Series 920 Microprocessor-Based Ramping Control User’s Manual Watlow Controls, 1241 Bundy Blvd., Winona, MN 55987, Phone: 507/454-5300, Fax: 507-452-4507 W920-MA60-9302 January, 1993 Supersedes: W920-MC5A-8944 $10.00 Made in the U.S.A.
First... This manual will make your job easier. Reading it and applying the information is a good way to become familiar with the Series 920. Here’s an overview: Starting Out Introduction, Chapter 1. Front Panel Keys and Displays, Chapter 2. Running a Program Sample Program, Chapter 3. lnstall/Wire Installation and Wiring, Chapter 4. Tune How to Tune, Chapter 5. Programming How to Program, Chapter 6. Alarms How to Use Alarms, Chapter 7.
Page Item 6 6 7 7 8 8 9 10 10 Starting out with the Watlow Series 920 - Chapter 1 General Description Packing List Put Your Control to Work-Three Steps How to Open the 920 How to Set the DIP Switches Changing the Position of a DIP Switch Overview of the Three Operating Modes Where To Go From Here 11 11 11 12 13 13 14 How to Use the Keys and Displays - Chapter 2 Display, Key and LED-Location and Explanation Front Panel Information Actual and Alphanumeric Display Area Keyboard Area Where To Go From Here
Tuning Programming Alarms Appendix Terminology Quick Reference Page Item 33 33 33 33 34 35 35 How to Tune the Series 920 - Chapter 5 Recommended Tuning Reference Using a Chart Recorder Load LEDs Tuning The LOPWR and HIPWR Parameters Where To Go From Here 36 36 36 36 37 37 38 39 40 42 49 HOW to Program the Series 920 - Chapter 6 Write Out Your Program Programming in General Select the Proper DIP Switch Settings Event Ouputs Guaranteed Soak The Four JUMPLOOP Types Rules to Follow SYSTEM Menu SETUP
Figures, Tables and Charts .
Chapter 1 Starting out with the Watlow Series 920: A Microprocessor-Based Control Dual PID FF or ON/OFF outputs Selectab RTD, T/C Process Figure lSeries 920 Input and output Overview or Two Auxiliary Outputs RS-422A or RS-423A (RS-232C Compatible) Optional Computer Interface General Description Congratulations, you’re about to become a fully-qualified user of the Watlow Series 920! This versatile microprocessor-based ramping control is powerful, yet simple to learn.
The Series 920 is a PID controller. You may input two complete sets of PID parameters on the front panel for heat/cool applications. This includes rate, reset, proportional band and cycle time. By setting the proportional band(s) to zero, the Series 920 becomes a simple ON/OFFcontrol with a 3°F or 1.7°C switching differential. The 920s auxiliary outputs may be alarms or events. An event is an ON/OFF auxiliary output relay signal.
How to Open the 920 Before going further, open the Series 920 and pull the control chassis from its case. Here’s how: The control chassis fastens to the case with a single screw located on the lower front panel. See Figure 2. Turn the screw counterclockwise to loosen it. Three or four strip connector plugs, in the rear of the control chassis, feed power and signals through the back of the casing to the triple terminal strip. These plugs will let go as you pull.
Figure 3 DIP Switch Location and Orientation.
Overview of the Three Operating Modes Before getting into the details of the Series 920s keys and displays, take a look at Figure 4 showing the three different modes. After you feel comfortable with the names of the modes and their functions, go ahead to learn the keys and displays.
Chapter 2 How to Use the Keys and Displays This chapter will show you the Series 920 front panel, and the function of each display, key and LED. Figures 6 and 7 explain the 920 front panel. Display, Key and LED-Location and Explanation The Watlow Series 920 Ramping Control has two main displays, the process ACTUAL display at the top of the unit, and the smaller alphanumeric display below. You set up the Series 920s characteristics in the alphanumeric display window.
Use the following figures to learn the nature and function of the Series 920s keys and displays. Figure 5 Series 920 Front Panel Information. Actual and Alphanumeric Display Area °F LED When DIP switch #6 is OFF, it indicates the value in the ACTUAL display is temperature in degrees Fahrenheit. When DIP switch #6 is ON, it indicates Output 1 is energized. ACTUAL Display X, Shows the actual value of the process variable up to four digits. Figure 6 Actual and Alphanumeric Display Front Panel lnformation.
Keyboard Area MODE Key This key steps the Series 920 in sequence Figure 7 Keyboard Front Panel Information. DOWN Key Acts opposite the UP key. Decreases the value in the alphanumeric display. A light touch decreases the value by one digit. Hold the key down to decrease the displayed value at a rapid rate. RUN/HOLD Key Executes or holds a program from the SYSTEM menu. Run/Hold LEDs Increases the value in the alphanumeric display. A light touch increases the value by one digit.
Chapter 3 Learning the Series 920 A Sample Program in Action This chapter will guide you through an easy sample program for the Series 920. You can quickly grasp the necessary terms and concepts by entering andobserving this exercise. If you feel that your knowledge of profiling controllers does not require a sample program to learn the Series 920, skip this chapter.
2 4. Use the UP/DOWN keys to place hours into the display. The display will flash until you press ENTER. J 5. Press MODE to continue to the MIN parameter and press ENTER. Enter the correct value for minutes and press ENTER. 6. Press the MODE key several times to return to the top of the ACCESS (0) menu. At the top of the ACCESS (0), which is the CALIB menu, you will see the Real Time (Tl) displayed. 7. Continue to press MODE until you reach RETURN. Press ENTER to return to SYSTEM.
4. Press the MODE key. Use the UP/DOWN keys to select the step type and values. 5. Use Table 2 to enter the corresponding parameters and values. The parameters appear from left to right on the table. Remember that the MODE key is used to progress through the menus. After the step # is selected, use the UP/DOWN keys to select a step type. Press ENTER. Use the UP/DOWN keys to select parameters and values, they remain flashing until you press the ENTER key.
Editing Your Program Let’s try editing the program by expanding it with another ramp and soakstep and adding a jump loop. We’ll jump to Step 1 and repeat Steps 1 - 6 two more times. This is accomplished by programming a Jump Step (JS)= 1 and Jump Count (JC) = 2. When your 920 goes through the program and reaches Step 6, it jumps back to Step 1 and repeats the program two more times. By this time you should understand the basic concept of the Series 920 and be able to get around on your own.
LlNKing Files The Series 920 enables you to link files together. The LINK step allows you to link the last step of a profile to the first step of another profile. Lets edit the program again by adding a LINK step at the end of the profile. But first, lets create another file. If you run your program with a LINK going to a non-existing file, you’ll receive ER2 0036, the “no file found“ error. Follow Table 5 to add a LINK and a new FILE to your program. Table 5 LlNKing to Another File.
WAITFOR Process Variable (WPV). When equal, the HOLD LED stops flashing. Your program then continues to the last step, a STOP step, and HOLD S again. To change a programmed step, return to the PROGRAM menu, and enter the FILE and STEP number to change. Use the UP/DOWN keys to select another step type and press ENTER. Under a step type, to clear all parameters of the current values, return to that step type and press ENTER. All parameters will return to their defaults.
Chapter 4 How to Install and Wire the Series 920 This chapter tells you how to install the Series 920. All mounting and wiring information is right here. Because Watlow controls are thoroughly tested, and “burned in” before leaving the factory, the Series 920 is ready to install when you receive it. But before you begin working or cutting holes in panels, read through this chapter to gain an understanding of the entire installation. Consider sensor installation carefully.
Definitions Ground Loop - A condition created when two or more paths for electricity are created in a ground line, or when one or more paths are created in a shield. Earth Ground - The starting point for safety and computer grounds. It is usually a copper rod driven into the earth. Safety Ground - A ground line run with electrical power wiring to protect personnel. Computer Ground - A ground line for the ground connections to computers or microprocessor-based systems.
How to Check for Ground Loops To check for ground loops, disconnect the ground wire at the ground termination. Measure the resistance from the wire to the point where it was connectedThe ohmmeter should read a high ohm value.If you have a low ohm value across this gap, that means there is at least one ground loop present in your system. Also, check for continuity; your reading should be “open”. If you do find continuity, you must now begin looking for the ground loops.
Keep filters 12 inches (304.8mm) or less from the control. Minimize the line distance where noise can be w-introduced to the control. J 1 Ll D.M. Line Filter Control L2 Figure 9 Differential Mode Filter Diagram. Ground Ll L2 Ground C.M. Line Filter Line Control Load Figure I0 Common Mode Filter Diagram. To prevent ground loops, do not fasten common mode line filters or filters with metal cases to metal that is at ground potential. Doing so will reduce filter effectiveness. D.M. Line Filter C.
Installation Information The Series 920 mounts in a panel cutout with two brackets. These brackets hold the case against the front panel. The Series 920 behind-panel dimensions are 3.56 in. (90.42mm) high by 3.56 in. (90.42mm) wide by 6.0 in. (152.4mm) deep. If your unit has a triac output, add another 2.5 in (63.5mm) to the depth. Figure 12 shows the dimensions of the front panel bezel. The 920 weighs 2.75 lbs. (1.25Kg).
(23.37mm) t 1 &-Bezel 3.56 ±0.015 (90.42mm 3 ±0.381 3.81 (96.77mm) Mounting Bracket Figure 13 Series 920 Dimensions. (side view) 3.622 to 3.653 (92.00 to 92.79mm) Your Panel Thickness Panel cutout 0.06 to 0.25 (1.524 to 6.35mm) 3.625 x 3.625 (92.08 x 92.08mm) Nominal Figure 14 Series 920 Panel Cutout Dimensions. 3.622 to 3.653 (92.00 to 92.79mm) I How to Wire the Series 920 This section has all the information you need to complete a good wiring job on the Series 920 and your system.
0 Power Wiring 1 WARNING: To avoid potential electric shock, use National Electric Code safety practices when wiring and connecting this unit to a power source and to electrical sensors or 01 2 WARNING: To avoid electric shock, connect the chassis ground terminal to “Earth NOTE: For 115VAC, jumper 17 to 19 and jumper l8 to 20 For 230VAC, jumper 18 to 19 Chassis A 0; J3 1 NOTE: peripheral devices. 0 @2 Ll GND 17 Ll 18 19 Ground.” Green GND k Wire Figure 15 Series 920 Power Wiring.
Input Options: Terminals 1- 8 Apply One Input Only 1 RTD k For a two-wire RTD, use Terminals 1 and 2 for the RTD, and jumper Terminal 2 to Terminal 3. l For RTD input, use Terminals 1,2 and 3. Figure 16 input Options Wiring Diagram. For 0-5VDC, 0-20mA or 1-5VDC, 4-20mA input, use Terminals 4 and 5. l See model number information, p. 61, for the input option that applies to your unit. l For T/C input, use Terminals 6 and 8. T.C.
Output #1 Option B, Terminals 22 - 24 Figure 18 Output 1, S.S. Relay, Option "B", Wiring Model#92OA-_ B _ _-_000 Diagram. m , m output #1 to Im Load from S.S. Relay, 0.5A I i ! S.S. I m k I 23 N.O. (MT2) Figure 19 - Output #1 Option C, Terminals 22 - 24 S.S. Switch, Option "C", Model #92OA-_ Output 1 C _ _-_000 Wiring Diagram Output #1 to Load from S.S. Switch, 20mA 22 Switched DC (open collector) 23 + Unreg. (20VDC @ 20mA max.
Output #1 Option D, Terminals 22 - 24 Model #92OA-_ D_ _-_000 Figure 20 Output 1 Mech. Relay, Option "D", Wiring Diagram. Output #1 to ;~~~~~~~~~~~~_~_~_______, I i Mechanical : : Relay : II :t : I: I I.1 : l+ : : Load from 6A SPDT Relay A /?\ m n T CAUTION: If you use normally closed contacts of L l the mechanical relay, you may need to add an external snubber (Watlow Part # 0804-01470000) across the normally closed contacts to avoid RF 0 L2 noise and potential malfunction.
Output, #l Option F, Terminals 22 - 24 1 NOTE: Current for the 4-20mA loop is sourced internal to the control. Model #920A-_ F _ _-_000 Output #1 to Load from 4-20mA source Use ungrounded sensors only. mA Figure 22 output 1,4-20mA Option "F", Wiring Diagram. 1 24 Output #2 Option A, Terminals 14 - 16 Model #92OA- - - A_-_000 Figure 23 No Output 2. 14 Not Used 16 Not Used Output # 2 Option B, Terminals 14 - 16 Figure 24 output 2 S.S. Relay, Option "B", Wiring Diagram.
Output #2 Option C, Terminals 14 - 16 Figure 2 5 Output 2 S.S. Switch, Option "C", Wiring Diagram. Model #920A- _ _ C - _ 000 Output #2 to Load from S.S. Switch, 20mA 14 Switched DC (optn collector 15+ Unreg. (20VDC @ 20mA max. - switched + 3-32VDC Input a 3 to 32VDC input n? CAUTION: If you use normally closed contacts of the mechanical relay, you may need to add an external snubber (Watlow Part # 0804-01479 0000) across the normally closed contacts to avoid RF noise and potential malfunction.
System Wiring Example Figure 27 System Wiring Example. This example shows a typical Series 920 wiring scheme. it represents only one of many output configurations.
Chapter 5 How to Tune the Series 920 This chapter will explain tuning the Series 920 to the system it controls. Recommended Tuning Reference There are a number of quality references on the art of tuning electronic controllers to the systems they control. If you are not an instrument technician qualified to tune thermal systems, we suggest that you obtain and become familiar with the reference below before attempting to tune your system.
Tuning For optimum control performance, tune the 920 to a thermal system. The tuning settings here are meant for a broad spectrum of applications; your system may have somewhat different requirements. Refer to the key flow charts and diagrams and definitions on Pages 41,45 - 47 for prompt location and description. J NOTE: When tuning in the Heat mode, use PID prompts followed by H. Set the set point above ambient. When tuning in the Cool mode, use PID prompts followed by C.
30°F, or 11° to 17°C. Observe the system’s approach to SP. If the load temperature overshoots SP, increase RT to 2.00 minutes. Then raise SP by 20 to 30°F, or 11 to 17°C and watch the approach to the new set point. If RT is advanced too far, approach to the set point will be very sluggish. Repeat as necessary until the system rises to the new set point without overshooting or approaching the set point too slowly. 6.
Chapter 6 How To Program The Series 920 This chapter will enable you to set up the Series 920 quickly and easily. It will explain why it’s a good idea to write out your parameter values. Chapter 6 also shows you flow diagrams of the programming process. Write Out Your Program The Watlow Series 920 controls temperature for a specific heating and/or cooling process. Your setup parameter values, when they’re entered, give the Series 920 orders for the work you want it to perform.
Event Outputs Another feature of the Series 920 is its capability for two event outputs. An “event output” is simply a pre-programmed ON/OFF event per program step. The event may turn any number of peripheral devices ON or OFF to assist you in controlling your process, system or environment. For instance, in an environmental chamber, you might wish to circulate air at a given time in your program for one or more steps.
The Four JUMPLOOP Types The Series 920 gives you the capability to perform four basicjumploop types in your programming. The backward jump, foward jump, nested loops, and intertwining loops. These are only definitions of the four loops. The Series 920 has very few rules concerning loops in your program. Backward Jump The Backward jump is the most common jump. A backward jump will force you to a step already performed. The Jump Step (JS) must be less than the current step.
Nested LOOP A “Nested” loop is a jump loop within a loop. You will be forced to a step either forwards or backwards from your present location. When nested loops are performed, they cannot break across other loops. Your JC can be from 0 - 100 with 0 being an infinite looping.
The next pages will show you each of the Series 920 menus and their prompts and values. Each section, SYSTEM, SETUP, and PROGRAM, has a menu graphic with a table of values, followed by prompt definitions. Don’t write in the tables and charts here, but make copies to document your control. Prompt definitions are also listed in the glossary. SYSTEM Menu The SYSTEM mode shows the status of the SYSTEM set point, event outputs, and error prompts for clearing errors.
Table 8 SYSTEM Prompts and Description. CLR ALARM Make photocopies, keeD original clean: Displays the current alarm. Press the ENTER key to returnto RETURN 1-2 SYSTEM prompt Press the MODE key to return to the SP prompt. One of three main level operating menus. From the SYSTEM menu, you can generate a non- ramp set point (fixed), manipulate Events 1 and 2 ON or OFF, clear system errors, and clear latching .alarms. Represents the current set point.
SETUP Menu While in the HOLD mode, press the MODE key until you see SETUP, press ENTER. These parameters are to setup the personality of your Series 920. Using the MODE to progress through the prompts, use the UP/DOWN keys to select parameters and values and press ENTER. Select each ACCESS number. Follow that parameter sequence to enter values. You must return to SYSTEM before you can continue to the next ACCESS number.
Prompt Description Range AXH J Process Default Deviation Default & High Slew Limit ! 1 382°F/750°C 999°F/555°C/U 0 0 0 0-23 hours 0-59 minutes -90 to 90°F, -50 to 50°C J See Below. See Below. See Below. Range Your Settings Default Range ACCESS = (0) CALIB To enter CALIB parameters, use ACCESS (0) and ENTER. Tl XX:XX Read only. Displays the Real Time. HOUR Enter the hours to display the system time-of-day clock. MIN Enter the minutes to display the svstem time-of-day clock.
1 NOTE: Changing these parameter valueswill default other parameters and clear all programmed files. See Page 47 for details. LOCK CLR FlLE RETURN Enter the Front panel Lock code. 0-2 Press ENTER to display FILE?. Enter a file number to dear. 1 - 10 Press the ENTER key to return to the SYSTEM prompt. Press the MODE key to return to the SPCLFUNC prompt.
One of three main level operating menus. From the SETUP menu, you can setup or change system-operating parameters such as real time, high/low range, alarm types, alarm points, PID settings and communications. You must select each ACCESS number to create the personality of your Series 920. 1 ACCESS (0) 1 ACCESS number (0) must be selected to enter the personality of your Series 920 into the CALIB parameters.
The heating cycle time usually expressed in seconds for a controller to complete one ON/ OFF cycle. Time between successive turn ons. This parameter will not appear if: OUT = CL, or PB H =0 or if your Series 920 has a 4-2OmA output and OUT = HT or HT/CL. Range: 1 to 60 seconds Default: 5 A thermal control band for heating, that defines where the rate (derivative) function begins. This band is in multiples of the heat proportional band. This parameter will not appear if OUT=CL, or PB H=0.
From RETURN, you can go back to the SYSTEM prompt by pressing the ENTER key, or return to ACCESS (3) menu by pressing the MODE key. In the SETUP menu, ACCESS (5) must be selected to enter the SPCLFUNC parameters. When ACCESS (5) is selected under the SETUP mode of the Series 920, the Special Function parameters appear. Here you can select the input type, degrees, output type, auxiliary, and alarm types among others. Selects the type of sensor used as an input to the Series 920.
Determines whether the alarm type for Auxiliary Output 1 will be a process alarm or a deviation alarm for the Series 920. This parameter will not appear if AUX1 = AL, or DIP switch # 7 is ON. Range: Alpha Display Alarm Type Default: P ALTYP1 P Process Alarm ALTYP1 D Deviation Alarm Determines whether the alarm type for Auxiliary Output 2 will be a process alarm or deviation alarm. This parameter will not appear if AUX2 =AL, or DIP switch #7 is ON.
PROGRAM Menu From the Program menu, you can create your files. There can be up to ten profiles; consisting of a total of 99 steps. You can only choose one step type per step. Figure 31 PROGRAM Key Flow Graphics Key @I J = MODE Key NOTE: Shaded parameters may not appear on your control. These parameters are dependent on how your control is configured. See Pages 5 0 - 52 for more lnformation. 83 = ENTER Key aa = UP/DOWN Key At the SYSTEM prompt, press @ to continue to PROGRAM mode.
1 NOTES: The Series 920 leaves the factory programmed for a warm start. STOP steps appear as a defautt until you program your 920. Table 10 PROGRAM Prompts and Description. Make photocopies, keep original clean. PROGRAM Prompt 1 Description FILE? STEP EV1 Ev2 RETURN Range 1 Enter the Event Output 1 status. Enter the Event Output 2 status. Press the ENTER key to return to the SYSTEM prompt. 1 Press the MODE key to return to the STEP prompt.
One of three main level operating menus. From the PROGRAM menu, you can enter or view step type, program loops, wait for conditions, set points, auxiliary (event) outputs ON/OFF, and step duration. Represents the current SYSTEM file of the Series 920 to be edited or reviewed. Range: 1 to 10 files Default: 1 Represents the current step of a file of the Series 920 to be edited or reviewed. Range: 1 to 99 steps Default: 1 One of six step types under the PROGRAM menu of the Series 920.
The number of times that the Series 920 will jump to the step that was specified by the JS step. 0 - Infinite number of jumps. Range: 0 to 100 Default: 0 From RETURN, you can go back to the SYSTEM prompt by pressing the ENTER key, or return to FILE? by pressing the MODE key. One of six step types under the PROGRAM menu of the Series 920 that can be programmed to wait for a specific amount of time, or for a desired set point.
Chart I- Master Step Chart Step # Make photocopies, keep original clean.
Chapter 7 How To Use the Series 920 Alarms One of the most versatile features of the Watlow Series 920 is its capability for alarms. The alarms can be automatic signals for process error or temperature related event-type actions in your system. To use the alarms to their fullest extent, you need to understand what they are and what they will do. Here’s an overview of the different alarm parameters again. Although you may already be aware of the alarms, notice how these parameters interact.
Alarm Types There are three Alarm Types for each alarm. ALTYPl and ALTYP2 are the prompts for Alarm 1 and Alarm 2, respectively. The choices are: Process alarm (P), or Deviation alarm (D). For review, a “process” type alarm is one that is set at a fixed degree distance, either positive or negative, from the mean O°F or O°C. A “deviation” type alarm is always a fixed degree distance, positive or negative, from Set Point (SP).
The Operating Band Now we need to set the alarm limits. In doing so, you’ll define an “operating band” where you want system temperature (or your controlled variable) to be . “OK” and alarm-free. By selecting an alarm type (ALTYP), and then the alarm limits (AXL, AXH), you define the Operating Band. The extreme limits of the Operating Band are defined by the 920s high and low ranges, see the table below. The following limits are enabled when RAL and RAH are at their maximum default values.
Alarm Limits You can set up alarm bands with the two available alarms. Each of the two alarms has a high and a low limit point, indicated by the‘I” or “H” designation. You specify in the Operating Data where you want Al L, Al H, A2L, and A2H. The first two examples below show one band inside the other. However, you could use Al L-Al H as a band below both set point, and A2L-A2H. Figure 34 Alarm limits for Alarms 1 and 2 with “process” type alarm. (ALlYPi =P, ALTYP2zP) A2H Temp SP New SP I AlH AIL . .
Alarm function is either “latching” or “non-latching.” Latching is a means of “saving” indication of an alarm event for the operator to clear manually. A latching alarm requires the operator to manually clear it with the ENTER key when ACTUAL returns to within the limits. A non-latching alarm clears itself automatically when ACTUAL returns to within the limits. It’s your choice. Here again is the "LAT” information from the Operating Parameters: LAT Defines AlarmFunction: NLAT = Non latching.
Appendix Series 920 Specifications Control Mode . . . l Microprocessor-based, user selectable modes. Single input, dual control outputs, dual auxiliary outputs. 99 step programmer with up to 10 profiles. Control outputs: User selectable as: Heat, Heat/Cool, Cool, Cool/Heat. Outputs independent, or related via dead band. ON/OFF: 3°F (1.7°C) switching hysteresis. PID parameters. Proportional band: 0 to 900°F (0 to 500°C), or 0 to 500 units, 0.0 to 90.0°F (0.0 to 50.0°C) for 0.l° RTD inputs. Reset: 0.
Offset of input signal, ±90°F (±50°C), ±50 PVU’s, front panel adjustable ±9.0°F (±5.0°C) for 0.l° units °F, °C, or process variable units are user selectable l . Output - Control (Single or Dual) Output #2 user selectable as cool action Solid state relay, Form A, 0.5A @ 24VAC minimum, 264VAC maximum, 10mA minimum load, opto isolated, zero cross switching.
Series 920 Model Number Breakdown |9|2|O|A|-| Control Series 920 = Input 2 3 4 = = = |o |o|o| Single channel, microprocessor based, dual output, ramping controller, 99 steps, 1/4 DIN. Type J, K, T thermocouple, 0-5VDC, 1° RTD Type J, K, T thermocouple, 4-20mA, 0.1° RTD Type R, S, B thermocouple #1 output B = Solid state relay, Form A, 0.
J, K, & T Thermocouple Field Calibration Procedure Equipment Required T/C calibrator set at 0°C/32°F OR Type “J”, “K”, or “T” Reference Compensator with reference junction at 0°C/32°F. Type “J”, “K”, or “T” T/C extension wire. 4-1/2 digit Digital Voltmeter (DVM). l l l Setup and Calibration J NOTE: Before calibration on an installed control, make sure all data and parameters are documented. 1.
R, S, & B Thermocouple Field Calibration Procedure Equipment Required l l l l Type “R” Reference Compensator with reference junction at 0°C/32° F OR T/C calibrator. Type “R” T/C Extension Wire. Copper wire. Precision Millivolt Source. Setup and Calibration J NOTE: Before calibration on an installed control, make sure all data and parameters are documented. 1. Connect the precision millivolt source to Terminals #6 and #8. See the figure below.
RTD Field Calibration Procedure Equipment Required 100 ohm precision decade resistance box with 0.00 ohms resolution. 4-1/2 digit, digital voltmeter (DVM). l l Setup and Calibration 1 NOTE: Before calibration on an installed control, make sure all data and parameters are documented. 1. Connect the precision decade box to #1 , #2, and #3 of the Series 920 terminal strip as shown in the figure below.
6. Press the MODE key until the HOF XX.XX parameter appears on the alphanumeric display. (The decimal point will not appear on the display of your control.) Use the UP/DOWN keys to adjust the alphanumeric display on the 920 to match the reading on the DVM. Once the two readings match, press the ENTER key. 7. Press the MODE key until ATZ XXXX appears on the alphanumeric display. Set the precision decade box to the correct LOW setting from Table 12 that corresponds to the type of 920 unit you have.
Process Field Calibration Procedure Equipment Required 4-1/2 digit, digital voltmeter (DVM). Precision voltage/current source. l l Set-up and Calibration J NOTE: Before calibration on an installed control, make sure all data and parameters are documented. 1. Connect the voltage/current source to #4 Positive and #5 Negative on the Series 920 terminal strip. See the figure below. Series 920 Terminal Strip Figure 39 Voltage/Current Source to Series 920 Connection Diagram Voltage/Current Source , 66 . 2.
Glossary This glossary includes general thermal systemcontrol terms. ACCESS( ): In the SETUP menu of the Series 920, an ACCESS number (0, 1, 3,5) must be selected to enter the personality of your Series 920 into the CALIB, PID, MANUAL, and SPCLFUNC parameters. Actual display data: Displayed information which gives the operator/programmer real or "actual” data, i.e., actual process temperature. See “Programmed display data.
CALIB: When ACCESS (0) is entered under the SETUP menu, the CALIB parameters appear. These parameters setup the Real Time and the calibration offset of the process variable. C/F/U: Accepts the sensor input and scales it to degrees Celsius, Fahrenheit, or Units of measure. This parameter will not appear if DIP switch #7 is ON. Closed loop: Control system with a sensing device for process variable feedback. CLR FILE: Allows the operator to clear a file of the Series 920.
Deviation: The difference between the value of the controlled variable and the value at which it is being controlled. Default parameters: The parameters, or programmed instructions, which are permanently stored in microprocessor software to provide a data base. DIP switch: A Dual In-line Package switch. DIN: Deutsche Industrial Norms, a widely-recognized German standard for engineering units.
HOUR: The HOUR parameter has three meanings, depending upon which menu you are in. PROGRAM menu - The number of hours, in combination with the MIN and SEC parameters, that equal the total step time to achieve the temperature. Under the AUTOSTART step type, the hours that the 920 will wait for the time-of-day clock before AUTOSTART takes place. SETUP menu - Represents the SYSTEM 24 hour time-of-day clock. Midnight = 0 hours.
MANUAL: When ACCESS (3) is selected under the SETUP mode of the Series 920, the MANUAL parameter appears. MN: The MIN parameter has three meanings depending upon which parameter you are in. PROGRAM menu - The number of minutes that equal total step time to achieve the temperature of the Series 920. Under the AUTOSTART step type in the PROGRAM menu, it represents the minutes that the 920 will wait for on the time-ofday clock before AUTOSTART takes place.
PID: When ACCESS (1) is entered in the Series 920, the PID parameters will appear. These parameters consist of Proportional, Integral (auto reset), and Derivative (rate) actions. PID control: Proportioning control with auto-reset and rate. PRG: This parameter determines whether the set point ramp as a function of time or ramp rate. Process Variable: Thermal system element to be regulated, such as time temperature, relative humidity, etc.
RS H: A reset (integral) heating control action that automatically eliminates offset, or “droop”, between set point and actual process temperature in a proportional control. Expressed in minutes. This parameter will not appear if OUT = CL or PB H is set to 0. RT: Represents the rate at which the set point changes in a given time. RT C: The Rate (derivative) Cooling function detemined by how fast the error being corrected is increasing. Expressed in minutes.
SYSTEM: Switching sensitivity: One of three main level operating parameters. From the SYSTEM menu, you can generate a non-ramping set point (fixed), manipulate Events 1 and 2, clear error codes and latching alarms. In ON/OFF controls, the temperature change necessary to change the output from full ON to full OFF (3°F or 1.7°C in the Series 929). Thermal System: A regulated environment consisting of a heat source, heat transfer medium, sensing device and a process variable control instrument.
AB Accuracy, 60 Actual and Alphanumeric Display Area, 12, Fig. 6 Alarms, Clearing, 41,45,58,78 Codes, 79 Configuration, 54. Definition, 67 Function, 58 Limits, 57 Relays, 58 Rules, 78 Types, 55 ALTYP1 & 2, 48,67 AUTOSTART Step Type, 17,52,67 Auxiliary Output, 27, Fig. 17 AUX1 & 2,47,67 AXL, AXH, 45,67 C CAL, 45,67 Calibration, 62 C/F/U, 12,47,68 Chart Recorder, 33 Clean Input Power, The Do’s and Don’ts, 21 Clearing Memory, 14 CLR FILE, 48 COM, COM ID, 48,68 Combination Differential Filter, 23, Fig.
Sensor Wring, 27 RUN Menu, 79 Running Your Series 920, 19, Fig. 8 Nested Loop, 39 NLAT, 48 Alarms, 58 No Output, 30, Fig. 23 Noise, Suppression Device Ratings, 22, Table 7 O Open the 920, How to, 8, Fig. 2 Operating, Band, 56 Environment, 60 Modes, 10, Fig. 4 Operator Interface, 59 OUT, 47,71 Output AUX, 60 Control, 60 Event, 37 Wiring, 27 P Packing List, 7 Panel Cutout, 25 PB C & H, 45, 46 PID,45,71, 76 Power, Wiring, 26, Fig.
Warranty Information The Watlow Series 920 is warranted to be free of defects in material and workmanship for 36 months after delivery to the first purchaser for use, providing that the units have not been misapplied. Since Watlow has no control over their use, and sometimes misuse, we cannot guarantee against failure.
Series 920 Error Codes/Alarms ER1 Error Codes and Actions 9 10 11 12 13 14 15 16 20 21 22 Internal RAM failure; consult factory. External RAM failure; consult factory. Bad battery error; consult factory. A/D conversion error, or input sensor error. For the input type selected, verify that the corresponding sensor input is OK, (TC, RTD, 0-5VDC or 4-20mA). If sensor is OK, consult factory. High reference out of limit. Check calibration procedure. If not OK, consult factory.
Clearing an Error Code Series 920 Response to Error Codes To clear an Error Code from the alphanumeric display, first correct the problem, then return to the SYSTEM menu. Use the MODE keys to reach the ER1 or ER2 parameter and press ENTER. Press ENTER or transmit a 0. If the code returns, or if the 920 replies to a data communicated “? ER1 ” or “? ER2” query with the same code, the problem still exists. Refer to the Series 920 manual or the Series 920 Data Communications Manual.
Series 920 Quick Reference Main Menu @ - To SYSTEM Menu - To PROGRAM Menu - To SETUP Menu SYSTEM Menu To SYSTEM Prompt PROGRAM Menu To SYSTEM Watlow Controls, 1241 Bundy Blvd.
