The limit control
is a microprocessor based high or low limit
safety device with a latching output. The relay contacts open if
an abnormal condition during the process is higher than the
high limit set point or lower than the low limit set point.
Digital communication RS-485 is available as an additional
option. This option allows L91 to be integrated with supervisory
control system. An alarm output is another option. A variety of
alarm function and alarm modes can be programmed for a
specific application. The DC power supply output option is used
for an external sensor or transmitter. The event input option can
be programmed for remote reset or remote lock signal input.
The limit annunciator option can be used to energize an
external audible alarm when limit is reached.
Ma retransmission option of Process variable or setpoint is also
available.
and simple
are the main features of L91.
NOTE: * Volt and Milliamp Inputs are NOT FM Approved.
L91
18-bit A to D
fast sampling rate
Two kinds of method can be used to program L91. 1. use keys
on front panel to program the unit manually, 2. Use a PC and
setup software to program the unit via RS-485 port.
High accuracy, maximum flexibility, fast response
user friendly prompts
The unit is powered by 90-264 VAC or an optional 11-26
VAC/VDC power supply. It incorporates a 2 amp. form C relay for
limit control, a universal input which is fully programmable for
RTD PT100, thermocouple types J, K, T, E, B, R, S, N, L, 0~60mVolt,
Volt* and Milliamps*. An optional second output is available for
one of the following functions: alarm output, RS-485
communication, MA output, DC power supply output, limit
annunciator output and event input. Alternative output options
include; relay, SSR drive, Triac and Ma for retransmission.
All mutually exclusive.
The input signal is digitized by using a
converter. Its
(5 times/second) allows the L91 to respond
quickly to input changes.
L91
18-bit A to D
fast sampling rate
Two kinds of method can be used to program L91. 1. use keys
on front panel to program the unit manually, 2. Use a PC and
setup software to program the unit via RS-485 port.
High accuracy, maximum flexibility, fast response
user friendly prompts
The unit is powered by 90-264 VAC or an optional 11-26
VAC/VDC power supply. It incorporates a 2 amp. form C relay for
limit control, a universal input which is fully programmable for
RTD PT100, thermocouple types J, K, T, E, B, R, S, N, L, 0~60mVolt,
Volt* and Milliamps*. An optional second output is available for
one of the following functions: alarm output, RS-485
communication, MA output, DC power supply output, limit
annunciator output and event input. Alternative output options
include; relay, SSR drive, Triac and Ma for retransmission.
All mutually exclusive.
The input signal is digitized by using a
converter. Its
(5 times/second) allows the L91 to respond
quickly to input changes.
Chapter 1 Over view
Chapter 1 Over view
1-1 General
1-1 General
5
UM L91-Rev 8
