Watlow Series 942 Controller

Key configuration parameters (Setup menu)

Parameter Category Core Parameter Function Description Default Values

Security and Permission LOC Operation Permission Lock (Level 0-3): Level 0 Full Permission, Level 3 Only View Setpoint/Process Values 0

Input configuration In Select input type (such as J, K, RTD, 4-20, etc.) J or r

Temperature unit (° F/° C), only displays F when input as thermocouple/RTD

The upper and lower limits of the range for the rL/rH set point/process input, as well as the default range for scaling and retransmitting the output range of the sensor

Output configuration Ot1/Ot2 output 1/2 action type (ht heating/CL cooling/no off) ht/CL

HYS1/HYS2 output 1/2 ON/OFF switching hysteresis (effective when Pb=0) 3 ° F

Alarm and event Ot3/Ot4 auxiliary output 3/4 function (AL alarm/Ent event/PrOC retransmission) AL/PrOC

AL1/AL2 alarm type (Pr process alarm/DE deviation alarm) Pr

Programming configuration PtYP program type (ti time basis/ratE ramp rate basis) ti

GSD constant temperature deviation window (program pauses when out of range) 0 (disabled)

Power outage recovery Pout program recovery method after power outage (Cont continue/HOLD hold/Abrt abort) Cont

Communication configuration: bAUD baud rate (300-9600), only models with communication function display 1200

Addr device address (0-31), only displaying 0 under FULL protocol

Operation menu parameters (Operation menu)

Setpoint (SP): Adjust the control target value within the range of rL~rH, and display OFF (disable all outputs) when it is lower than rL.

PID parameters (Pb1/Pr2, rE1/rE2, rA1/rA2): proportional band, reset/integral, rate/derivative, automatically generated after automatic tuning, or manually adjustable.

Automatic tuning (Aut): Only output 1 for heating display, select tuning rate (1 slow/2/3 fast), and the controller automatically optimizes PID parameters after startup.

Alarm setting (A1LO/A1HI, A2LO/A2HI): Process alarm setting upper and lower limits (Pr type) or deviation alarm offset (dE type).

Program Programming and Running

Fundamentals of Programming

Program structure: Up to 24 steps, each step can be selected from four types: StPt (Setpoint Slope), SoAh (Constant Temperature Holding), JL (Jump Loop), and End (Program End), supporting multiple program concatenation (a new program can start after one End step).

Programming entrance: Select Prog=YES from the Operation menu to enter the Program menu. Press the StEP parameter to select steps (1-24), and press StYP to select the step type.

Detailed explanation of four step programming methods

1. Set point step (StPt)

Core parameters:

SP: Target Set Point (rL~rH).

Time basis (PtYP=ti): HOUr/Min/SEC, total time is the sum of the three (0-23h59m59s).

Rate basis (PtYP=rAtE): rAtE, temperature change rate (0-360 ° F/min or 0-200 ° C/min).

Ent1/Ent2: On/Off status of event 1/2, displayed only when Ot3/Ot4 is set to Ent.

Example: Step 1 is set to StPt, SP=75 ° F, Min=0, SEC=1, Ent1=OFF, achieving the initial setting of reaching 75 ° F within 1 second.

2. Constant temperature step (SoAh)

Core parameters: HOUr/Min/SEC (constant temperature duration), Ent1/Ent2 (event switch), no SP parameter (inherited from the previous set point).

Example: Set Step 3 to SoAh, Min=0, SEC=25, Ent1=On, achieve 25 seconds of constant temperature and trigger Event 1.

3. Jump loop step (JL)

Core parameters:

JS: Jump to the target step (must be smaller than the current step, cannot jump to itself).

JC: Jump count (0=infinite loop, 1-100=finite loop).

Example: Set Step 6 to JL, JS=2, JC=1, implement a jump to Step 2 and repeat once (execute Steps 2-5 twice in total).

4. End step

Core parameters: End (HOLD remains in the last state/OFF closes all outputs/OFFA closes control outputs, retains alarms).

Example: Step 4 is set to End, End=OFF. After the program ends, all outputs are turned off, and 'lower' displays' OFF '.

Program Execution and Control

Start program: In the non Setup menu interface, press the HOLD/RUN button, the RUN LED flashes, select the Start Step (StP), then press the HOLD/RUN button to confirm, the RUN LED stays on, and the program starts.

Pause and Resume: Press the HOLD/RUN button once to pause (RUN LED flashes); Press the HOLD/RUN key again to switch to the rESU parameter, and press the HOLD/RUN key to resume operation (only when the program has not been modified).

View operating status: Press the MODE key to switch parameters in the RUN menu, where you can view remaining time (HOUr/Min/SEC), current rate (rAtE), event status (Ent1/Ent2), etc.

Programming Example (Slope Constant Temperature Cycle)

Requirement: Initial temperature of 75 ° F → 25 seconds to rise to 100 ° F (event 1 activated) → 25 seconds constant temperature → 25 seconds to rise to 125 ° F (event 2 activated) → 25 seconds constant temperature → jump to step 1 and repeat twice → maintain the final state.

Step by step SP (° F) Time (minutes: seconds) Ent1 Ent2 JS JC End

1 StPt 75 0:01 OFF OFF - - -

2 StPt 100 0:25 ON OFF - - -

3 SoAh - 0:25 ON OFF - - -

4 StPt 125 0:25 OFF ON - - -

5 SoAh - 0:25 ON OFF - - -

6 JL - - - - 1 2 -

7 End - - - - - - HOLd

Tuning operation (automatic and manual)