SRC Heating Control

What temperature can you get up to if you wire the heater directly to the supply?

it reaches upto 360 and can go further we tried upto 380

Does the controller indicate 328°C? Does an independent measurement also give 328°C? If both of these are true, it suggests that the controller is not correctly receiving the setpoint value from the PLC.

yes both and actual and plc reading are matching .

also we simulate from feildd and both the readings are matching.

Does it reach 340°C if you change the PLC setpoint to, say, 352°C?

we cant change the set value as it is computed value from PLC but if we take in auto mode also it has no change because the output reaches to 20 ma ie 100% with computed value also in auto mode

Sorry, I've just about run out of ideas of things to try remotely.

what we analyse is the SRC which is triggerring the heater can you tell me about it necessary configuration so as to get full output

Do you have any details of it? Manufacturer & type number, for example?

Depending on the size of the heating load there can be transients occuring during commutation within the SCR. A simple R/C filter of sufficient size may be all that is needed to filter the transients and protect the SCR.

I would suggest connecting the element directly to line and amping it. Read volts, calculate watts. Reconnect to SCR and provide a full with a signal generator , verify signal 20ma. Element should be full on no duty cycle. Again amp element and read volts. Watts should be very close to line readings. If not replace SCR controller. Also verify signal from PLC controller. If full signal is not at 20ma SCR is still modulating.