drummin89
Member
At the plant I work at we received in a machine that uses a Siemens IM151-8 PLC. 99.8% of the equipment in our plant is Allen Bradley, the other .1% is this siemens PLC (and the other .1% is "black box" PLCs).
Anyways I've been digging though the code on the siemens PLC to both learn how to program a siemens and so we can possibly copy the program over to and swap in an Allen Bradley.
There is code in the siemens PLC to control the pressure of 1 giant spinning roll against another giant spinning roll using 2 hydraulic cylinders. The hydraulic cylinders are actuated using 2 24vdc PWM servo valves. These 2 valves are controlled using an amplifier module that takes 2 4-20ma signals from the PLC and converts it to PWM signal for the valves.
I am trying to understand the code for converting a pressure setpoint as set through an HMI to a 4-20ma output to the valve amplifier.
I attached some screen shots of 2 networks that I don't understand what is happening.
I found a PDF of STL's http://www.plcdev.com/files/plcdev/STL-cheat-sheet-by-alphabet.pdf and tried figuring it out
How I understand Network 22.
Anyways I've been digging though the code on the siemens PLC to both learn how to program a siemens and so we can possibly copy the program over to and swap in an Allen Bradley.
There is code in the siemens PLC to control the pressure of 1 giant spinning roll against another giant spinning roll using 2 hydraulic cylinders. The hydraulic cylinders are actuated using 2 24vdc PWM servo valves. These 2 valves are controlled using an amplifier module that takes 2 4-20ma signals from the PLC and converts it to PWM signal for the valves.
I am trying to understand the code for converting a pressure setpoint as set through an HMI to a 4-20ma output to the valve amplifier.
I attached some screen shots of 2 networks that I don't understand what is happening.
I found a PDF of STL's http://www.plcdev.com/files/plcdev/STL-cheat-sheet-by-alphabet.pdf and tried figuring it out
How I understand Network 22.
- Load DB11.DBW176 (Left Pressure Setpoint, as set through HMI)to ACC2???
- Convert value in ACC2 from Integer to Double Integer
- Convert value in ACC2 from Double Integer to Floating Point
- Load 1 to ACC1
- Divide ACC2 by ACC1 (so divide setpoint by 1)
- Transfer result to DB11.DBD140
- Load DB11.DBD140
- Transfer to Pressure Left (In german its Solldruck_Links_Steuer)
- Load Pressure Left to ACC2
- Load 8.00000 to ACC1
- Divide ACC2 by ACC1 (so divide Pressure Left by 8.0000000)
- Load 2.76480000 to ACC1
- Multiply ACC1 by ACC2 (2.76480000 by previous result)
- Round result
- Transfer result to Pressure Left Scaled
- Load Pressure Left Scaled to ACC2
- Transfer Pressure Left Scaled to Output Pressure Roll Left