H

Hello,

Have a look at what the "Analog differential trigger" can deliver. 

Figure 1. Instruction's block symbol

Figure 2. Function diagram


Figure 3. Instruction location

Figure 4. Hover over instruction. Press "?" for help on instruction.

Hello AutoGen,

Maybe this will help you. You still have to adapt the switching hysteresis to your circumstances. But don't choose them too small. Remember that when measuring the temperature you increase the detection range from 0-1000 to a value range of -500 to 2000 .This results in display jumps and a certain inaccuracy in the last display position.

Greetings Ella_68

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Hello,

Does this not work with PT100 or am I missing something? I have PT100 measuring the Celsius degrees. The heater should be on when degrees are 0 - 35 Celsius. After 35 Celsius heater should be switched off automatically. 

I always use an AM2 RTD (6ED1 055-1MD00-0BA2) and the Emko temperature sensor (type: RTS-M06-L060-K02; -50 to +200°C).A PTC’s right to work is important.

greeting Ella_68

Hello Auto_Gen

There are four things you need to keep in mind:

1. If you use the AM2 RTD extension AM2 RTD, the recorded value (-500 to 2000) is "squeezed" by the analog input limitation of 0-1000.This means a tolerance for the last digit.

2. An analog value of 300 corresponds to 30.0°C.

3. It follows that a switching accuracy of 0.2°C cannot be achieved using simple means.In order to resolve more precisely, you need external converters that are read in via Modbus.

4. Switching to this point will, due to the slightest changes or tolerances, cause a continuous switching on/off, which will destroy the connected device after a short time.

About the program:

With B003 you set the switching point (e.g. 300 for 30°C).If this value is exceeded, the heating switches off. The hysteresis for switching on is determined by the negative offset value of block B006 (e.g. 10 for 1°C). Do the same with the cooling.

The value for switching on the cooling is the positive offset value from block B002.It is switched off when the control value (B003) is reached.

The advantage of such programming is that once the correct hysteresis values have been determined, a change must be madethe default temperature (B003), the switch-on and switch-off temperatures do not need to be reset separately. The program then does this for you.

Greetings Ella_68

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