OVERVIEW
Pem-Tech model PT920 is a microprocessor based single channel monitor
that utilizes the latest digital design techniques in instrumentation. The
monitor uses an 8-bit high speed RISC processor with a highly accurate
analog to digital logic. The controller module receives the signal from
remote gas transmitters and displays the gas concentration. The 24VDC
power to the control module is supplied by the common bus on the back
plane (main connection board). The power to the remote sensor connected
to the module is routed through a miniature fuse on the module.
Standard features are:
•
Displays current gas concentration on two (2) Digit Bright LED
display ( 3 digits display for Oxygen deficiency )
•
Low, High, & High-High fully programmable alarm relay contacts.
•
Alarms programmable via switches on the front panel
•
Sensor Malfunction relay contact.
•
Visual alarm indicators on the front panel.
•
Alarm RESET and BYPASS switch.
•
Optional RS485 Serial Communication for Remote data display
•
Master Alarm Reset on the main rack assembly to Reset Alarms.
Programmable Relays
Each control module can be programmed for 3 distinct alarm levels. The
alarm levels can be easily programmed using Pushbutton switch provided
on the front panel of the control module. The alarm relays on the main
connection board are configured to have discrete Low level gas alarm for
Toxic (H2S) and combustibles (LEL) gases. Also present on the main
connection board are common High and Hi-Hi alarm relay contacts.
Below each control module there is a 2-pin jumper to select the module for
Toxic or Combustible type. Proper selection of this jumper will enable the
module to properly activate the low level alarm relay.
Also present is a common Sensor Malfunction alarm relay.
All relays are Form “C” type. Low and High alarm relays are rated
10Amps each while Hi-Hi and Malfunction are rated 5 Amps each.
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