Helios Large Display Pulse Input Batch Controller Instruction Manual
PD2-6310
42
Signal Loss or Loop Break Relay
Operation
The following graph shows the loop break relay
operation for a high alarm relay.
When the meter detects a break in the 4-20 mA
loop, the relay will go to one of the following
selected actions:
1. Turn
On
(Go to alarm condition)
2. Turn
Off
(Go to non-alarm condition)
3. Ignore (Processed as a low signal
condition)
Time Delay Operation
The following graphs show the operation of the
time delay function.
When the signal crosses the set point, the
On
time
delay timer starts and the relay trips when the time
delay has elapsed. If the signal drops below the
set point (high alarm) before the time delay has
elapsed, the
On
time delay timer resets and the
relay does not change state. The same principle
applies to the
Off
time delay.
Note: If “Automatic or Manual (
A-mAn
)” reset
mode is selected, the LED follows the reset
point and not the relay state when the relay
is acknowledged.
Relay Operation Details
Overview
The relays of the controller can serve three roles, as batch control relays for single or multi-stage
batching, as rate, or grand total alarm, or as a sampling relay based on grand total or rate alarm.
These capabilities include front panel alarm status LEDs and 2 or 4 internal relays. The relays used for
batch control (total) are activated when the batching process starts, and deactivate when the batch total is
reached, minus any preclose amount programmed for batch (total) relays after the first.
For an example of batch control operation, see Batch Control Operation Example on page 25.
Typical applications for alarms are low and high flow alarms or grand total limit alarms. Note that rate
alarms are only enabled during a batching process, and deactivate when the processes is stopped.
The relays can also be set for sampling, where the relay will activate for a specific amount of time after a
certain grand total has been reached (ie: 2 second sample relay activation every 100 gallons batched).
There are three basic ways the relays can be used:
1. Batch Control (Total)
2. High or Low Alarms for Rate or Grand Total
3. Sampling (Based on Grand Total and Sample Time)
Relay
LED
Input
Loop Break = Ignore
de-energized
energized
off
on
Relay
LED
Loop Break = Off
Relay
LED
Loop Break = On
Set
Reset
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