1 Introduction
The TC10-L is an FM (both FM3545 and FM3810) approved limit controller that can be configured either as a high limit or as a low limit
controller by a user.
The TC10-L features
- universal input,
- two alarm outputs,
- retransmission output,
- a timer to count the total time the Set Point has been exceeded,
- a register to retain the maximum (or the minimum) measure reached.
- The RS485 communication interface is available optionally.
2 Limiter function
The relay of the output 2 operates in fail-safe mode (relay de-energized during shutdown condition) and latching mode.
OUT 2 turns OFF (in this document this condition will be named shutdown) when:
The instrument is configured as a high limiter (Hi.Lo = Hi) and the measured value is greater than limiter threshold [“SP” parameter].
The instrument is configured as a low limiter (Hi.Lo = Lo) and the measured value is lower than limiter threshold.
Out 2 remains OFF until the condition which generated the shutdown, no longer exists and the Confirming action (rearm) has been
performed.
During a shutdown (Out 2 is OFF) the upper display will be red.
Confirming action (rearm) can be performed in two different way:
- by pressing the
key [when “diS” parameter is set to “but”] but it will be accepted only when the condition which generated the
shutdown, no longer exists (EX lamp is OFF) and the set point is shown on the lower display (see “normal display” in “Navigation access”)
- by momentarily closing the digital input (by an external dry contact) [when diS parameter is set to “di”] but it will be accepted only
when the condition which generated the shutdown, no longer exists.
We define also that the time duration of the shutdown condition, stored by the instrument, will be the time from Out 2 goes OFF (shut-
down start) and the condition that generate the shutdown no longer exists.
The confirmation action is not part of this time count.
The time duration of the shutdown condition and max/min measured values are stored in memory and available for viewing (see “navi-
gation access”) until the next shutdown condition occurs.
These informations are lost at power down.
2.1 High limit control
PV
SP
Process Value
(in eng. units)
Set Point
(a)
(Editing mode)
Limit
Control
High
Limiter
Exceeded
indication
EX
OUT
PK
HI
AL1
AL2
TC10-L
Output
(b)
(c)
(d)
(e)
The HI lamp (d) is ON
When a measured value (a) is higher than the set point (b),“EX” lamp (e) lights, “OUT” lamp (b) turns ON and the limit output relay (Out 2)
is de-energized.
EX lamp (e) turns off when PV goes into normal condition, while the ”OUT” lamp (c) stays on as it is.
The out (c) lamp turns off only when the EX lamp (e) is off and a confirming operation (rearm) has been done by an operator.
The way to confirm are (according to the “diS” parameter):
- pressing
key for more than 3 seconds or
- by DI1.
Output relay is de-energized whenever “OUT” lamp is on.
Check the “HYS” parameter value if the EX lamp (e) is not turn off when PV (a) is lower than SP (b).
SP
HYS
PV
(A)
(B)
(C)
(A)
(B)
(D)
EXCEEDED
LAMP
OUT
LAMP
lit
off
OUTPUT
RELAY
confirmation
(accepted)
confirmation
(not accepted)
lit
off
Energized
De-energized
OFF
OFF
OFF
Lit
Lit
OFF
Lit
ON
OFF
ON
OFF
Lit
OFF
When the EX lamp (e) is ON but PV (a) is lower than SP (b), the upper display will be in green colour and it shows that the PV is in the
hysteresis area
SP
HYS
PV
(A)
(B)
(C)
EXCEEDED
LAMP
OUT
LAMP
lit
off
OUTPUT
RELAY
confirmation
(accepted)
lit
off
Energized
De-energized
Upper
display
colour
(D)
2.2 Low limit control
The HI lamp (d) is OFF
When a measured value (a) is lower than the setpoint (b), “EX” lamp (e) lights, “OUT” lamp (c) turns ON and the limit output relay is
de-energized then.
“EX” (e) lamp turns off when PV goes into normal condition, while the “OUT” lamp (c) lamp stays on as it is.
The out (c) lamp turns off only when the EX lamp (e) is off and a confirming operation (rearm) has been done by an operator.
The way to confirm are (according to the “diS” parameter):
- pressing
key for more than 3 seconds or
- by DI1.
The confirming operation is not accepted during PV exceeds SP (D) (during EXCEEDED lamp lights*). State of output relay is de-energized
whenever “OUT” lamp is on.
Output relay is de-energized whenever “OUT” lamp is on.
Check the “HYS” parameter value if the EX lamp (e) is not turn off when PV (a) is lower than SP (b).
SP
HYS
PV
(A)
(B)
(C)
(A)
(B)
(D)
EXCEEDED
LAMP
OUT
LAMP
lit
off
OUTPUT
RELAY
confirmation
(accepted)
confirmation
(not accepted)
lit
off
Energized
De-energized
OFF
OFF
OFF
Lit
Lit
OFF
Lit
ON
OFF
ON
OFF
Lit
OFF
When the EX lamp (e) is ON but PV (a) is lower than SP (b), the upper display will be in green colour and it shows that the PV is in the
hysteresis area
SP
HYS
PV
(A)
(B)
(C)
EXCEEDED
LAMP
OUT
LAMP
lit
off
OUTPUT
RELAY
confirmation
(accepted)
lit
off
Energized
De-energized
Upper
display
color
(D)
2.3 Working at power on when r.nd is set to 0
(Limit output is de-energized at power on in any cases.)
The output relay is always de-energized (opened) at power-on,even if PV does not exceed SP(A). The output (OUT) display lamp is lit.
If the PV does not exceed SP, after the confirming operation, output relay will be energized (closed) and the output (OUT) display lamp
turns off .
SP
HYS
PV
(A)
(B)
(C)
(A)
(B)
(D)
EXCEEDED
LAMP
OUT
LAMP
lit
off
OUTPUT
RELAY
confirmation
(accepted)
confirmation
(not accepted)
lit
off
Energized
De-energized
OFF
OFF
OFF
Lit
OFF
Lit
OFF
ON
OFF
Lit
OFF
Power
ON
OFF
2.4 Working at power on when r.nd is set to 1
(Limit output is energized at power on when PV doesn’t exceed SP)
The state of output relay is energized (closed) and the output (OUT) display lamp turns off if the PV does not exceed SP at power-on
SP
HYS
PV
(A)
(B)
(D)
(C)
EXCEEDED
LAMP
OUT
LAMP
lit
off
OUTPUT
RELAY
confirmation
(accepted)
lit
off
Energized
De-energized
OFF
OFF
OFF
Lit
ON
OFF
Lit
OFF
Power
ON
OFF
OFF
ON
OFF
2.5 Note about sensor failure (burnout)
Sensor failure shall result in process shutdown for a limit switch; an alarm or process shutdown for a supervisory switch.
Upscale burnout is required for a high limit switch.
Down scale burnout for a low limit switch.
Instrument operativity
