Series 945 High/Low Limit Control User's Manual Watlow Controls, 1241 Bundy Blvd., P.O. Box 5580, Winona, MN 55987-5580, Phone: 507/454-5300, Fax: 507/452-4507 W945-LMT1-9345 November, 1993 $10.00 Made in the U.S.A.
Starting Out Starting Out With The Series 945, A Microprocessor-Based Limit Control Figure 1 Series 945 Input and Output Overview Signal to Drive an Audible Alarm Single Input Type J, K, T, N, C or Pt2 Thermocouple, RTD or Process RS-422A, RS423A (RS-232C compatible), or EIA-485 Optional Computer Interface Dual Alarm Relay Outputs General Description Welcome to the Series 945, a 1/4 DIN microprocessor-based, audible alarm, dual alarm relay, single input, high-low limit control.
Power Wiring How to Wire the Series 945 945A-2CA2-AJAP Terminal The Series 945 wiring is illustrated by model number option. Check the unit sticker on the control (see right) and compare your model number to those shown here and also the model number breakdown in the Appendix of this manual. Series 945 internal circuits appear "inside" the line drawing of the 945, while connections and terminal designations appear "outside" the line drawing. All outputs are referenced to a de-energized state.
Input Wiring Sensor Installation Guidelines We suggest you mount the sensor at a location in your process or system where it reads an average temperature. Choose a point that will adequately represent the process temperature without being overly reactive. For thermocouple inputs: Use an isolated or ungrounded thermocouple if an external 4-20mA output device with a non-isolated circuit common is connected. Extension wire must be of the same alloy as the thermocouple itself to limit errors.
Wiring 0 - 5VDC Process or Remote Set Point Input + 1 945A - 2 _ _ _ - _ 000 V DC 3 945A - 3 _ _ _ - _ 000 Input impedance: 100KΩ Figure 6 0 - 5 VDC Process Input Wiring. 4 - 20mA Process or Remote Set Point Input + 1 2 3 945A - 2 _ _ _ - _ 000 IDC 4-20mA process input: 249Ω. A jumper must be installed between Terminal #2 and 3. 945A - 3 _ _ _ - _ 000 Figure 7 4-20mA Process Input Wiring.
Alarm Wiring Alarm Outputs, Form A or B, 6 Amp Mechanical Relay Figure 9 Alarms Option Wiring Diagram. 945A- _ _ _ 2 - _ 000 Off state impedance is 20KΩ minimum. 24 Output 3 25 26 Output 2 27 Fuse L1 Alarm AL2 2 Fuse L2 L1 AL2 1 Alarm L2 Changing the Position of an Alarm Jumper Whenever you change the position of a jumper, follow this procedure: 1. Remove power from the Series 945. Turn the front panel screw 90° counterclockwise. 2.
Alarms Using Alarms The Series 945 has two alarm types, Process or Deviation. A Process alarm sets an absolute temperature when the process exceeds that absolute temperature limit. A Deviation alarm alerts the operator when the process strays too far from set point. The reference for the deviation alarm is the process value. Both Process and Deviation alarms can be latching or non-latching. The operator must manually reset a latching alarm before the alarm will reset.
Keys/Displays How to Use the Keys and Displays NOTE: The Upper display will automatically display the process value after 1 minute without key strokes. Upper Display Red, 0.56" high, seven segment, four digit LED display, indicating either process actual temperature, the operating parameter values, or an open sensor. When powering up, the Process display will be blank for 8 seconds. Figure 12 Series 945 Displays F&C Indicates the displayed temperature is in degrees Fahrenheit (F) or Celsius (C).
Setup How to Set the DIP Switch The Series 945 has a Dual In-line Package (DIP) switch inside the control on the A007-1954 circuit board (middle board). The location of the board and switches appear below. The switches are clearly numbered. When Switch #1 is ON, the Setup parameters can be viewed but not changed. Switch #2 is not used. The factory default is OFF.
Setup LOC Lock: Selects the level of operator lock-out. Range: 0 - 2 Default: 0 The levels of operator lock-out are defined as follows: LOC 0: All operating parameters may be viewed or changed. LOC 1: No calibration offset adjustments permitted. LOC 2: No adjustments permitted. In NOTE: In the deviation mode, rL and rH only effect the target set point values. 10 Input: Selects the sensor input type. Only those input types which are compatible with your unit will appear.
Protocol: Selects the communication protocol. This parameter will appear if your Series 945 has communications. FULL = ANSI X3.28 2.2 - A.3 On = XON - XOFF Range: FULL or On Default: FULL Setup Prot Address: Selects the address for this unit if Prot = FULL. This parameter will appear if your Series 945 has communications. Range: 0 to 31 Default: 0 Addr Log: Selects the data logging function for a printout of the data. Appears if your 945 has communications, Prot = On, and Log = tAbL or CHrt.
Setup Setup Menu Use this page as a master copy for configuring your Series 945. Do not enter any values here; make photocopies instead. Table 2 Setup Menu Prompts and Descriptions. Setup Parameters Range Factory Default LOC 0-2 0 In J, K (appears as H), t, n, c, Pt2, rtd, rt.d, 0-5, 420 Dependent on model number. t dEC 0, 0.0, or 0.00 Dependent on input type. 0 C_F C or F Will not appear if In = 0-5 or 420. F rL rL to rH Input selection dependent.
Operation M Mode Key NOTE: ACt ALO ( ) AHI ( ) CAL OFF ( ) The Upper display will always return to the process value after 1 minute without key strokes. Represents target set point for deviation alarms, or remains blank Figure 15 The Operation Menu. Operation Parameters Target Set Point or Blank: Displays the target set point while using deviation alarm only. Display remains blank while in the process alarm mode.
Calibration Before attempting to calibrate, make sure you have the proper equipment called for in each procedure. Entering the Calibration Menu Enter the Calibration Menu to change the configuration of the dFL (default language) parameter. Several parameters are dependent on the dFL parameter, they are listed below. It is a good idea to change this parameter, if necessary, before entering the Setup menu. The factory configures your unit to your preference, but can be changed at any time.
Calibration Calibration Menu CAL ( ) YES to calibrate, No skips to display test. tCL ( ) Input 0.00mV for low thermocouple input. tCH ( ) Input 50.00mV (16.035 for r, S or b units) for high thermocouple input. tC ( ) Connect a "J" T/C compensator, with inputs shorted. T/C units only. rLO ( ) Connect the JIS RTD low resistance per model number. rHI ( ) Connect the JIS RTD high resistance per model number. O U ( ) Set the voltage source to 0.000 volts.
T/C and RTD Thermocouple Field Calibration Procedure Equipment Required: • • Type "J" or "R" Reference Compensator with reference junction at 32°F/0°C, OR Type "J" or "R" Thermocouple Calibrator set at 32°F/0°C. Precision millivolt source, 0-50mV min. range, 0.01mV resolution Setup And Calibration 1. Connect the AC line voltage L1, L2, and ground to the proper terminals. 2. Connect the millivolt source to Terminal #9 Negative and Terminal #7 Positive on the Series 945 terminal strip.
0 - 5V/4-20mA Input 0 - 5 Volt Input Field Calibration Procedure Equipment Required: • Precision voltage source 0-5 volt minimum range with 0.001 volt resolution. Setup And Calibration 1. Connect the AC line voltage L1, L2, and ground to the proper terminals on the 945. 2. Connect the voltage/current source to Terminal #1 and #3 on the Series 945 terminal strip. Use regular 20 - 24 gauge wire. 3. Apply power to the unit and allow it to warm up for 15 minutes.
Specifications Control Mode • High/Low limit. • RS-422A,RS423A, or EIA-485 data communications available. Operator Interface • Membrane front panel. • Dual, four digit 0.56" LED displays. • MODE, UP, DOWN, and ALARM CLEAR keys. Input • Thermocouple, RTD, and electrical process input. • Automatic cold junction compensation for thermocouple. • RTD input 2 or 3 wire, platinum, 100 ohm @ 0°C software selectable, JIS curve #3916 (0.003916 Ω/Ω/°C) or DIN curve #3850 (0.003850 Ω/Ω/°C).
Communications • Serial data communications. • RS-422A or RS-423A (RS-232C compatible) or EIA-485. • ANSI X3.28 protocol, or XON/XOFF protocol. • Isolated. • Data logging. • #6 compression type screw terminals. Specifications Power • 120/240VAC + 10%, -15%, 50/60Hz, ± 5%. • 16VA maximum. • Data retention upon power failure via non volatile memory. Operating Environment • 32 to 149°F/0 to 65°C. • 0 to 90% RH, non-condensing. Dimensions • Height: • Width: • Overall depth: • Behind panel depth: • Weight: 3.
Model No. Series 945 High/Low Limit Control User's Manual Watlow Controls, 1241 Bundy Blvd., P.O.
