PEMTECH PT900-12R User manual

MODEL PT900-12R
12 Channel Gas Monitor & Controller
19” Rack mount
Operator’s
Manual
Revision 3.1
November 2003
Pem-Tech, Inc.
Houston, Texas
U.S.A.

2
NOTICE
PEM-TECH INCORPORATED SHALL NOT BE LIABLE FOR TECHNICAL
OR EDITORIAL ERRORS OR OMISSIONS MADE HEREIN, NOR FOR
INCIDENTAL OR CONSEQUENTIAL DAMAGES RESULTING FROM
THE FURNISHING, PERFORMANCE, OR USE OF THIS MATERIAL.
LIMITED WARRANTY
Pem-Tech, Incorporated warrants all the equipment to be free from defects in
workmanship and material. The products will operate in conformance with the
published specifications when subjected to intended and proper usage for the period
of one (1) year from the date of shipment.
The warranty provides only the benefits specified and does not cover defects which
result from acts beyond the control of PEM-TECH including, but not limited to:
damage by accident, negligence, tampering, or failure to operate in accordance with
the procedures outlined in the Operations Manual. PEM-TECH’s liability under no
circumstances will exceed replacement of the unit claimed to be defective.
Tampering with the equipment and altering it for uses other than the intended use or
replacement of parts not supplied by the company, shall immediately void and cancel
all the warranties with respect to the affected products.
The warranties specified herein are in lieu of any and all other warranties, express or
implied. In no event, whether as a result of breach of warranty or alleged negligence,
shall PEM-TECH be liable for special or consequential damages, including, but not
limited to, loss of profits or revenue, loss of equipment or down time costs.

3
SERVICE POLICY
Pem-Tech has service facility at the factory. For all the repairs contact at our toll free
number 1-800-379-3894 or visit our website www.pem-tech.com
For all repairs call us for a Return Material Authorization number (RMA). Inform us
briefly the nature of the problem and obtain shipping address. Properly pack the
equipment before shipping. Also include your complete shipping address and contact
name and phone number.
For non-warranty repairs you must provide the limit to repair costs. State if a quote
for repair cost is required before you can authorize the repair cost. For this an
additional charge may be applicable.
NOTE:
1. For all the repairs under warranty, serial number must be legible on the items
being repaired.
2. Shipping point is FOB Houston.

4
TABLE OF CONTENTS
Specifications 5
Specifications for PT900-12R Rack assembly 5
Specifications for Model PT902M Control monitor 6
Overview 7
Programmable Relays 7
Figure 1. PT902M Control module Front Panel diagram 8
Installation and Startup 9
Figure 2. PT900-12R Rack Assembly 9
Setting Control module Address / ID 10
Modifying Module Address 10
AC or DC power Input 11
Connecting sensors to monitor 11
Alarm wiring 11
Figure 3. System Overview drawing, 12
User termination, control modules in
Rack assembly
Figure 4. Sensor and alarm wiring diagram 13
Figure 5. Wiring auxiliary relay board for common 14
Alarm contacts
Startup 15
Apply Power 15
Normal Operation and alarms
Normal Operation 16
Alarms 16
Alarm Reset 16
Alarm Bypass 16
Programming Alarms 17
Programming Alarm Levels 18
Setting alarms as Latching or Non-Latching 18
Setting alarm contacts as Normally Open or 19
Normally Closed
Figure 6. PT902M Control Monitor circuit diagram 20
Malfunction Condition 22
Parts List 23

5
SPECIFICATIONS
For PT900-12 Rack Assembly
MOUNTING: Standard 19” Rack mount
OPERATING -40 °F to +170 °F.
TEMPERATURE
POWER INPUT: 24 VDC
HUMIDITY: 0 to 100% non condensing
AUXILIARY ALARM 4 Common alarm relays
RELAYS (Optional) Form “C” type rated 10Amps
TERMINATIONS Terminal blocks for sensor and alarm connections
for wire size 16-22 AWG

6
SPECIFICATIONS
For PT902M Control Module
Display Range: 0 to 99
Input Signal: 4-20mA (Optional 1-5 VDC)
Analog Output: Linear 4-20mA output. < 1.5mA when remote
sensor in malfunction.
Maximum of 350 Ohms loop resistance.
Relay Ratings: 4 each Form “C” type relay contacts
Rated 5 Amps each
Low, High, High-High field programmable alarm
levels, Latching or non-latching, Normally open or
Normally Closed contacts
Fault Relay: Malfunction relay activated when remote sensor in
fail. Programmable as Normally open or normally
closed contacts
Visual Indicators: 4 Bright LEDs on the front panel to indicate alarm
status. Amber LED for Low Alarm
Red LEDs for High and High-High and
Malfunction Alarm
Power Input: 24 VDC Nominal (18-28 VDC)
Power is supplied to remote sensor & transmitter
through a 2 Amp miniature fuse
Power Consumption: < 1.2 Watt normal operation for each control
module. Max of 2.1 watt with all relays active.

7
OVERVIEW
Pem-Tech model PT902M 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 control module receives signal from the remote gas
transmitter, displays the gas concentration, and generates 4-20mA analog
output. The discrete outputs from 4 alarm relays can be used to activate
external alarm devices. Each control module is connected to a common
24VDC supply at the back of the 19” Rack assembly. The module provides
power to the remote sensor & transmitters via 2Amp miniature fuse.
Standard features are:
•Displays current gas concentration on two (2) Digit Bright LED display .
•Provides a 4-20mA output.
•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.
•RS485 Serial Communication for Remote data display
•Master Alarm Reset connection for Remote alarm Reset Switch.
Programmable Relays
Each control module has three (3) programmable relays for Low, High, and
High-High alarms. The alarm relay set points can be programmed via
pushbutton switch provided on the front panel. Sensor and alarm
terminations are provided on the rear of the 19” Rack assembly. A common
terminal is also provided for sensor malfunction (or fault). This terminal is
common to the Fail relays on all the control modules in the system. The
terminal can, therefore, be used as dry contact for a local audible alarm. In
addition jumper blocks are also provided to common all the relays on the
control modules in order to use an auxiliary relays.
For further details refer to section on Programming alarm Relays later in this
manual.

8
ALARMS
NORMAL
BYPASS
PEM−TECH, INC.
LOW
HIGH
HI−HI
MALF
MODEL PT 950
MONITOR
HOUSTON, TEXAS
Di
g
ital Displa
y
Visual Alarm LED indicators
Alarm B
yp
ass Switch
Pushbutton switch
(Alarm Reset & Adjust)
Captive Screw
Handle
Figure 1. PT902M Control Module
Model PT902M
Monitor

9
INSTALLATION AND START UP
Model PT902M Control Module is suitable to mount in a PT900-12R Series
Rack assembly with card guides for main circuit board mounting. On the
front panel a captive screw is provided to secure the control module to the
rack. Do not use excessive force to tighten the screw. Also a handle is
provided to facilitate for easy insertion and removal of the module from the
rack assembly.
PT902M Control module can be connected to any PT205 and PT295 Series
sensor & transmitter. Refer to figure 4 for sensor wiring connections.
Figure 2. PT902M Series Control Modules in a standard 19” Rack assembly.

10
Setting Unit Address ID
***** Skip this section if RS485 or Remote annunciator are not used ******
On PT900-12R Termination board two jumper J1 and J2 located on upper left
corner are used for extended module address. Proper jumpers are requied if
remote annunciators are connected or RS485 Port is used. These jumpers
assign a unique address to a rack with control modules. Two jumper selection
can provide up 48 distinct control module addresses in four (4) PT900-12R
monitors. The following table gives jumper selections for proper addresses.
J1 J2 Monitor Rack # Module / Channel #
OFF OFF 1 CH1 – CH12
ON OFF 2 CH13 – CH24
OFF ON 3 CH25 – CH36
ON ON 4 CH37 – CH48
Modifying Control Module Address:
The control module address can be changed from its default address.
Remember that all control modules in the control panel must have sequential
and distinct addresses to communicate properly with the remote annunciator.
To change the module address follow the steps below.
1. Position the toggle switch on the front panel of the control module to
“NORMAL”.
2. Press and hold the pushbutton switch for few seconds and the module will
display the current address. To change the address push and hold the
switch until the desired address is displayed. The address rolls over to 0
after 99.
3. Release the switch. The module saves the address into its non-volatile
memory. The address is retained until modified again.

11
DC Power Input
A two (2) pin wire terminal is provided on the rear termination board for DC
power input. The terminal is clearly labeled DC IN. Connect the external DC
power to this terminal. Nominal DC power is 24 Volts
Refer to figure 3 for the location of the DC IN terminal.
Connecting Sensors to the Monitor
Three (3) pin screw type terminals are provided on the termination board for
remote sensor connection. The terminals are labeled as SENSOR and each pin
is identified as +, -, & E for sensor DC supply, ground, and signal
respectively. The DC is supplied to the sensor by the control module. The
supply is fused through a 2 amp miniature fuse on the control module.
Each remote sensor should be connected by a 3 conductor shielded cable. See
figure 4 for remote sensor connection.
Alarm Wiring
Figure 4 shows a typical wiring diagram for connecting alarm devices to relay
contacts on the control module. Note that contacts are dry or potential free
contacts. Refer to the wiring details provided by the manufacturer of alarm
devices.
Figure 4 shows the wiring of alarm devices to the relay contacts of a control
module. Similar wiring procedure should be followed if the auxiliary relay
board is used to connect to the alarm devices.
In order to use the auxiliary relay board all jumpers JMP-1 through JMP-11 are
installed. The jumpers are used to connect each contact of the alarms (Low, Hi
& Hi-Hi) to common auxiliary alarms. The relay on the Auxiliary relay board
will be energized if the corresponding alarm relay is activated on any of the 12
control modules in the rack assembly.
Refer to figure 5.

12
CH12CH11CH10CH9CH8CH7CH6CH5CH4CH3CH2CH1
JMP11JMP10JMP9JMP8JMP7JMP6JMP5JMP4JMP3JMP2JMP1
DCIN
RESET
MALF
EXT.
+
−
RS485
−T
+T
SHLD
GND
OUT
COM
SENSOR 4−20 HI−HI HIGH LOW
E
−
+
+
−
OUT
COM
OUT
COM
OUT
COM
+
−
ANALOGOUTPUT
4−20mA
(OPTIONAL)
E
+
−
3CONDUCTORSHIELDEDCABLE
EACHSENSORCONNECTEDSEPERATELY
TOTHECONTROLMONITORMODULE
ADDRESSID
JUMPERS
+24VDCSUPPLY
FROMPOWERSUPPLY
REMOTEALARM
RESET
(FORDRYCONTACTSWITCH)
SINGLEPAIRTWISTED
SHILEDEDCABLE
FORDATACOMMUNICATION
MAXLENGTH4000FEET
DRYALARM
SENSORMALFUNCTION
RELAYCONTACTS
DRYALARM
CONTACTSFOR
INDIVIDUAL
CONTROLMODULE
CONNECTION
JUMPERLINKSFROM1THRU11
FORCOMMONALARMCONTACTS
REFERTODRAWINGB2000xxxx
FOREXTERNALALARMDEVICE
WIRING
HI−HI
HIGH
LOW
PT900SERIESRACKMOUNTMONITOR
TERMINATIONBOARDASSEMBLY
AUX RELAY PORT
RIBBONCABLECONNECTOR
TOAUXILIARYRELAYBOARDASSEMBLY
DATE:03/20/02
B20031021.0
1OF1
TERMINATIONBOARD
MODELPT902RACKMOUNTCONTROLMONITOR
Figure 3. User termination – PT900-12R Rack assembly

13
Figure 4. Remote Sensor connection.
Alarm wiring to control modules.

14
Figure 5. Wiring Auxiliary relay board for common alarm contacts
SCALESHEET
DWGNO.REV
REVISIONS
ZONEREVDESCRIPTIONDATEAPPROVED
DATE:
APPROVALS
PROJECT:
HOUSTON,TEXAS
ALARM−1
NO
COM
NC
ALARM−2
COM
NC
NO
ALARM−3
COM
NC
NO
ALARM−4
COM
NC
NO
RELAY 1
RELAY 2
RELAY 3
RELAY 4
RIBBONCABLE
CONNECTTOPT900−12R
TERMINATIONBOARD
TO AUX.
RELAYS
PT900−12R
TERMINATIONBOARD
AUXILIARYRELAYBOARDASSEMBLY
PARTNUMBER:S−760
ALARM−1
DEVICE
DEVICE
ALARM−2
RETURN
+V
DEVICE
ALARM−3
+VRETURN
+VRETURN
POWERSOURCEFOR
ALARMDEVICES
ACORDC
+V
SUPPLY
SUPPLY
RETURN
JUMP/WIREALL"COM"
TERMINALSTOGETHER&
CONNECTTOSUPPLYRETURN
FORALARMDEVICES
ALARMRELAYS
CONTACTSRATED
10AMPSEACH
NOTE:
ALARM−1,ALARM−2,&ALARM−3
CORRESPONDSTOLOW,HIGH,&
HI−HIALARMSONTHE
CONTROLMODULE
AUXILIARYRELAYBDASSEMBLY
WIRINGEXTERNALALARMDEVICES
B2003104
2.0
RM
7/10/031OF1

15
Start Up
Complete the following procedures for the normal unit operation.
1. Complete the mounting and wiring procedures described in earlier
sections.
2. Follow gas sensor & transmitter operation manual for proper wiring of
sensors with the monitor.
3. Verify all the wiring connections to be correct and secure.
4. Verify that all the control modules are secured with captive screws on the
front panel.
Apply Power
Verify all the sensor and alarm relays connections. Apply the DC power and
then check the following conditions.
1. All the installed control modules will display their corresponding channel
number on the display (channel 1 thru 12). For example the control
module in the slot 1 will display 01, module in slot 2 will display 02 and so
on. The channel number will rapidly flash for few seconds.
2. Each control module will then display low, high and High-High alarm set
points. The visual alarm LED indicator will be lit while the unit displays
the alarm set point.
3. The control module goes into normal operation and starts reading signal
from the sensor / transmitter.
Note: If a control module display remains blank upon power up or the
channel number flashing is incorrect then remove the control module and
reinsert into card guides in order to properly snap into the card edge
connectors on the termination board.

16
NORMAL OPERATION AND ALARMS
Normal Operation
During normal operation each control module will display the current gas
concentration on the display. If the sensor reading is below alarm level then
all the alarm relays and the visual alarm LED indicators on the front panel
should be off.
Alarms
Each PT902M control monitor is equipped with four (4) alarm relay contacts.
The alarms are labeled as Low, High & High-High. The fourth alarm contacts
is for sensor malfunction. The monitor activates the alarm relays when the
sensor reading exceeds the programmed alarm set point. Also LEDs on the
front panel will also light up for visual alarm indication.
Standard alarm set points are programmed at the factory before shipment. The
user must verify the alarm set points and make changes if desired. Refer to
section on Programming Alarm Set points. See table 1 for range and default
alarm levels for few of the PT902M Control monitor modules.
Alarm Reset
Once the gas concentration has dropped below the alarm level the relay will
deactivate itself. However, this is true only of the relay is configured as non-
latching (NL). If the relay is configured latching then it must be deactivated
manually. To deactivate the latching alarm press and hold the push button on
the front panel until relays and LED indicators turn off. A master alarm reset
switch on the control module rack assembly can also be used to reset the
alarms. This will reset alarms on all control modules.
Note: If the gas concentration continues to be higher than the programmed alarm set
point the alarm will be activated again.

17
Alarm Bypass
In the Alarm Bypass mode the monitor will not activate the alarm relays if any
of the sensor reading exceeds the programmed alarm level. However, the
visual alarm LED indicators will be activated.
To put the alarms in bypass mode move the ALARM toggle switch on the
front panel of the control module to BYPASS position. If the gas reading is
above alarm level the visual alarm LED indicators will flash once every second
indicating that the alarms are in bypass mode. The switch must be returned to
NORMAL to end alarm bypass mode and for normal operation.
Programming Alarms
Alarm levels must be programmed in order to activate the dry relay contacts
on the main control board. Alarm levels can be set anywhere between 0 and
the full scale of the sensor. Alarm relays can also be selected as Latching or
non-latching type. Also jumpers on the control module can be selected to
program the relay contacts to be Normally Open or Normally Closed.
If any alarm level is set to 00 then that relay will not be activated any time
during normal operation.
Note
•Non-Latching alarm is self resetting. Alarm relay will be de-activated if gas
concentration falls below the alarm set point.
•Latching alarm on the other hand will not self reset if concentration falls below
alarm set point. The alarm relays must be manually reset by pressing the RESET
switch on the front panel

18
Table I. Range and factory alarm level settings.
Control Module Range Low Alarm
Level
Hi Alarm
Level
Hi-Hi Alarm
Level
Hydrogen Sulfide (H2S) 100 ppm 10 ppm (NL) 15 ppm (NL) 20 ppm (NL)
Combustible (LEL) 100 % 10 % (NL) 20 % (NL) 30% (NL)
Oxygen (O2) 25 % 17 % (NL) 23 %(NL) 24% (NL)
Sulfur Dioxide (SO2) 50 ppm 5 ppm (NL) 15 ppm (NL) 20 ppm (NL)
Carbon Monoxide (CO) 100 ppm 10 ppm (NL) 20 ppm (NL) 50 ppm (NL)
Nitrogen Dioxide (NO2) 20 ppm 5 ppm (NL) 15 ppm (NL) 20 ppm (NL)
Note that for Oxygen Low Alarm is activated on the depleting oxygen level. That is
Low alarm relay is activated when the oxygen concentration falls below the
programmed low alarm level.

19
Programming Alarm Levels
1. Move the toggle switch on the front panel to BYPASS position.
2. Press and hold the pushbutton switch (above the toggle switch) until the
Low alarm LED starts flashing. Release the switch.
3. While the LED is flashing the display will show the current alarm level. To
change the level press and hold the pushbutton switch until the display
reads the desired alarm setting. The alarm level can be adjusted between 0
and the full scale of the sensor. For example, for H2S or LEL the alarm level
can be set between 0 and 99. If the desired alarm level is below current
settings press and hold the switch. The displayed alarm level will start over
from 0 after 99.
4. Release the switch when alarm level set.
5. About five (5) seconds after the switch has been released the Low alarm
LED will be turned off. Low alarm level is set. Now High alarm LED starts
flashing and the display will show the High alarm level. The monitor is
ready for High alarm level. Repeat steps 3 and 4 to set High and High-
High alarm levels.
6. After setting High-High alarm level the monitor will return to normal
operation.
Setting Alarm as Latching or Non-Latching
The alarms can be set as latching or Non-Latching by setting the Dip-Switch
located on upper left corner of the control module. See figure 6. The dip-
switch is labeled as Relays with arrow indicating the switch selection for
latching or non-latching. Position 1 of the Dip-switch is for Low alarm ,
position 2 is for High alarm and position 3 for High-High alarm. Position 4 is
not used for standard application and is reserved for custom application or
future use.
To set the alarm as latching move the dip-switch up or move the dip switch
down for non-latching alarms.
The dip-switch positions in the diagram below shows Low and High alarm
configured as non-latching and High-High alarm set as latching

20
Setting alarm contacts as Normally Open or Normally Closed
To set the alarm contacts as normally open or normally closed set the jumpers
for each relay located right above the relay on the control module. See figure
6. Each jumper is a 3 pin header with a mating connector to connect any two
of the three pins. To set the contact type set the jumpers as show below.
NO NC NO NC
Jump Pin 2 and 3 for
Normally closed contacts
Jump Pin 1 and 2 for
Normally Open contacts
RELAYS
LATCHING
NON−LATHING 123 4