Appendix B - Programming Example - Extech Instruments 48VTRR3 Instruction Manual

'06' Process High Alarm with Standby Sequence: Same as the Process High Alarm
but no relay action takes place until the process PV reaches the setpoint for a
second time. Also known as "Startup Inhibit" and is useful for avoiding alarm trips
during startup.
'07' Process Low Alarm with Standby Sequence: Same as the Process Low Alarm
but no relay action takes place until the process PV reaches the setpoint for a
second time. Also known as "Startup Inhibit" and is useful for avoiding alarm trips
during startup.
'08' EVENT ON-Timer: Upon power-up the alarm is de-energized. When the PV = SV
the alarm relay remains de-energized. When the timer counts down to zero, then
the relay energizes. Set the timer at parameter 'time' in Programming Level 1. See
Table IV below.
'09' EVENT OFF-Timer: Upon power-up the alarm relay energizes. When the PV = SV
the alarm relay remains energized. When the timer counts down to zero, then the
relay de-energizes. Set the timer at parameter 'time' in Programming Level 1. See
Table IV below.
'10' SOAK ON-Timer: Upon power-up the alarm relay is de-energized. When the PV =
SV the alarm relay energizes. When the timer counts down to zero the relay de-
energizes. Set the timer at parameter 'time' in Programming Level 1. See Table IV
below.
'11' SOAK OFF-Timer: Upon power-up the alarm relay energizes. When the PV = SV
the alarm relay de-energizes. When the timer counts down to zero the relay
energizes. Set the timer at parameter 'time' in Programming Level 1. See Table IV
below.
A1FU
ALARM RELAY MODE
Setting
8 EVENT ON-TIMER
EVENT OFF-TIMER
9
SOAK ON-TIMER
10
11 SOAK OFF-TIMER
Table IV - EVENT and SOAK Timer Relay States
ON = Alarm Relay energized

APPENDIX B - PROGRAMMING EXAMPLE

Application Example - Maintain an Oven Temperature of 500
The controller monitors the oven temperature via the thermocouple. The controller
compares the actual temperature (PV) to the desired temperature (500
throttles the heater
needed to maintain 500
If the oven temperature
rises too high,
controller's alarm output
can trigger an alert. The
alarm contact can also be
used to switch on/off an
external device such as a
cooling fan.
example, the alarm will
trigger an annunciator at
o
600 F. To perform this
task, refer to the steps
below. The parameters not
listed below are
inconsequential
regard to this example or
they will not appear on the controller display due to the controller configuration.
48VTR English 9/00
Controller
at Power-up
OFF
ON
OFF
ON
OFF = Alarm Relay de-energized
as
o
F.
the
Alarm Output
48VTR
In this
Com pares oven
tem perature to
desired setpoint
and adjusts heater
either
with
Ver. 2.7
When PV=SV
Timer Starts
OFF
ON
ON
OFF
Alarm Annunciator
K Thermocouple input
Control Output
(Adjusts Heater)
12
After Timer
Counts Down
ON
OFF
OFF
ON
o
F
o
setpoint SV) and
Figure 5
(Measures oven temp.)
Oven
Heater