Product manual

Model HC2S3 Temperature and Relative

Humidity Probe

1. General Description

The HC2S3 is a digital probe with 0 to 1 V linear output signals for

temperature and humidity, and a UART serial interface. The voltage signals

can be measured with two single-ended or two differential inputs on the

datalogger. A special Rotronic cable and the SDM-SIO1 Serial I/O Module or

MD485 RS-485 Interface is required to interface with the UART as described

in Appendix B.

The D/A converter used to generate the analog output signals has 16-bit

resolution. The default configuration is for temperature -40° to +60°C, and

0 - 100% relative humidity. Temperature range and other default settings can

be changed as described in Appendix A.

A cable ordered through CSI for the HC2S3 includes an internal voltage

regulator that applies 3.3 V to the probe from a 5 to 24 V power source. 12V

power is recommended for use with CSI dataloggers. Where minimizing

power use is important, power can be switched on and off for the measurement

provided there is a 3-second warm-up delay. Switching power avoids the

constant current flow through datalogger ground, which can affect the

accuracy of low level single-ended voltage measurements, primarily with older

dataloggers such as the 21X.

Probes are polarity protected by the keyed connector and a diode in the

connector interface provided with the CSI cable.

CSI offers two filters:

Polyethylene filter: Default filter, protection against fine dust

particles, no water absorption or retention, good response time.

Teflon filter: Recommended for marine environments, slower

response time than the polyethylene filter, ordered separately.

Lead length for the HC2S3 is specified when the probe is ordered with the

suffix -LXX, where XX is the cable length in feet; for example, HC2S3-L11

for a probe with an 11 foot cable. Table 1-1 gives the recommended lengths

for various mounts.

TABLE 1-1. Recommended Lead Lengths

2 m Height Atop a tripod or tower via a 2 ft crossarm such as the CM202

Mast/Leg CM202 CM6 CM10 CM110 CM115 CM120 UT10 UT20 UT30

9' 11' 11' 14' 14' 19' 24' 14' 24' 37'

Note: Add two feet to the cable length if you are mounting the enclosure on the leg base of a CM106 or CM110

series tripod.