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PLATINUM

TM

 Series User’s Guide 

47 

Reference Section: Programming Mode (PRoG) 

5.6.1

 

Cascade Control using Remote Setpoint 

The remote Setpoint feature of the PLATINUM

TM

 Series controllers can be used in a variety of 

applications where Setpoints can be sent to the controllers from remote devices such as a manual pots, 
transmitters, computers, etc. This feature can also be used to set up a “cascade control” system, where 
the remote Setpoint input is generated by another controller. Figure 5.3 shows a generic diagram of a 
cascade control system and Figure 5.4 shows a typical example, in this case a heat exchanger 
application. 

 

 

Figure 5.3 Generic Cascade Control Diagram 

Figure 5.4 Heat Exchanger with Cascade Control 

Cascade control schemes can provide tighter control of a process when you have two linked variables, 
one of which has a much slower (typically 4X or more) response than the other. The slower responding 
variable is used as the input to the primary or master controller, and the faster responding variable is 
used as the input to the secondary or slave controller. The output of the primary controller is scaled to 
be used as the Setpoint for the secondary controller. 

In the heat exchanger application in Figure 2, the primary goal of the application is to control the 
temperature of the effluent. Therefore, the desired effluent temperature becomes the Setpoint for the 
primary controller, which is a temperature controller (TC). The process input for the temperature 
controller is the measured temperature of the effluent (TT). The output of the temperature controller is 
the flow Setpoint for the secondary controller, which is a flow controller (FC). The process input for the 
secondary (flow) controller is the flow rate of the steam that is used to heat the process flow through 
the heat exchanger (FT). The output of the secondary (flow) controller is a control signal for the 
proportional valve controlling the flow of the steam. 

By isolating the slowly changing effluent temperature control loop from the rapidly changing flow 
control loop, a more predictable, robust, and tighter control scheme results. 

 

 

Omega Engineering | www.omega.com 

 

Summary of Contents for CN16Pt

Page 1: ...CN32Pt CN16Pt CN16PtD CN8Pt CN8PtD Temperature Process Controllers...

Page 2: ...Introduction The information contained in this document is believed to be correct but OMEGA accepts no liability for any errors it contains and reserves the right to alter specifications without notic...

Page 3: ...2 Programming Mode Menu PRoG 19 3 3 Operating Mode Menu oPER 21 4 Reference Section Initialization Mode INIt 22 4 1 Input Configuration INIt INPt 22 4 1 1 Thermocouple Input Type INIt INPt t C 22 4 1...

Page 4: ...ment INIt t CAL 2 PNt 33 4 6 4 Temperature Ice Point Calibration INIt t CAL ICE P 33 4 7 Save Current Configuration for All Parameters to a File INIt SAVE 33 4 8 Load a Configuration for All Parameter...

Page 5: ...ut PRoG PId A to 44 5 5 3 Autotune PRoG PId AUto 44 5 5 4 PID Gain Settings PRoG PId GAIN 44 5 5 5 Low Output Clamping Limit PRoG PId Lo 45 5 5 6 High Output Clamping Limit PRoG PId HI 45 5 5 7 Adapti...

Page 6: ...6 7 Clear Latched Alarms oPER L RSt 54 6 8 Display Valley Reading oPER VALy 54 6 9 Display Peak Reading oPER PEAk 54 6 10 Standby Mode oPER Stby 54 7 Specifications 55 7 1 Inputs 55 7 2 Control 55 7 3...

Page 7: ...h auxiliary event actions available with each segment Up to 99 Ramp and Soak programs can be stored and multiple Ramp and Soak programs can be chained creating unmatched ramp and soak programming capa...

Page 8: ...ting up the data communications protocol for each of the communications channels configuration for multiple outputs etc This manual is optimized for online use Therefore the blue entries in the Sectio...

Page 9: ...drawn from the main supply in case of a fault in the equipment an overcurrent protection device must be installed Do not exceed the voltage rating on the label located on the top of the instrument ho...

Page 10: ...tor if EIP Option Installed 1 4 Wiring Instructions 1 4 1 Back Panel Connections Figure 1 1 CN8Pt Models Back Panel Connections Figure 1 2 CN16Pt and CN32Pt Models Back Panel Connections Ethernet Comm...

Page 11: ...pin input connector assignments are summarized in Table 1 0 Table 1 1 summarizes the universal input pin assignments for different sensor inputs All sensor selections are firmware controlled see 4 1 I...

Page 12: ...ed for the RtN instead of Pin 1 on the Input Connector Remote Setpoint is not available if you are using an RTD sensor and you have an SPDT Type 3 Output installed Requires external connection to pin...

Page 13: ...Analog current or voltage Table 1 3 Output Type Designations Power Output Pin Number Config Description 8 7 6 5 4 3 2 1 330 SPDT SPDT AC or DC AC or DC N O Com N C N O Com N C 304 SPDT DC pulse N O Co...

Page 14: ...s down a level or it enters a numerical value or parameter choice 2 2 Menu Structure The menu structure of the PLATINUMTM Series is divided into 3 main Level 1 groups which are Initialization Programm...

Page 15: ...le R Type R thermocouple S Type S thermocouple b Type B thermocouple C Type C thermocouple Rtd N wIR 3 wI 3 wire RTD 4 wI 4 wire RTD 2 wI 2 wire RTD A CRV 385 1 385 calibration curve 100 385 5 385 cal...

Page 16: ...ge 0 to 24 mA 10 Process input range 10 to 10 mA 1 Process input range 1 to 1 mA 0 1 Process input range 0 1 to 0 1 mA RdG dEC P FFF F Reading format 999 9 to 999 9 FFFF Reading format 9999 to 9999 FF...

Page 17: ...status bytes RdNG yES Includes process reading No PEAk No yES Includes highest process reading VALy No yES Includes lowest process reading UNIt No yES Send unit with value F C V mV mA _LF_ No yES App...

Page 18: ...plays RUN SP LM SP Lo ____ Low Setpoint limit SP HI ____ High Setpoint limit LPbk dSbL Loop break timeout disabled ENbL ____ Loop break timeout value MM SS o CRk ENbl Open Input circuit detection enab...

Page 19: ...tions from SP2 ALR H ____ Alarm high parameter for trigger calculations ALR L ____ Alarm low parameter for trigger calculations A CLR REd Red display when Alarm is active AMbR Amber display when Alarm...

Page 20: ...olts 0 5 0 5 Volts 0 20 0 20 mA 4 20 4 20 mA 0 24 0 24 mA oUt2 oUt2 is replaced by output type oUt3 oUt3 is replaced by output type PId S ACtN RVRS Increase to SP1 i e heating dRCt Decrease to SP1 i e...

Page 21: ...gment number to edit entry replaces below MRt ____ Time for Ramp number default 10 MRE oFF Ramp events on for this segment oN Ramp events off for this segment MSP ____ Setpoint value for Soak number M...

Page 22: ...ers to a File INIt SAVE 33 4 8 Load a Configuration for All Parameters from a File INIt LoAd 34 4 9 Display Firmware Revision Number INIt VER N 34 4 10 Update Firmware Revision INIt VER U 34 4 11 Rese...

Page 23: ...sed Navigate to the desired configuration parameter N wIR Firmware selection of the number of wires for RTD connection no jumpers needed A CRV Calibration curve covering both the international standar...

Page 24: ...signal input outside of the specified hardware input range will result in an out of range error code E009 Input range choices include the following 4 20 4 mA to 20 mA factory default 0 24 0 mA to 24 m...

Page 25: ...lude the following dEC P Decimal point format entry point F C Temperature units FLtR Filter readings displayed per second ANN 1 Annunciator 1 setting ANN 2 Annunciator 2 setting NCLR Normal color defa...

Page 26: ...desired setting corresponding to the number of readings per displayed value Settings include the following calculated times between display value updates are shown for each setting as well 8 0 4 s fac...

Page 27: ...t the Normal Color NCLR parameter This controls the default display color which can then be overridden by Alarms Navigate to the desired setting Settings include the following GRN Green factory defaul...

Page 28: ...te to the desired parameter submenu Options include the following PRot Protocol AddR Address Note The serial communications SER option above also includes the following parameter C PAR Communications...

Page 29: ...the highest process reading so far o VALy Sends the lowest process reading so far o UNIt Sends the unit with the value F C V mV mA _LF_ Select yES or No yES sends a line feed between each data block...

Page 30: ...of wires Select the indicated option 4 4 3 2 Baud Rate INIt CoMM SER C PAR bAUd Select the Baud Rate bAUd parameter The device being communicated to determines how fast you can set the Baud Rate Navig...

Page 31: ...reak enable disable and timeout value o CRk Open circuit detection enable disable Select the indicated option 4 5 1 Power On Confirmation INIt SFty PwoN Select Power On Confirmation PwoN Navigate to t...

Page 32: ...elect the open circuit o CRk parameter When o CRk is enabled the unit will monitor Thermocouples RTD and Thermistors for an open circuit condition Navigate to the desired setting Settings include the...

Page 33: ...ir it with the current input reading 4 6 4 Temperature Ice Point Calibration INIt t CAL ICE P Select ICE P to calibrate the zero point for the temperature sensor This function basically operates the s...

Page 34: ...number and 4 is the bug fix update number 4 10 Update Firmware Revision INIt VER U Select the Update Firmware Revision VER U function Note that updating your firmware will reset the unit to factory d...

Page 35: ...t Channel 1 4 Configuration PRoG oUt 1 oUt 4 40 5 5 PID Configuration PRoG PId 43 5 6 Remote Setpoint Configuration PRoG RM SP 46 5 7 Multi Ramp Soak Mode Parameters PRoG M RMP 48 5 1 Setpoint 1 Confi...

Page 36: ...ss the condition persists default 1 0 s dE oF Time delay for cancelling Alarms after being triggered prevents Alarm chatter default 0 0 s Select the indicated setting 5 3 1 Alarm Type PRoG ALM 1 ALM 2...

Page 37: ...s triggered using calculations based on the absolute values of ALR H or ALR L used as specified by the tyPE parameter d SP1 Alarm is triggered using calculations based on values relative to SP1 as spe...

Page 38: ...lude the following oFF High High Low Low function disabled factory default oN Display will flash in the color determined by the A CLR parameter when the Process Value is greater than the HI HI offset...

Page 39: ...tion Option include yES Alarms are active at power on and do not require crossing the Setpoint factory default No Alarms are inactive at power on the process reading must cross the Alarm condition bef...

Page 40: ...t being configured appear in that output s menu Select the indicated output channel Navigate to the desired submenu Submenus include the following ModE Allows the output to be set up as a control Alar...

Page 41: ...control dEAd Sets the deadband value the deadband value is applied in the same units as the process variable to one side of Setpoint as determined by the ActN direction S PNt Allows either Setpoint 1...

Page 42: ...orresponds to the process value Rd1 Rd2 Process reading 2 the process reading that corresponds to the output signal oUt2 oUt2 The output signal that corresponds to the process value Rd2 Select the ind...

Page 43: ...4 1 2 PID Control Mode PRoG oUt1 oUt4 ModE PId PID control can be optimized in a variety of ways The suggested way is to initiate an autotune command 5 5 3 Autotune PRoG PId S AUto and then enable ada...

Page 44: ...PId GAIN Select Gain GAIN to manually adjust the PID factors You can then manually set the parameters for control Setting I to zero sets the controller for PD control setting d to zero sets the contro...

Page 45: ...down the response of the system even faster than an increase in the Integral Factor will The default value is 00 00 as only quickly responding systems actually need to use the derivative term This fa...

Page 46: ...ck of proximity etc It can also be used to configure the controller in a cascaded control scheme Settings include the following oFF Do not use a remote Setpoint factory default oN Remote Setpoint repl...

Page 47: ...controller and the faster responding variable is used as the input to the secondary or slave controller The output of the primary controller is scaled to be used as the Setpoint for the secondary cont...

Page 48: ...rmation on this For an overview of Ramp and Soak programming including examples see Section 5 7 8 Note When setting up multidirectional ramp and soak programs only one direction can use PID control as...

Page 49: ...mp Time the unit will continue to ramp until that setpoint is reached The additional ramp time required is subtracted from the soak time so that the specified cycle time ramp time soak time is preserv...

Page 50: ...ou view it on the unit s display This will help you keep track of where you are when programming multiple ramp and soak segments from the front panel Confirm the segment number Navigate to the desired...

Page 51: ...to link multiple profiles together to implement extended sequences Although the term RAMP is used to indicate the process variable change there is no restrictions on the direction of change The Target...

Page 52: ...6 1 Normal Run Mode oPER RUN 52 6 2 Change Setpoint 1 oPER SP1 53 6 3 Change Setpoint 2 oPER SP2 53 6 4 Manual Mode oPER MANL 53 6 5 Pause Mode oPER PAUS 53 6 6 Stop Process oPER StoP 54 6 7 Clear La...

Page 53: ...et the desired value for Setpoint 2 Confirm the value 6 4 Manual Mode oPER MANL Select the Manual Operating Mode MANL This mode allows for control output levels or the process input value to be manual...

Page 54: ...Valley Reading VALy to change the process value displayed to the lowest reading since VALy was last cleared Clear the VALy reading buffer Return to RUN Mode or to displaying RUN depending on the Opera...

Page 55: ...Conversion 24 bit Sigma Delta Reading Rate 20 samples per second Digital Filter Programmable from 0 05 seconds filter 1 to 6 4 seconds filter 128 CMRR 120 dB Excitation Firmware selectable no jumpers...

Page 56: ...rotocols Omega ASCII Modbus ASCII RTU 7 5 Isolation Approvals UL C UL and CE 8 Approvals Information Power to Input Output 2300 Vac per 1 min test 1500 Vac per 1 min test Low Voltage Power Option Powe...

Page 57: ...Models 5 W power for 8DPt 16DPt Models Low Voltage Power Option External power source must meet Safety Agency Approvals Units can be powered safely with 24 Vac power but no certification for CE UL is...

Page 58: ...7 F RTD Pt 0 00385 100 500 1000 200 to 850 C 328 to 1562 F 0 3 C 0 5 F RTD Pt 0 003916 100 200 to 660 C 328 to 1220 F 0 3 C 0 5 F RTD Pt 0 00392 100 200 to 660 C 328 to 1220 F 0 3 C 0 5 F Thermistor 2...

Page 59: ...gory I includes measurements performed on circuits not directly connected to the Mains Supply power Maximum Line to Neutral working voltage is 50Vac dc This unit should not be used in Measurement Cate...

Page 60: ...Omega Engineering www omega com...

Page 61: ...M5451 0415 Omega Engineering www omega com...

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