Watlow Series SD Limit - Manual (Page 4)

Wa t l o w S e r i e s S D L i m i t
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C h a p t e r 1 O v e r v i e w
The Watlow Series SD family of microprocessor-
based limit controllers is available in 1/32, 1/16, 1/8
and 1/4 DIN panel mount sizes*. The Series SD limit is
added to applications to prevent over or under process
conditions. The Series SD limit provides safety assur-
ances against instances where a process runaway con-
dition occurs as a result of a failed sensor or output de-
vice.
The Series SD limit is recommended for any appli-
cation where system runaway could result in large
product scrap costs, damage to system equipment,
potenial fire hazard or risk to personnel. All Series SD
limits are Factory Mutual approved.
The Series SD limit has a single, universal input
that accepts various thermocouples, RTDs (resistive
temperature devices) or process inputs. (See the Speci-
fications in the Appendix for further details).
The Series SD limit offers up to two outputs on the
1/32 DIN, and up to three outputs on all others. Out-
put 1 is always a mechanical relay operating as a
latching limit output. Any mechanical relay output can
be configured as a latching limit output. These can be
configured as a low limit, high limit or low/high limit.
Outputs 2 and 3 can be also configured as latching or
non-latching alarms. Standard Series SD limit features
include an IP65/NEMA 4X front panel rating; CE compli-
ance; dual, four-digit displays. A low-voltage model is also
available.
Advanced features include Modbus, EIA-485 serial
communications to interface with PC software applica-
tions; INFOSENSE™ technology that provides low-
cost, high-accuracy thermal sensing; and infrared re-
mote communication for easy-to-use setup and moni-
toring.***
Other operator-friendly features include LED indi-
cators to aid in monitoring and setting up the con-
troller. The Watlow Series SD limit automatically
stores all information in non-volatile memory and pro-
vides an additional back-up for user-selected settings.
For more information on these and all other prod-
uct features, refer to the Features Chapter and the Ap-
pendix.
* Also available in a temperature controller version.
** The 1/32 DIN limit comes only with a red
left and green right display.
*** Not available in the 1/32 DIN size.
Overview
1
Control Input
Output 1
Limit
Output 2
Limit, Alarm or Communications
Output 3
Limit or Alarm *
Infrared
Configure** Infrared
Monitor**
*1/32 DIN cannot have an Output 3.
**Infrared option is not available on 1/32 DIN.
RESET
2 3 1
LIMIT SD
2 3 2 3 1
Figure 2 — Series SD limit inputs and outputs.