Watlow Series 920 Microprocessor-Based Ramping Control - Manual (Page 7)

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. You can use events, based on time, temperature,
or other process variables, to trigger peripheral equipment or processes.
Operator-friendly features include automatic entry codes or “prompts” to aid in
setup. When there’s a power outage, the Watlow Series 920 stores all informa-
tion in a non-volatile memory.
When you first apply power, the unit will “come up” with default values for set
points, alarm points and control parameter. These default values provide
minimum operating information for the control until you program in the desired
data. The default values are listed in the Master Step Menus and Charts,
pp. 41-50.
Remove the Series 920 carefully from its shipping container. Be sure to set
this literature aside where it will not be discarded.
Packing List
Included with your Watlow Series 920 are two mounting brackets with integral
screws, and this manual. If your unit has communications, the “How to Use
Data Communications with the Watlow Series 922” manual is also included.
Put Your Control to Work-Three Steps
Once your control is installed and wired, getting the Series 920 “up and run-
ning” is a three-part process:
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First, match the control’s “personality”, to your system in what we call the
SETUP menu; input type, units of measure, range, calibration offset, output
action, alarm type, lock-out.
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Second, tune the control making final PID entries.
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Third, enter up to ten separate profiles in the PROGRAM menu.
WATLOW Series 920 User’s Manual 7