Watlow Series 942 - Manual (Page 4)

Starting Out
Getting Started, Chapter 1 4
WATLOW Series 942 User's Manual
Starting Out
General Description
Welcome to the Watlow Series 942, a 1/4 DIN microprocessor-based ramping
temperature control. It is a single input, dual output, auto-tuning control with 24
step program capability and easy fixed set point operation. The 942 accepts a
Type J, K, T, N, R, S, B, C or Platinel 2 thermocouple, RTD, or process input. The
primary output is heating or cooling, while the secondary output can be heating,
cooling or none.
With the Series 942 you can select either PID or ON/OFF for Output 1 or 2. You
can input a complete set of PID parameters for both outputs, including proportional
band, reset/integral and rate/derivative. You can also select automatic tuning for
Output 1 while in the heating mode. By setting either output's proportional band to
zero, the Series 942 becomes a simple ON/OFF control with the switching differen-
tial selectable under the HYS Setup parameter.
Two optional auxiliary outputs may be alarms or events. An event is an ON/OFF
mechanical relay output. Events are based on time, and can trigger peripheral
equipment or processes. An optional retransmit output is offered in lieu of one of
the auxiliary outputs. Select either retransmit of process variable or set point.
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 942
automatically stores all information in a non-volatile memory.
Retransmit Output
(Up to 10 Slaves)
Process Set Point
Dual Alarms/Events
Output 1
Auto-tuning
(Heat only)
Output 1
Heat or Cool
RS-422A, RS423A
(RS-232C compat-
ible), or EIA-485
Optional Computer
Interface
Single Input -
Type J, K, T, N, R, S, B, C or Pt2
Thermocouple, RTD or Process
Chapter 1
The Watlow Series 942,
A Microprocessor-Based Control
Dual Outputs-
PID or ON/OFF, User Selectable
Output 2
Heat, Cool or None
Figure 1 -
Series 942 Input and
Output Overview.