Instruction Manual
SRCM Room Pressure Monitor
Installation Instructions
The Setra SRCM Room Pressure Monitor is designed for critical low
differential pressure applications that require stringent pressure monitoring
and alarming. The SRCM can be congured to monitor positive, negative or
neutral pressures in protected environments and hospital isolation rooms per
CDC guidelines. The SRCM is a complete system that includes a backlit color
TFT (480x272 resolution) display with an intuitive graphic user interface which
enables access to pressure, security, calibration, and alarm setup. The touch-
screen display menus guide the user through setup, as well as enabling password
protection. Color changing display and a local audible alarm (with time delay
feature) alert personnel to system status. True differential pressure is displayed
with a resolution of up to .0001”. Setra’s patented very low pressure capacitance
sensor is dead ended and avoids the potential for cross contamination of the
room and reference space as well as eliminating drift that results from fouling of
ow based sensors, which by nature have a ow path connecting the protected
and reference spaces. Additionally there are 2 levels of password protection
available as well as optional BACnet MSTP communications.
1.0 INTENDED USE
The SRCM is designed for indoor use only to monitor critical environments by
providing differential pressure indication. Typically this is between a monitored
room and a reference space such as a corridor or ante room. The unit also
provides monitoring, alarm and communications functions.
Typical Applications:
1. Hospitals – patient isolation and protection rooms, operating suites, intensive
care and emergency rooms.
2. Pharmaceutical, semiconductor, precision manufacturing and clean rooms
3. Laboratories – medical research, BSL (Bio safety labs), radiation, vivarium,
toxic metals and chemicals
1.1 SPECIFICATIONS
Service: Air or nonconductive, nonexplosive gases.
Accuracy: ±0.5% F.S., +/-0.25% FS optional
Operating Temperature Limits: 32 to 120°F (0 to 50°C).
Operating Humidity Limits: 5 min. to 95% max. RH (non-condensing).
Thermal Effects: ±0.03% F.S./ °F (± 0.05% F.S./ °C).
Supply Voltage:
18-30 VAC, 50-60 Hz.
Power Consumption : 5 W for Analog only unit and 10 W forAnalog with
BACnet option.
Analog Inputs: 0-5 Vdc, 0-10Vdc or 4-20 mA loop
Analog Output: Selectable 4-20 mA (2-wire), 0-5 VDC (3-wire), or 0-10 VDC (3-
wire).
Digital Input: Contact closure for door status indication
Loop Resistance (4-20mA output): 500 Ω max..
Electrical Connection: Removable terminal blocks
Pressure Fittings: 3/16” Barbed ttings for 1/8˝ I.D. tubing.
Housing: LEXAN 920/940 Per UL 94 V-0
Mounting: Mounts to customer supplied 3 gang double deep electrical box
Weight approx.: 1.2 lbs
Agency Approval: CE, CSA Class 3631 05 and Class 3631 85 Pollution
Degree 2 and installation Category 2.
Communications: BACnet MSTP ASC, optional, see setra.com for detailed
PICS statement and Objects list.
1.2 SRCM FUNCTION
The SRCM senses very low differential pressure using high accuracy capacitive
sensor technology. The pressure difference for these applications is the difference
in static pressure between a critical environment room and its surrounding
reference area (usually a hallway or another room). Maintaining and monitoring
a static room pressure difference ensures that the critical environment room is
either protected or isolated from a surrounding environment. Protection strategy
requires a net positive room static pressure difference, while isolation requires
a net negative static pressure difference. The SRCM can be programmed to
monitor either positive or negative room static pressure. Low pressure sensing
technology is coupled with multifunctional alarming and simple touch screen
user interface with password security protection. The BACnet communication
option allows the device to communicate with other BACnet devices to allow the
supervisory system to change conguration setups and monitor alarms in an
open network.
User Interface: Touch Screen Display 480 x 272 TFT/WQVGA module, with
LED backlight and 4-wire resistive touch screen
The SRCM indicates the status of the room being monitored using colors.
Color Status
Green Normal, Room Pressure is within alarm limits
Yellow Warning, Door is open (Door input must be enabled) or pressure is
within the alarm deadband
Red Alarm. Room Pressure is outside alarm limits and alarm delay period
has been exceeded.
Blue Use to indicate room is safe to enter.
Audible Feedback: Buzzer will sound when pressure has exceeded alarm
setpoint and alarm delay has timed out. Volume can be adjusted between 1 to 4
in relative sound levels up to the max level. The audible alarm can be disabled.
Quick Room Mode Change: Sometimes the room needs to be changed quickly
from in use (Occupied) to out of use (Standby). This is accomplished by using 2
levels of password protection. The Operator level allows access to change room
modes but no other changes. The Supervisor Level allows full access to all menus.
In Standby mode no alarms are generated even if the pressure is outside limits.
To change modes press the Menu key, press Setup Display key and change room
status to Standby.
2.0 PARTS
2. 1 SRCM INCLUDED PARTS
Parts included in your order:
• SRCM assembly, including factory calibrated differential pressure sensor,
qty 1
• SRCM Faceplate, qty 1
• RPS (Room Static Pressure Sensor) qty 0,1 or 2 (ordered separately)
• 1/4 inch Tubes, Silicone, with springs and barbed
couplings, qty 2
• Mounting screws, 6-32x1/2 Phillips head, qty 5
• Mating Electrical Connectors, Phoenix contact MC plug kit,
qty 1 with 3 green and 2 black connectors
2.2 PARTS REQUIRED AND TO BE SUPPLIED BY INSTALLER
MOUNTING AND WIRING
To mount and install properly, the following components are required:
NOT INCLUDED and required for each SRCM
Triple Gang Double Deep Metal Electrical Box, RACO 697 or Appleton M3-350 or
equivalent: 1
Green grounding screw: 1
Power and signal wiring, as needed
¼” pressure tubing to run from the room(s) to the Pressure Monitor
Transformer, 24 VAC
Door Switch SPDT or SPST, N.O., as needed
Remote Pressure Transducers, as needed
Remote Annunciators, as needed
NOT INCLUDED and required for each SRAN (remote annunciator) and
RPS (room pressure snubber)
Quantity
1 Single Gang Electrical Box
¼” tubing as required to connect between the RPS and the SRCM
Overview of Physical Installation
Field Installation is broken up into 3 phases, “planning”, “rough in” and “nish”.
To make installation easier the SRCM was designed to be mounted in a standard
“off the shelf” electrical box that is readily available at Electrical Supply houses.
During planning decide what functions will be used, such as analog inputs,
analog outputs, door contact inputs, annunciator (SRAN) etc. Order materials
including rough in boxes, wiring, tubing, remote pressure sensors as required.
During “rough in” the eld wiring and plumbing can be run in the walls and routed
between the 3 gang electrical box, the BMS system, door contact switch, remote
sensors (if applicable), power supply, earth ground, etc.
During “nish” phase the pressure tubing will be terminated at the monitor (if
using the internal pressure sensor) and the wiring will be terminated at the
electrical mating connectors (provided).
After the physical installation phase, the unit will be congured for the specic
application through the Touch Screen user Interface.
Note that failure to perform installation as specied here may result in reduced
safety or performance from the unit.
Cleaning and Decontamination: Unit is IP54 rated against dust and liquid
penetration. Exposed surfaces are chemically resistant to vaporized hydrogen
peroxide, formaldehyde, chlorine dioxide, perchlorix acid, sodium, hypochloride
3-6% (bleach), and quaternary ammonia 7% in 1:128 tap water (amonia).
3.0 INSTALLATION
The SRCM is designed to be mounted in a standard triple gang double deep
electrical box RACO 697 or Appleton M3-350 or equivalent.
• A typical SRCM setup consists of a room pressure pick-up, a
reference space pressure pickup and a room pressure monitor
panel, which houses a differential pressure sensor.
• The two pressure pickup ports are installed in single gang
electrical boxes, which are placed in the room walls.
• Standard 1/4" (6 mm) control tubing, maximum 250 feet (76.2
meters) length, is run within the wall from the sensors to the
monitor panel. In some code jurisdictions, the tubing must be in
EMT conduit. Tubing and conduit is provided by others.
NOTE: Secure the triple gang-double deep electrical box to the stud(s) using the mounting hole in the
side of the electrical box (see gure above for mounting hole location). Drive the mounting screws from
the inside of the electrical box into the wall studs to prevent sharp objects protruding into the electrical
box.
3.1 WIRING ELECTRICAL BOX (ROUGH IN)
Wiring must be performed by a licensed Electrician according to local and state
electrical codes.
Use only the knockouts at the back of the rough in box. The front knockouts will
be inaccessible once the room pressure monitor is installed. Strain relief tubing
and wires, and seal box as required.
The SRCM has the option to use the internal pressure sensor or external pressure
transducers (ordered separately). If external pressure transducers are being used,
no tubing needs to be run into the electrical box. The remote pressure transducer(s)
will be separately mounted, plumbed and wired. The analog output of the
transducer(s) will be run to the SRCM. If two rooms are being monitored, you have
the choice to use the internal pressure sensor and an external (remote) transducer
for the second room or two external remote transducers may be used and wired to
the analog inputs in the back of the SRCM.
Layout the system in terms of wiring:
• All wires are 16 AWG max.
• Power 24 VAC, 10 VA.
• Annunciator/relay, remote alarm wiring if being used
• Analog output, 0-5 Vdc or 0-10 Vdc or 4-20 mA.
• Analog Input wiring, there are 2 analog inputs that can be used to bring signals
from remote pressure transducers
• Digital Input, the digital input can be used as a door status indication, these would
be wired to a door switch mounted in the door jamb.
3.2 BACnet Wiring
BACnet MS/TP network, if that option has been ordered. BACnet suggested
wiring is 22 AWG stranded wire in a shielded cable, a +,-, Gnd and shield
should be run. This can be 2 twisted pairs with a separate cable shield. One
twisted pair is used for communications, the second twisted pair can be used
for communications ground and the shield wire can be connected to the other
device shield wires.
BACnet hardware is implemented as isolated RS485. Wire to Connector COMM,
labeled RS485. Connect TX line to B (+), RX to A (-) and ground wires to GND.
Connect shields together with wire nut.
Hardware conguration is done using a ve position dip switch located in the upper
right hand section of the PCB as well as through the touch screen interface.
Switch Position Function
1 Network Setup Enable
2 Not Connected (Not Used)
3 Pull Up Resistor
4 Termination Resistor
5 Pull Down Resistor
Use a small at blade screwdriver or pen to push the switch to the right to turn the
function on, otherwise it is off. Set Position 1 to on (right) to enable network setup.
Complete the setup by using the Network Setup Screen.
If the unit will be at the end of the line, the pull up resistor can be enabled by
pushing position 3 to on.
The termination resistor can be inserted by pushing position 4 switch on. The pull
down resistor can be enabled by turning position 5 to on.
If Pull UP, Pull Down or Termination Resistors are not used, disable them by
3 gang electrical box rough wiring and plumbing