General Description - Watlow 945 Series User Manual

Chapter 1
The Watlow Series 945,
A Microprocessor-Based Control
Single Input -
Type J, K, T, N, R, S, B, C or Pt2
Thermocouple, RTD or Process
Remote Set
Point Input -
0-5VDC or 4-20mA
RS-422A, RS423A (RS-232C
compatible), or EIA-485
Optional Computer Interface

General Description

Welcome to the Watlow Series 945, a 1/4 DIN microprocessor-based temperature
control. It has a single input, remote set point input, dual output, and dual alarm.
The 945 is an auto-tuning control when Output 1 is in the heat mode, and features
Automatic/Manual capability with bumpless transfer. In the Auto mode, the 945 has
closed loop control with sensory feedback, while the Manual mode has open loop
control with user defined output power level. The 945 accepts a variety of thermo-
couples, as shown above, along with RTD, or process input. The primary output is
heat or cool, while the secondary output can be heat, cool or none. An optional
retransmit output is offered in place of one of the alarms. Selectable as retransmit
of set point or process variable. Units with communications feature data logging
with user selectable table, chart or SPC (Statistical Process Control) printout of data.
With the Series 945 you can select either PID or ON/OFF for Output 1 or 2. Input a
complete set of PID parameters for both outputs, including proportional band, reset/
integral and rate/derivative. By setting either output's proportional band to zero, the
Series 945 becomes a simple ON/OFF control with the switching differential select-
able under the HYS (hysteresis) parameter in the Setup menu.
Operator-friendly features include automatic LED indicators to aid in monitoring and
setup, as well as a calibration offset at the front panel. The Watlow Series 945
automatically stores all information in a non-volatile memory.
Getting Started, Chapter 1
PID or ON/OFF, User Selectable
Retransmit Output
(Up to 10 Slaves)
Process Set Point
Output 1
Auto-tuning
(Heat only)
Starting Out
Dual Outputs -
Output 1 -
Heat or Cool
Output 2 -
Heat, Cool or None
Dual Alarms
Output 1 or 2
Percent Power
WATLOW Series 945 User's Manual
Starting Out
Figure 1 -
Series 945 Input and
Output Overview
3