temperature sensor port with selectable integrated pull-up resistors is available. This input port is suitable for RTD sensors because of its high input resistance (1 MΩ). Alternatively, the single-ended 5 V Analog input with an external pull-up resistor can be used as an RTD sensor input as well.
For details about using temperature sensors, please refer to our system integration guide.
A reference voltage of 5 V is supplied. The sensor’s recommended current is typically about 1 mA (please refer to the manufacturer data sheet). The pull-up resistor has to be selected according to the RTDs data sheet to ensure that the current is not higher or lower than required.
Note: Please ensure that the voltage attached to the temperature sensor input is between 0 V and 5 V.
Note: Synapticon has successfully tested PT1000 and KTY84-130.
PT100 will also work but be aware that its low resistance will result in a low accuracy so this type can’t be recommended.
In case you want to use other sensors, such as NTC, please contact support@synapticon.com.
Circulo offers three different configurable integrated pull-up resistors: 4.7 kΩ, 10 kΩ and 22 kΩ.
Depending on the type of temperature sensor, different resistors in the servo drive need to be activated. This is done internally with a multiplexer. The desired value can be selected via software through object 0x2038 subindex 3.
Attention: The ADC value is scaled to 16 bit since firmware v5.0.
Note: If you define the different resistor value for the internal ADC input, the firmware will choose the closest resistor to the specified value
The measured analog value can be calculated into a corresponding temperature by the drive itself. Details are described in Analog Input Scaling.
For details about using temperature sensors please check our System integration guide.
Specification for the single-ended temperature sensor input
|
Symbol |
Min. |
typical |
Max. |
Description |
Impact |
|---|---|---|---|---|---|
|
Vin |
0 V |
+5 V |
The input voltage between the input and GND. |
Any voltage out of this range causes saturation to the min/max ADC value. |
|
|
Vin,lim |
0 V |
+5 V |
The tolerable input voltage between the input and GND. |
Any voltage out of this range damages the analog input’s circuitry. |
|
|
Ri |
>1 MΩ |
Internal input resistance |
|||
|
Error |
-1% |
+1% |
Error in ticks |
Attention: The temperature sensor input should only be used for measuring temperatures with RTD.