95-8401
2
2.1
The actual effect of H
2
S on an individual depends on
several factors:
1. Concentration level of the exposure
2. Length of time exposed
3. Exposure
frequency
4. Ability to tolerate H
2
S.
Table 1 shows some of the effects of breathing H
2
S
gas.
SPECIFICATIONS
CONTROLLER
OPERATING VOLTAGE—
24 vdc. Can operate in the range of 18 to 32 vdc.
NOTE
When an I.S. barrier is used, the input voltage
(measured at the controller) must be between 23
and 26.6 vdc to ensure proper operation of the
sensor and barrier.
POWER CONSUMPTION (controller only)—
Base model:
0.7 watt nominal, 1.3 watts maxi-
mum (25 ma nominal, 50 ma maxi-
mum at 24 vdc).
Premium model: 1.2 watts nominal, 3.5 watts maxi-
mum (50 ma nominal, 145 ma max-
imum at 24 vdc).
Maximum startup current is 0.6 ampere for 10
milliseconds. Power supplies with fold back current
limiting are not recommended.
MAXIMUM RIPPLE—
Ripple should not exceed 5 volts peak-to-peak. The
sum of dc plus ripple must be
≥
18 vdc and
≤
32 vdc.
TEMPERATURE RANGE—
Operating: +32°F to +140°F (0°C to +60°C)
Storage:
–49°F to +185°F (–45°C to +85°C).
HUMIDITY RANGE—
5 TO 99% R.H., non-condensing.
OPERATING RANGE—
0 to 100, 0 to 50 or 0 to 20 ppm.
ACCURACY—
±3% of full scale over specified temperature range.
SOLID STATE OUTPUTS (Base model only)—
The outputs are open collector transistors with a 100K
resistor from the collector to emitter with the emitter
grounded, rated 100 milliamperes at 32 volts dc
maximum.
RELAY CONTACTS (Premium model only)—
Selectable normally open/normally closed contacts
rated 5 amperes at 30 vdc/250 vac.
CURRENT OUTPUT (Premium model only)—
4 to 20 milliamperes dc current, with a maximum
external loop resistance of 600 ohms at 20 to 32 vdc.
DIMENSIONS—
See Figure 1.
SHIPPING WEIGHT (approximate)—
2.0 pounds (0.9 kilogram).
SYSTEM APPROVAL—
The R8471B Controller, base and premium model in
3U and 4U height, has been tested and approved by
FMA. It can be used with any FMA approved sensing
device capable of generating a 4 to 20 ma input.
FMA approval of the R8471B Controller, however,
does not include or imply approval of input devices
such as sensors or transmitters, or devices connected
to the controller outputs. To maintain FMA system
approval,
all equipment
connected to the controller
must be FMA approved.
NOTE
Ensure sensor hazardous (classified) location
rating is applicable for the intended use.
Concentration Effect
1 ppm
Detectable by odor.
10 ppm
Allowable for 8 hours exposure
(OSHA).
Over 20 ppm
Protective equipment required.
100 ppm
Kills smell in 3 to 15 minutes.
May burn eyes and throat.
200 ppm
Kills smell rapidly. Burns eyes
and
throat.
500 ppm
Victim loses sense of reasoning
and balance. Respiratory distur-
bances in 2 to 15 minutes.
Prompt artificial resuscitation
needed.
700 ppm
Victim becomes unconscious
quickly. Breathing will stop and
death will result if not rescued
promptly. Immediate artificial re-
suscitation
required.
1,000 ppm
Unconscious at once. Permanent
brain damage or death will result
unless rescued promptly.
Table 1—Effects of H
2
S
