temperture control with a plc

[cool hand 0]

Hi Guys i have a project to control an SSR with a 0-10Volt output, from a Horner PLC with a J Type thermocouple input how do i set this up and scale the output

[Crossbow 295]

Depends on the PLC type. For example, the Mitsubishi temperature inputs are scaled. So you don't need to do anything to read a temperature. I am sure others are the same. Analog output is just writing a numeric value within the specified scale of the analog output module. As an example, if the module wants 0-4000 to mean 0-10VDC, then you would put in a 2000 to get 5VDC out.

[Furnaceman 0]

I design and supply combustion control systems using exclusively Horner APG kit. Horner inputs are scaled temperature x10 so 200 degrees is 2000 counts. If you are using a PID block to do the control, you need to scale this to 0 - 32000 for the PV, then the screen entry also needs to be scaled to 0-32000 for the SP. The control variable output appears as 0 - 32000 also, and this needs to be scaled to suit the particular output module you are using. For example, the SmartRail modules need 0-4000. Some use 0-32000 some 0-16000.

[Joan M 3]

You need to know how the PLC you are working with handle 0..10V outputs, typically it will link that analog output to a variable in your PLC. Being a 0..10V the most usual would be to have it linked towards a WORD or a BYTE as you don’t need to go into the negative side of the value. Then, the variable you will have linked the analog output will define which scale you need. If you are using a PID (which would be the best in that case) you will be able to control the output in the best possible way (forget fuzzy logic as it is too hard to cope with) and it works wonderfully and you will save electricity. Good luck!