In the copper wire drawing line, the 16-wire annealing unit uses direct electrical resistance heating to soften the wires after the drawing process. The machine operates at speeds of up to approximately 10 m/s, so the control system must continuously adjust the annealing power level according to the wire speed.
In this project, the existing Siemens SIMOREG controller is replaced by a Parker DC598P External Stack Controller, while the existing transformer and power SCR stack are retained.
1. Operating Principle of the 16-Wire Annealing System
The 380 VAC power supply is fed through a step-down transformer and then supplied to the power SCR stack.
Basic operating principle:
380 VAC → Transformer → SCR → DC+ / DC− → Annealing Wheels → 16 Copper Wires
The controller does not directly supply power to the copper wires. Instead, it controls the SCR firing angle. By generating appropriate firing pulses, the SCR regulates the DC voltage and current supplied to the annealing wheels.
The DC+ and DC− levels are adjusted according to the annealing process requirements and must be coordinated with the wire running speed to ensure stable and consistent heating conditions.
2. Siemens SIMOREG SCR Control
In the existing system, the Siemens SIMOREG is responsible for controlling the SCR power stack and communicating with the Siemens S7-300 PLC via PROFIBUS.
The PLC sends the following control-related data to the SIMOREG:
- Operating commands.
- Speed reference.
- Annealing setpoint.
- Calibration coefficients.
- Process parameters.
The SIMOREG processes these values and generates SCR firing pulses to produce the appropriate voltage and current levels for the annealing unit.
In the reverse direction, the SIMOREG sends data such as status, voltage, current, and actual values back to the PLC for processing and display on the HMI.
3. Replacing Siemens SIMOREG with Parker DC598P
During the system upgrade, the Parker DC598P External Stack Controller is used to replace the existing SIMOREG.
The DC598P is designed to operate with an external power SCR stack, providing thyristor firing signals and receiving feedback signals from the power stack.
Therefore, the upgrade does not require replacing the entire power section of the machine. Instead, it focuses on replacing the SCR controller:
SIMOREG → Parker DC598P
Meanwhile, the existing power structure:
Transformer → Power SCR Stack → Annealing Wheels → 16 Copper Wires
is retained after inspection and necessary adjustments.
4. Parker DC598P Communication with the S7-300 PLC via PROFIBUS
One of the key requirements of the project is to continue using the existing Siemens S7-300 PLC and PROFIBUS network.
After replacing the DC598P, the required data exchange between the controller and the PLC was reconfigured to meet the machine’s operating requirements.
PLC → Parker DC598P
- Control commands.
- Speed reference.
- Annealing setpoint.
- Calibration parameters.
- Process parameters.
- Reset commands and other required control signals.
Parker DC598P → PLC
- Status.
- Ready/Run status.
- Fault/Alarm status.
- DC voltage.
- DC current.
- Actual values.
- Monitoring parameters.
The conversion was not simply a matter of changing data addresses. The meaning of each signal had to be correctly remapped between the new controller and the existing PLC program.
5. Maintaining HMI Parameters
After replacing the controller, the required parameters continue to be transferred to the S7-300 PLC, allowing the HMI to maintain its existing monitoring functions.
The operator can monitor parameters such as:
- Machine speed.
- Annealing setpoint.
- Annealing current.
- Annealing voltage.
- Actual values.
- System status.
- Alarms and faults.
- Required calibration parameters.
As a result, replacing the controller does not change the machine’s main operating structure.
6. Results After the Upgrade
After completion of the upgrade, the Siemens SIMOREG was replaced by the Parker DC598P to control the SCR power stack of the 16-wire copper annealing system.
The upgraded solution retains:
- The existing step-down transformer.
- The existing power SCR stack.
- Siemens S7-300 PLC.
- PROFIBUS communication.
- Required control signals.
- Feedback data.
- Monitoring parameters on the HMI.
The Parker DC598P is responsible for SCR firing control, allowing the DC+ and DC− levels supplied to the annealing wheels to be adjusted according to the annealing process requirements and machine speed.
This is a control-system-focused upgrade solution, suitable for copper wire annealing systems that use older-generation SCR controllers while the existing power section and machine structure remain suitable for continued operation.
