[Slpe] and [Icpt] value exist for:
- I/O modules (PX Modular and PX Compact)
These values impact signal type (the I/O module). - Siemens field devices
These values affect the combination of Slpe and Icpt values for the signal type, the field device and its measurement and positioning range. XWP automatically enters these values, and they can be changed there, e.g., to consider the line resistance of a sensor or to describe a third-party sensor. - BACnet referencing
- PPS2 interface
The combined values [Slpe] and [Icpt] can be calculated as follows from individual values for signal type (I/O module) and characteristic curve (field device):
Siemens Building Technologies field devices: XWP automatically enters the combined values [Slpe] and [Icpt] (for the signal type, the field device and its measurement or positioning range) on the I/O block.
Third-party field devices: You can calculate the value [Slpe] and [Icpt] using the Intercept Calculator.
[Slpe] and [Icpt] Analog Input
TX- and PT-I/O modules PX modular
In the Desigo PX modular automation stations, the analog input block is used with the following TX-I/O and PT-I/O modules:
Signal type measurement | Description | Standard measuring range | Resolution on the bus | Value range on the bus | [Slpe] | [Icpt] |
|---|---|---|---|---|---|---|
R1K | LG-Ni 1000 | -50 … 150 °C | 1/100 °C | -5000 ... 15000 | 0.01 | 0 |
P100 | Pt100 | 0 … 250 Ohm | 1/100 Ohm | 0 ... 25000 | 0.01 | 0 |
R250 | Resistance | 0 … 250 Ohm | 1/100 Ohm | 0 ... 25000 | 0.01 | 0 |
Pt100_4 | Pt100 | -50 ... 600 °C | 1/100 °C | -5000 ... 40000 | 0.01 | 0 |
P1K | Pt1000 | 0 … 2 500 Ohm | 1/10 Ohm | 0 ... 25000 | 0.1 | 0 |
R2K5 | Resistance | 0 … 2 500 Ohm | 1/10 Ohm | 0 ... 25000 | 0.1 | 0 |
T1 | PTC sensor | -50 ... 150 °C | 1/100 °C | -5000 ... 15000 | 0.01 | 0 |
Ni1K | LG-Ni 1000 | -50 ... 180 °C | 1/100 °C | -5000 ... 18000 | 0.01 | 0 |
Pt1K375 | Pt1000 (NA) | -50 ... 180 °C | 1/100 °C | -5000 ... 18000 | 0.01 | 0 |
Pt1K385 | Pt1000 (EU) | -50 ... 600°C | 1/100 °C | -5000 ... 60000 | 0.01 | 0 |
NTC10K | NTC sensor | -40 ... 115 °C | 1/100 °C | -5000 ... 11500 | 0.01 | 0 |
NTC100K | NTC sensor | -40 ... 125 °C | 1/100 °C | -5000 ... 12500 | 0.01 | 0 |
U10 | DC 0 ... 10V | 0 … 10 Volt | 1/1000 V | 0 ... . 10000 | 0.001 | 0 |
I420 | DC 4 ... 20mA | 4 … 20 mA | 1/1000 mA | 4000 ... 20000 | 0.001 | 0 |
I25/020 (Shunt 200 Ohm) | DC 0 ... 25mA | 1 … 5 mA | 1/1000 V | 0 ... 5000 | 0.001 | 0 |
I25/020 (Shunt 100 Ohm) | DC 0 ... 25mA | 0 … 10 mA | 1/500 V | 0 ... 5000 | 0.002 | 0 |
I25/020 (Shunt 50 Ohm) | DC 0 ... 25mA | 0 … 20 mA | 1/250 V | 0 ... 5000 | 0.004 | 0 |
I25/020 (Shunt 40 Ohm) | DC 0 ... 25mA | 0 … 25 mA | 1/200 V | 0 ... 5000 | 0.005 | 0 |
I25/020 TX-I/O* | DC 0 ... 20mA*) | 0 ... 20 mA* | 1/1000 mA | 0 ... 20000 | 0.001* | 0 |
U10 (Shunt 400 Ohm) TX-I/O* | DC 0 ... 25mA*) | 0 ... 25 mA* | 1/1000 V | 0 ... 10000 | 0.0025* | 0 |
Key
* | TX-I/O modules support only 0 ... 20 mA. For a range of 0 ... 25 mA, use the shunt for 400 Ohm (0.1%, 1 W) and measure the voltage with U10. |
I/O configuration PX Compact
The analog input block is used in the Desigo PX Compact PXC10 TL to PXC52 automation station in cases where an LG Ni1000 sensor (signal type R1K) or DC 0…10 V (U10) is connected to device terminals X1…X16 of Module 001.
The following information results:
Signal type measurement | Description | Standard measuring range | [Slpe] | [Icpt] |
|---|---|---|---|---|
R1K | LG-Ni 1000 | -50…150 °C | 0.01 | 0 |
U10 | DC 0…10V | 0…10 Volt | 0.001 | 0 |
BACnet referencing
Reference to a value in another BACnet object. As the referenced value is already available as a converted or resulting value, no conversion is required, that is, [Slpe] must be defined as 1 and [Icpt] as 0.
PPS2 interface
The measured value from a room unit connected via the PPS2 interface. In the analog input block, only Objects 24 (setpoint correction) and 40 (room temperature) may be used. As the value is already available as a converted or referenced value, no conversion is required, that is, [Slpe] must be defined as 1 and [Icpt] as 0.
[Slpe] and [Icpt] Analog Output
I/O modules PX modular
In the PX modular automation stations, the analog output block is used with the following signal types:
Signal type positioning | Description | Standard measuring range | [Slpe] | [Icpt] |
|---|---|---|---|---|
Y10S | DC 0…10 V | 0 … 10 V | 100 | 0 |
Y420 | DC 4…20 mA | 4 … 20 mA | 160 | 4000 |
Y250T (P-bus)* | Three-point | AC 24…250 Volt | 2.55* | 0 |
Y250T (Island bus)* | Three-point | AC 24…250 Volt | 100* | 0 |
Key
* | Value [Slpe] for Y250T is not a physical value, but rather a special code controlling output of the AO to two relay outputs. This code differs between P-bus and island bus. |
I/O configuration PX Compact
The analog output block is used in the PX compact automation stations, when valves or actuators with DC 0…10 V control signals, signal type Y10S, are connected to device terminals Y1…Y8 of Module 004.
Signal type positioning | Description | Standard measuring range | [Slpe] | [Icpt] |
|---|---|---|---|---|
Y10S | DC 0…10 V | 0 … 10 V | 1000 | 0 |
PPS2 interface
Transfer of an analog control command to a room unit connected via the PPS2 interface. Only Object 195 (= Room temperature display) can be used in the analog output block. As the value is already available as a converted or referenced value, no conversion is required, that is, [Slpe] must be defined as 1 and [Icpt] as 0.
Line resistance with [Icpt]
For analog inputs (measurement of temperatures or resistances), most signal types are calibrated at a line resistance of 1 Ohm. The [Icpt] can be changed at the AI block if the line resistance deviates strongly from 1 Ohm.
Measuring resistances (internal resolution = 1/10 Ohm):
Line resistance | [Slpe] | [Icpt] | Delta slope | Delta intercept |
|---|---|---|---|---|
P1K (Pt1000) | ||||
0 Ohm Default = 1 Ohm 2 Ohm 3 Ohm | 0.0259740 0.0259740 0.0259740 0.0259740 | -259.480519 -259.740260 -260.000000 -260.259740 | 0 0 0 0 | 0.259740 0 -0.259740 -0.519481 |
R2K5 P1K (0...2500 Ohm) | ||||
0 Ohm Default = 1 Ohm 2 Ohm 3 Ohm | 0.1 0.1 0.1 0.1 | 1 0 -1 -2 | 0 0 0 0 | 1 0 -1 -2 |
R250 | ||||
0 Ohm Default = 1 Ohm 2 Ohm 3 Ohm | 0.01 0.01 0.01 0.01 | 1 0 -1 -2 | 0 0 0 0 | 1 0 -1 -2 |
R250 P100 (0...250 Ohm)* | ||||
0 Ohm Default = 1 Ohm 2 Ohm 3 Ohm | 0.01 0.01 0.01 0.01 | 0 -1 -2 -3 | 0 0 0 0 | 0 -1 -2 -3 |
Key
* | PT-I/O modules | P100 is a four-wire type | Default line resistance = 0 Ohm Line resistance not compensated |
| TX-I/O modules with island bus integration | Pt100_4 is a four-wire type | Default line resistance = 0 Ohm Line resistance not compensated |
|
| R250 is a two-wire type | Default line resistance = 1 Ohm |
| TX-I/O modules with BIM integration | Pt100_4 is a four-wire type | Default line resistance = 0 Ohm Line resistance not compensated |
|
| R250 is a two-wire type, but must be connected to four terminals using bridges | Default line resistance = 0 Ohm |
Measuring temperature (internal resolution = 1/100 °C):
Line resistance | [Slpe] | [Icpt] | Degrees per Ohm | Degrees per Ohm |
|---|---|---|---|---|
Pt 1K 385 |
|
| 3.85 | 0.259740 |
0 Ohm Default = 1 Ohm 2 Ohm 3 Ohm | 0.01 0.01 0.01 0.01 | 0.259740 0 -0.259740 -0.519481 |
|
|
Pt 1K 375 |
|
| 3.75 | 0.266667 |
0 Ohm Default = 1 Ohm 2 Ohm 3 Ohm | 0.01 0.01 0.01 0.01 | 0.266667 0 -0.266667 -0.533333 |
|
|
Ni1K |
|
| 5 | 0.2 |
0 Ohm Default = 1 Ohm 2 Ohm 3 Ohm | 0.01 0.01 0.01 0.01 | 0.2 0 -0.2 -0.4 |
|
|
T1 |
|
| 9.57 10.39 11.31 12.36 | 0.104450 -50...0 °C 0.096246 0...50 °C 0.088417 50...100 °C 0.080893 100...150 °C |
0 Ohm Default = 1 Ohm 2 Ohm 3 Ohm | 0.01 0.01 0.01 0.01 | 0.096246 0 -0.096246 -0.192493 |
|
|
Pt100_4 |
|
|
|
|
| Pt100 is a four-wire type, default line resistance = 0 Ohm -> Line resistance is not compensated | |||
Power surges on U10 inputs
The U10 inputs are designed for DC 0 ... 10 V with a narrower high / low tolerance range. The input reports an error when a value is stored that outside this range. A transient voltage suppressor can prevent an error message. A faulty response from the analog signal supplied by the automation station can no longer be detected.
Solution examples:
| ||
Zener diode | Voltage divider | Active setpoint adjuster BSG61 (Datasheet CE1N1992) |
| Slope must be adapted to 0...5 V (0.01 -> 0.005) Precision resistance, e.g., VISHAI MBB/SMA 0207 | Switch position 1 (Setpoint limit control) Setpoint 100% |
[Icpt] and [Slpe] for BT devices
Note for all U10 inputs
The physical inputs are designed for 0 -10V with narrow high and low tolerance limits. If a value falls outside this range, the input transmits an error signal. However, provided it is established that the peripheral devices are in order, an error signal can be prevented by using a transient voltage suppressor (10 V Zener diode and two resistors). A faulty response from the analog input signal supplied cannot subsequently be detected in the automation station.
Example of a circuit including the QAF64 which transmits more than 10 volts
