NORMAL OPERATION
Part. No. 2400M2501_6 Touchpoint Pro
119 Technical Handbook
14.2.1 Using the STEL Alarm
Use the short term exposure limit (STEL) feature to indicate if a gas sensor is detecting an average level of gas that will
result in a hazardous situation.
The STEL feature continuously calculates the average gas level over time using a user selectable time period (STEL Time
Interval). An alarm will be indicated if the average gas level exceeds a user selected limit (STEL Alarm Level) within the
STEL Time Interval.
STEL alarm functionality is normally associated with personal gas detection equipment where it will give information about
an individual’s exposure to a hazard. As TPPR and associated sensors are fixed equipment, the user must consider how the
STEL feature is to be used as it is the sensor and not an individual that is exposed to gas.
The STEL function becomes active and starts monitoring the average gas level when the STEL alarm has been enabled and
the input module returns to its normal state. If the STEL alarm had already been enabled prior to TPPR being powered
down, then the STEL function becomes active when TPPR is powered up.
14.2.2 Assigning the STEL Alarm to an Output Relay
To assign an output relay to an input channel’s STEL alarm, navigate to the cause and effect (C&E) matrix for the required
relay and select Alarm 1 (AL1) for the input channel as shown in the figure below.
Threshold Alarm 1 and STEL share the output relay. If the channel is programmed for threshold levels then AL1 selection is
used for the first threshold alarm and STEL may not be assigned to a relay. Similarly, if the channel is programmed for
STEL, AL1 is reserved for STEL and may not be assigned to a threshold alarm.
This relay will also be assigned to the required inputs for Threshold alarm 1.
14.3 Rate Alarm
Rate Alarms can be setup to trigger when a gas concentration changes quickly. An alarm may be triggered by a rising or
falling gas level even though the gas has not reached a threshold level. The extent of change and the time period are
programmable.
14.4 Relay Activated Outputs
TPPR has the ability to automatically operate relay controlled outputs when an alarm is triggered. These outputs are
determined during commissioning and may be used to control any or all of these:
Light Stacks and Sirens
Automated Emergency Services alerts
Actuator controlled vents, valves and switches (i.e. power-breaking, purging, sprinkling or flooding)
Exit door release
Entry Barrier closing
Select AL1 to assign this relay to the selected inputs STEL alarm. Note that this relay will
also be assigned to the selected inputs alarm 1 threshold.
To Next Page
Loading...
Need help?
General
