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- Microprocessor based Addressable modules
- Discrete 4-20mA output
- Three (3) Programmable alarm relays
- RS-485 MODBUS ® RTU Serial Communication
- PLC and SCADA Compatibility
- Alarm Status LED Indicators
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Description
Model PT900 Series
Control module is a microprocessor-based single channel
toxic or combustible gas control module designed for
use with Pem-Tech's gas sensors. The control module
provides digital display, 4-20mA analog output and programmable
alarm relay contacts.
The low power RISC based microprocessor
allows all the alarm levels and control module address
programmed via switches on the front panel. The bright
LED display indicates the gas concentration. Also features
amber and red LED indicators for alarm status. One of
the safety features is a flashing digital display when
the control module is in alarm bypass mode. The flashing
display is an indication to the personnel in the control
room about the alarm bypass status.
Each control module has RS-485 MODBUS ®
RTU serial communication compatible with PLC's, SCADA,
and DCS systems. The module provides complete status
like current gas concentration, sensor calibration and
current alarm status. The alarm levels can also be accessed
and programmed via MODBUS ®.
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Model PT900 Series Gas Control
Module
Specifications |
Electrical Classification
19" Rackmount. Non-Hazardous area
Front Panel Indicators
2 Bright LED digital display
4 each Alarm LED Indicators:
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Amber for Low Alarm
Red for High, High-High and fault |
- Flashing digital display if module in alarm bypass mode.
Test & Safety Features
Displays programmed alarm levels
and alarm
with flashing alarm LED indicators at unit
power up to check the integrity of display and
LED indicators
Operating Temperature
-40°F to +158°F (-40°C to +70°C)
Operating Humidity
5% to 100% RH, non-condensing
Mechanical Specifications
Height: 5 ¼ inches (133 mm)
Width: 1 ¼ inches (32 mm)
Depth: 8 inches (203 mm)
Approvals
ABS Type approved
ABS Rules: 1-1-4/3.7, 4-8-3/tbl 2
4-8-3/1.7
Warranty
Two years
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Input Power
14-28 VDC. 24 VDC nominal
Power Consumption
160mA @ 24 VDC including gas sensor and
control module
Alarm Relays
Low, High & High-High alarm relays.
Fully programmable zero to full scale range.
Latching or non-latching, normally open or
normally-closed contacts.
Relay Ratings
SPDT Form "C" type Relay contacts
5 Amps @ 250 VAC or 30 VDC
Analog Output
Linear 4-20mA (300 Ohms max. load)
2.0 mA - When sensor in Calibration mode
< 1.0 mA - Sensor malfunction
RS-485 Interface
MODBUS ® RTU Compatible with PLC's,
SCADA and DCS systems.
MODBUS ® registers defined in the control
module are:
- Gas concentrations
- Current alarm status
- Sensor in calibration mode
- Currently programmed alarm levels
Alarms can be Reset and Bypassed via MODBUS ® link. Alarm
levels can also be reprogrammed via MODBUS ®.
Cable Requirement
3 wire shielded cable. Max loop resistance of
20 Ohms @ 24 VDC nominal between the
sensor and PT900 Control module
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