Sensors; Overview; Internal Sensors; Temperature Offset - Geist GRSE Series Instruction Manual

Sensors

Overview

All internal sensors are measured every 5 seconds. External sensors are measured every 10 to
30 seconds, depending on the number of devices connected.
GRSE Series units will provide useful trend analysis data. While all values are not absolute in
relation to a known unit, trend analysis of the data allows users to view changes and draw
useful conclusions about what is happening over time in the monitored environment.

Internal Sensors

The GRSE Series units contain the following onboard sensors:
 Temperature: Measures temperature and can be displayed in °C or °F. The accuracy is ±1
°F from -50 °F to 185 °F. Note: This sensor may be heated by internal circuitry in the unit;
a temperature offset is available to re-calibrate.
 Relative Humidity: Measures the percent of Relative Humidity ±5%.
 Airflow: Measures airflow is a unit-less value.
temperature drop of a heated element in open air vs. still air. This value can be set to 20 in
any airflow condition using Telnet.
changes in temperature can affect the accuracy of this sensor.
affected by temperature.
 Light Level: Measures Light Level as a unit-less reading of 0 to 99.
 Sound Level: Measures Sound Level as a unit-less reading of 0 to 99.
 IO-1: Scales 0 to 5 Vdc input to 0-99, dry contacts may be used.
 IO-2: Scales 0 to 5 Vdc input to 0-99, dry contacts may be used.
 IO-3: Scales 0 to 5 Vdc input to 0-99, dry contacts may be used.

Temperature Offset

The internal temperature sensor is pre-calibrated at the factory and the values reported by this
sensor are accurate. However, due to low airflow and normal board heating, the temperature
sensor may read a few degrees higher than any external sensors that are attached.
counteract this, an offset of up to -7 °C or °F is configurable on the Display Page.

I/O Sensors

The GRSE Series units come equipped with three I/O ports for connecting additional external
sensors such as Water and Door Sensors. The three ports are designed to accept a 0-5 Vdc
analog input; alternatively, an internal 100K pull up resistor to 5 V allows for the use of dry
contacts. The I/O port input is converted to a digital number ranging from 0 to 99 and is
displayed on the Sensors page. Unused I/O ports will display a value of 99.
Water sensors act as conductivity bridges. Moisture across the contacts causes the value to
drop. Door switches can be wired in a serial connection; if the chain is broken the entire group
is classified as open. The limiting factor on the I/O ports is the length of the wire, found to be
around 400'.
GM1089
A reading of 0 to 99 is based on the
Note: Due to the method of measurement, sharp
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Sensor data collected by the
Sensitivity will also be
Revision Date: 5/8/2012
To