Sigma C4 manual 108

Page 108

Proportional term

Setup parameter

F0

Integral term

Setup parameter

F10

Differential term

Setup parameter

F11

Note that you will also find the in setup section of this manual a reference to the Integral Wind-up Limiter Term (Setup parameter F12). Do not alter this field. It is set once at the factory for the C4 model controller and never requires adjustment.

Adjusting for changing needs.

When you C4 was shipped from the factory, it was optimized, or “tuned”, for normal operation of the chamber or platform to which it was attached, or for which it was intended. It was presumed that the load that you would test would not have great mass, that some overshoot of the setpoint was acceptable when going to a new temperature, and that the cryogenic coolant available (if used) would be delivered from a supply source that indeed delivered liquid, not just compressed gas.

Your needs may not match the original settings, or your controller may have had it’s settings changed for other reasons. If the controller is settling a little short of the setpoint, or is oscillating, you can probably make a few changes in the PID settings and improve things considerably.

You need to be aware that very precise control requires a stable environment. The C4 is an excellent and accurate controller. However, it is not magic. For example, if you tune your C4 to provide fast ramps with conservative approaches to setpoints with liquid nitrogen cooling a static load, and then run the unit using a nitrogen source that delivers gas instead of liquid a good part of the time, and then you add a substantial live load as well, your system performance will not be what you expected. Before you start the tuning process, we suggest that you do what you can to be sure that you are tuning for the actual loads that you will be testing using the coolant that will be available at test time.

If you are using cryogenic coolant, be certain that the coolant delivery is consistent. It is not possible to provide a stable environment in your chamber or on your platform if the supplied coolant’s ability to absorb heat keeps drastically changing as the supply vacillates between liquid and gas. Likewise, if you will have live loads that turn on and off during the test, optimize the performance of the system with the load at the point that is most critical to you. If the live loading is small, it should make little difference. However, if the live load is substantial, the performance of the system will be adversely affected when it is operating with a load substantially different than the load for which it was tuned.

108

C4 Manual Rev 7.5.2

Page 107 Page 109
Image 108
Page 107 Page 109
Contents Programmable Temperature Controller / Interface Sigma SystemsC4 Manual Rev Table of Contents Intelligent 2 Probe Control C4 Manual Rev C4 Manual Rev C4 Manual Rev C4 Manual Rev Introduction Models C4 & CC-3.5ExplainedGeneral Description Custom Features / Interchangeability Warning Release 7.5.2 FirmwareC4 vs. CC-3 Differences What’s New Firmware Uploads Forced Start from Prom Firmware Internal Error Shutdown Conditions Intelligent 2 Probe Control Probe Averaging Program Mode Step Insert & Delete RSA Remote Mode Setup Parameter Commands Physical Description Front PanelMode Switch Clear Prog Rear Panel Connections J1 TOPGeneral Operation & Error Conditions C3-5 Rel200 100c 392 148f Startup DisplaysUpdating Firmware Upgrading Firmware by Prom Replacement Making the physical connection for upload Restoring Setup Parameters to Default Values Rs loadSu res Ee busy and then su doneC4 Manual Rev P1f Fahrenheit OperationSystem Operating Temperature Range P1 lo P1 hiProbe Out of Range Shutdown P1 err P1 -err Internal Error Shutdown Conditions Res errAll res Su err Software Probe Correction CalibrationStatus and Error Reporting Fail-safe System C4 Manual Rev Intelligent 2 Probe Control How Intelligent 2 Probe Control functions Preparing for Intelligent 2 Probe Control Using Intelligent 2 Probe Control Local Mode Basic Operation Displaying TemperatureS1 102.6 s1f S1 nsp S1f nspDisplaying and Changing the Setpoint Sor -sor Sp errControlling to a Setpoint C4 Manual Rev Program Mode 06.0Description of a Program Step Substep Step Data 00.0 00.1Ramp time 00.2Maximizing Ramp Speed & Other Ramp Considerations Clearing Program Memory Reinitializing program steps Displaying Program Steps not during executionEntering or Changing a Program Step Insert Program StepPress CLEAR/ENTRY Delete Program step Press CLEAR/ENTRY Press CLEAR/ENTRY againRunning Executing a Program Program Run Time Information/Considerations 007 nop2 Loop005 sor Sor Special Commands External Compressor On Common Programming Issues C4 Manual Rev Remote Mode EIA-232 InterfaceIEEE-488 Interface Command Summary by functional group System Information QueriesSystem Information Queries For Celsius mode For parameters numbered 0 through C4 Manual Rev Operation Information Queries & Commands REerror byteCRLF C4 Manual Rev Qccrlf PTnCRLF Setup Parameter Commands SC1 0 2.3 100 WP 6 5 5CRLF Upcrlf System Operation Commands Celsius mode Will hold the current setpoint for 1 hour and 20 minutes U1c 65.0 u1f Error and Status Reporting Overview IEEE-488 GpibTemperature in 20 minutes C4 Manual Rev Error/Status String Bit Definitions C4 Manual Rev Setup Mode PID controller, Integral term Adjustment not Displaying the Field Values Changing the Value of a Setup Field Two Probe Mode Setup fieldAuto-start Mode Setup field Blower Shut-off Mode Setup field Temperature Control Terms PID Setup fields 0, 10, 11Entering probe correction setup data C4 Manual Rev C4 Manual Rev Appendix Programming Examples & Notes00.0 00.200.3 00.4Using shortcuts to shorten program entry time 9900 DISP/CNTLSTART/STOPCLEAR/ENTRY 6 Enter 04.0 04.204.3 04.407.0 07.207.3 07.4C4 Manual Rev Sigma Systems C4 Programming Worksheet Sample Command Structure for IEEE-488 Gpib Operation Disp A$ Installation and Use of TTL Outputs and Input Field Calibration of Model C4 Controller 101102 Troubleshooting 103Noise Immunity 105 Firmware Upload Problems Temperature Control PID Tuning & Problems 107108 109 110 111 U1f 102.7 Technical Support, Repairs & ReturnsIndex 113114 Gpib 115IEEE488 Gpib 117 118 SRQ 119120
Top Page Image Contents