PEMTECH PT920-16SS User manual

MODEL PT920-16SS
16 CHANNEL
GAS MONITOR & CONTROLLER
Operator’s
Manual
Revision 2.0
May 2008
Pem-Tech, Inc.
Houston, Texas
U.S.A.

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.
2

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.
3

TABLE OF CONTENTS
Specifications 5
Specifications for PT920-16 Rack assembly 5
Specifications for Model PT920 Series Control monitor 6
Overview 7
Programmable Relays 7
Figure 1. PT920 Control module Front Panel diagram 8
Installation and Startup 9
Figure 2. PT920-16SS Enclosure dimension 9
AC / DC Unit Power Up 10
Figure 3. System Overview drawing, 11
User termination, control modules in
Rack assembly
Connecting sensors to monitor 12
Connecting 4-20mA Gas Transmitter 12
Connecting Proximity Sensors 13
Figure 6. Typical sensor interface to Main connection 14
Board
Auxiliary 10-Amps alarm relay board assembly 15
Figure 7. Auxiliary alarm board interface to PT920 15
Figure 8. Jumper settings for Control Module type 16
Wiring Audio / Visual Alarms 17
Figure 9. Wiring diagram for Audio/Visual alarms 17
Startup 18
Apply Power 18
Setting Control module ID / Address 19
Normal Operation and alarms
Normal Operation 20
Alarms 21
Alarm Reset 21
Alarm Bypass 22
Programming Alarms 22
Programming Alarm Levels 23
Setting alarms as Latching or Non-Latching 24
Figure 10. PT920 Control Module diagram 25
Malfunction Condition 26
PartsList 27
4

SPECIFICATIONS
For PT920 Rack Assembly with Power Supply
MOUNTING: Wall or Panel Mount
ENCLOSURE: NEMA 4X Stainless Steel Enclosure with clear
window
DIMENSIONS: 19”H x 16”W x 8”D
WEIGHT: 45 Lbs.
OPERATING -40 °F to +170 °F. (-20 °C to +70 °C.)
TEMPERATURE
POWER INPUT: 110-220 VAC or 24 VDC
HUMIDITY: 0 to 100% non condensing
ALARM RELAYS 4 alarm relays. Form “C” type rated 10 Amps
1 relay for Hi-Hi and 1 for Malfunction each
rated 5 Amps
TERMINATIONS Terminal blocks for sensor and alarm
connections for wire size 16-22 AWG
ALARM RESET Master alarm Reset switch to Reset Alarms
SWITCH on all control modules
5

SPECIFICATIONS
For PT920 Control Module
Display Range: 0 to 99 for Toxic and Combustibles
0 to 25.0 % for Oxygen deficiency ( 3 Digit
Display)
Input Signal: 4-20mA ( for Gas Control Module)
Discrete ( For Status Input Module)
Relay Ratings: 4 each Form C type relay contacts
Rated 5 Amps each
Low, High, High-High, and Malfunction
Field programmable alarm levels, Latching or
non-latching, Normally open or Normally
Closed contact
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 power input. Power is supplied
to remote sensor & transmitter through a 2
Amp miniature fuse
Power Consumption: < 1 Watt normal operation for each control
module. Max of 2.4 watt with all relays active.
Alarm Reset Pushbutton switch on front panel to Reset
Alarms
Alarm Bypass Toggle Switch to Bypass / Inhibit Alarm relays
6

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.
7

Figure 1: PT920 Series Control Module
8
MODEL PT 920
BYPASS
ALARMS
NORMAL
HOUSTON, TX
MALF
RESET
HIGH
HI−HI
LOW
LEDs FOR VISUAL
ALARM INDICATION
DIGITAL DISPLAY
THUMB SCREW
PUSHBUTTON SWITCH
FOR ALARM RESET
TOGGLE SWITCH FOR
ALARM BYPASS
MODULE HANDLE

INSTALLATION AND START UP
PT920 Enclosure must be installed in a safe area. Figure 2 shows the
mounting holes for the stainless steel enclsoure
Main control rack assembly can hold up to sixteen (16) PT920 series
control modules. On the front panel of each module a captive screw is
provided to secure the module to the rack. Do not use excessive force to
tighten the screw. Also a handle is provided to facilitate for insertion and
removal of the module from the rack assembly.
Figure 2. PT920-16 Stainless Steel Enclosure - Dimensions
9

AC / DC Power Up
AC Power Input
If an AC/DC Power supply is installed in the unit then
Din-Terminals are installed on the lower left corner of
the Main connection board for the main AC line input.
The connections on the Din-terminal blocks are labeled
L N G. Connect the external AC power to this
terminal.
DC Power Input
If the unit is DC powered the simply connect 24 VDC
supply to the 2 pin green terminal labeled DC-Iinput
on the main connection board.
Refer to figure 3 for the location of AC and DC terminals
10

11
Figure 3. PT920-16 Monitor / Controller - Main Connection board with
16 each PT920 Series control modules installed
HOUSTON, TX
PEM−TECH, INC.
HOUSTON, TX
PEM−TECH, INC.
ALARMS
BYPASS
NORMAL
BYPASS
ALARMS
NORMAL
PPM H2S
RESET
HI−HI
MALF
RESET
MALF
HI−HI
LOW
HIGH
LOW
HIGH
PPM H2S
MODEL PT 920
H2S MONITOR
CHANNEL 1
MODEL PT 920
H2S MONITOR
CHANNEL 2
ALARMS
NORMAL
HO UST O N , TX
PEM−TECH, INC.
BYPASS
ALARMS
NORMAL
HOUSTON, TX
PEM−TECH , INC.
HOUSTON, TX
PEM−TECH, INC.
BYPASS BYPASS
ALARMS
NORMAL
BYPASS
ALARMS
NORMAL
HOUSTON, TX
PEM −TECH , INC.
ALARMS
HOUSTON, TX
PEM−TECH, INC.
BYPASS
NORMAL
HOUSTON, TX
PE M −T EC H , IN C.
BYPASS
ALARMS
NORMAL
CHANNEL 6
LOW
PPM H2S
HIGH
HI−HI
MALF
RESET
RESET
HI−HI
MALF
LOW
HIGH
PPM H2S
RESET
MALF
HI−HI
LOW
HIGH
PPM H2S
MODEL PT 920
H2S MONITOR
CHANNEL 4
MODEL PT 920
H2S MONITOR
CHANNEL 3
MODEL PT 920
H2S MONITOR
CHANNEL 5
LOW
HIGH
HI−HI
MALF
RESETRESET
HI−HI
MALF
LOW
HIGH
RESET
HI−HI
MALF
LOW
HIGH
MODEL PT 920
H2S MONITOR
CHANNEL 7
H2S MONITOR
MODEL PT 920 MODEL PT 920
H2S MONITOR
CHANNEL 8
LEL MONITOR
MODEL PT 920
HIGH
LOW
MALF
HI−HI
RESET
PEM−TECH , INC.
HOUSTON, TX
PEM−TECH, INC.
HOUSTON, TX
NORMAL
BYPASS
ALARMS
NORMAL
ALARMS
BYPASS
PEM−TECH, INC.
HOUSTON, TX
RESET
MALF
HI−HI
LOW
HIGH
RESET
HI−HI
MALF
LOW
HIGH
LEL MONITOR
MODEL PT 920
LEL MONITOR
MODEL PT 920
NORMAL
BYPASS
PEM−TECH, INC.
HOUSTON, TX
ALARMS
PEM−TECH, INC.
HO UST O N , TX
NORMAL
ALARMS
BYPASS BYPASS
NORMAL
ALARMS ALARMS
PEM−TECH, INC.
HOUSTON, TX
NORMAL
BYPASS
PEM −TECH , INC.
HOUSTON, TX
NORMAL
ALARMS
BYPASS
PE M −T EC H , IN C.
HOUSTON, TX
NORMAL
ALARMS
BYPASS
MODEL PT 920
LEL MONITOR
HIGH
LOW
MALF
HI−HI
RESET
RESET
MALF
HI−HI
LOW
HIGH
RESET
HI−HI
MALF
LOW
HIGH
% LEL % LEL
LEL MONITOR
MODEL PT 920
LEL MONITOR
MODEL PT 920
RESET
MALF
HI−HI
% LEL
LOW
HIGH
RESET
MALF
HI−HI
LOW
HIGH
% LEL
LEL MONITOR
MODEL PT 920
LEL MONITOR
MODEL PT 920
CHANNEL 16CHANNEL 15CHANNEL 14CHANNEL 13CHANNEL 12CHANNEL 11CHANNEL 10CHANNEL 9
PPM H2S PPM H2SPPM H2S
% LEL % LEL % LEL % LEL
+
−
E
TOXIC
(H2S)
LEL
−
E
+
E
−
−
E
+
+
E
−
−
E
+
+
E
−
−
E
+
+
E
−
−
E
+
+
E
−
−
E
+
+
E
−
−
E
+
+
E
−
−
E
+
+
HI−HI
NO
COM
FAULT
NC
−T
+T
RS485
SHLD
+V
GND
COM
AL1
AL2
AL3
AL4
+V
GND
RST/ACKDC−OUTRELAY−OUTRELAY PWR
DC−IN
+V
GND
JMP−1
JMP−9
JMP−2
JMP−10
JMP−3
JMP−11
JMP−4
JMP−12
JMP−5
JMP−13
JMP−6
JMP−14
JMP−7
JMP−15
JMP−8
JMP−16
CH−1
CH−9
CH−2
CH−10
CH−3
CH−11
CH−4
CH−12
CH−5
CH−13
CH−6
CH−14
CH−7
CH−15
CH−8
CH−16
GAS MONITOR
MODEL PT920−16
O
1
POWER
HOUSTON, TEXAS
RESET
ALARM
MASTER ALARM
RESET SWITCH
JUMPER SELECTION
FOR H2S/LEL CONTROL
MODULE TYPE
24VDC
POWER IN
SENSOR INPUTS
CH1 − CH16
NC
COM
NO
MASTER ALARM
RESET SWITCH
CONTACTS
CONNECTION TO
AUX RELAY BOARD ASSEMBLY
(RELAY PWR & OPEN DRAIN OUTPUTS)
AC POWER SWITCH
(IF AC POWER SUPPLY
INSTALLED)

Connecting Sensors to the Monitor
Connecting 4-20mA Transmitter (Gas Sensors)
(Toxic or LEL Combustible Control Modules)
Three (3) pin screw type terminals are provided on the main connection
board for remote sensor connection. The terminals are labeled as CH-1
thru CH-16 and each pin is identified as +, - , & E for sensor DC supply,
ground, and 4-20mA input 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 sensor connection 4-20mA transmitters.
Figure 4. Sensor connection 4-20mA Transmitter
−
+
mA
SIGNAL
SENSOR
3 CONDUCTOR
SHIELDED CABLE
4−20mA
SENSOR / TRANSMITTER
SENSOR INPUT TERMINAL ON
PT920 MAIN CONNECTION BOARD
−
E
CH−1 +
TYPICAL SENSOR
CONNECTION BOARD
12

Connecting Proximity Sensors (Contact switches)
(Status Input Modules)
For proximity sensors or contact switches only 2-wire connections are
needed. Simply connect + & E terminal pins to the proximity sensors.
CAUTION ! Do not connect “-“ terminal to the sensor as it may blow the fuse
on the control module
Figure 5. Proximity Sensor connection to PT920 Input Module type
13
−
E
+
CH−1
PROXIMITY SENSOR
CONTACTS CLOSED
NORMAL
CONTACTS OPEN
ALARM
SCHEMATIC
PROXIMITY SENSOR SENSOR INPUT TERMINAL ON
PT920 MAIN CONNECTION BOARD
CAUTION !
DO NOT USE "−" CONNECTION
2−WIRES: + & E

Figure 6. PT920 Connection Board. Typical 4-20mA sensor connection
PT920−16 MAIN CONNECTION BOARD
(NOT SHOWN COMPLETE FOR CLARITY)
ON AUXILIARY ALARM RELAY BOARD ASSEMBLY
JUMPER SELECTION FOR PROPER ALARM ACTIVATION
JMP−9
DC−IN
+V
−
−
GND
CH−9
+
−
E
E
+
−
E
E
(H2S)
LEL
CH−1
++
TOXIC
JMP−1
−
−
−
−
−
−
CH−11
CH−10
+ E
−
E
CH−13
CH−12
+
−
E
E
+
−
E
E
CH−15
CH−14
+
−
E
E
+
−
E
E
CH−16
+
−
E
E
AS SHOWN: JMP1 THRU JMP8 SELECTED AS TOXIC (H2S) CHANNEL TYPE
JMP9 THRU JMP16 SELECTED AS LEL CHANNEL TYPE
JMP−5
JMP−10
+
CH−2CH−3
JMP−2JMP−3
CH−4
+
JMP−11
CH−5
+
JMP−12
JMP−4
CH−6
+
JMP−13
+
CH−7
JMP−14
JMP−6
CH−8
+
JMP−15JMP−16
JMP−7JMP−8
SHIELDED CABLE
SENSOR
SIGNAL
3 CONDUCTOR
+
−
mA
TYPICAL SENSOR
CONNECTION BOARD
4−20mA
SENSOR & TRANSMITTER
14

Auxiliary 10-Amp Alarm Relay Board
The auxiliary relays interface board is located in lower right corner of the
main termination board. See figure 7 for wiring details of the relay board
to the main PT920 connection board. There are 4 relay contacts on the
relay board assembly (Alarm 1 thru Alarm 4). Typically these 4 relays are
configured as Low & High for Toxic and Low & High for LEL type control
modules. Therefore, Alarm-1 and Alarm-2 are configured as Low and
High alarm contacts for Toxic and Alarm-3 and Alarm-4 as Low and High
for LEL alarms. In order for alarm relays to function properly as
mentioned above jumpers are provided (JMP-1 thru JMP-16) right above
the terminal blocks for sensor input.
Each set of JMP-1 thru JMP-16 is designated for channel or control module
1 thru 16. If the channel or control module type is Toxic then set jumpers
to TOXIC position. Similarly for LEL set jumpers to LEL position. See
figure 8.
Figure 7. Auxiliary alarm relay board interface to PT920 Main
connection board
15
JMP−16JMP−15
CH−15
CH−7
+
E
CH−16
−
NC
NO
COM
COM
NO
+
−
E
CH−8
−T
+T
NC
SHLD
JMP−8
DC−OUT
+V
RELAY−OUT
AL3
HI−HI
GND
AL4
+V
FAULT
RELAY PWR
AL2
AL1
COM
GND
RS485
RST/ACK
+
E
−
−
+
E
10A
RELAY
10A
RELAY
10A
RELAY
10A
RELAY
GND
+V
AL4
AL3
AL2
AL1
COM
NC
C
NO
ALARM−4
ALARM−3
NC
NO
C
ALARM−2
NC
NO
C
ALARM−1
NC
NO
C
24VDC
10AMPS AUXILIARY
RELAY BOARD ASSEMBLY
PT920−16 MAIN CONNECTION BOARD
(COMPLETE BOARD NOT SHOWN FOR CLARITY)

Figure 8. Jumpers to configure control modules as TOXIC and LEL for
proper alarm relay activation on the Aux Relay Board Assembly.
16
+
−
E
TOXIC
(H2S)
LEL
−
E +
E
−
−
E +
+
E
−
−
E +
+
E
−
−
E +
+
E
−
−
E +
+
E
−
−
E +
+
E
−
−
E +
+
E
−
−
E +
+
HI−HI
NO
COM
FAULT
NC
−T
+T
RS485
SHLD
+V
GND
COM
AL1
AL2
AL3
AL4
+V
GND
RST/ACK DC−OUT RELAY−OUT RELAY PWR
DC−IN
+V
GND
JMP−1
JMP−9
JMP−2
JMP−10
JMP−3
JMP−11
JMP−4
JMP−12
JMP−5
JMP−13
JMP−6
JMP−14
JMP−7
JMP−15
JMP−8
JMP−16
CH−1
CH−9
CH−2
CH−10
CH−3
CH−11
CH−4
CH−12
CH−5
CH−13
CH−6
CH−14
CH−7
CH−15
CH−8
CH−16
NC
COM
NO
JUMPER SELECTION FOR PROPER ALARM ACTIVATION
ON AUXILIARY ALARM RELAY BOARD ASSEMBLY
AS SHOWN: JMP1 THRU JMP8 SELECTED AS TOXIC (H2S) CHANNEL TYPE
JMP9 THRU JMP16 SELECTED AS LEL CHANNEL TYPE
PT920−16 MAIN CONNECTION BOARD
(NOT SHOWN COMPLETE FOR CLARITY)

Wiring Audio / Visual Alarms
Figure 9 shows a typical wiring diagram for connecting alarm devices to
an Auxiliary Relay board assembly. Each relay on the auxiliary board is
activated by the control module. Note that contacts are dry or potential
free. Figure 9 shows a sample wiring diagram for 2 separate alarm
stations, Toxic and Combustible gas Alarm. Also refer to the wiring
details provided by the manufacturer of the alarm devices.
Note that Hi-Hi and FAULT alarm contacts are common to all 16 control
modules and are rated 5 AMPS each
Figure 9. Wiring diagram for audio and visual alarm stations to Auxiliary
relay board assembly.
NC
ALARM−4
ALARM−1
10A
GND
+V
24VDC
AL1
COM
AL2
AL4
AL3
RELAY
ALARM−2ALARM−3
C
NO
RELAY BOARD ASSEMBLY
10AMPS AUXILIARY
AUDIO / VISUAL
AUDIO / VISUAL
CONNECTION TO
PT920 MAIN CONNECTION BOARD
POWER SOURCE
FOR ALARMS
SUPPLY
RETURN
LEL ALARMS
TOXIC/H2S ALARMS
NC
C
NO
NC
C
NO
NC
C
NO
10A
RELAY
10A
RELAY
10A
RELAY
In−Line Fuse
17

Start Up
Follow the instructions below for 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
Before connecting the AC power to the AC terminal on the termination
block make sure that POWER Switch on the unit is in OFF or ‘0’ position.
Flip the Power switch to ON or ‘1’ position to turn on the power to the
monitor and verify following conditions.
1. All 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. These channel number will flash for few seconds. The
channel number is also referenced as a unique Module address for
proper serial communication with annunciators and data transmitters.
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.
18

Setting Control Module Address / ID
***** Skip this section if RS485 or Remote annunciator are not used ******
Each PT920 control module must have a unique address for RS485
communication with the remote annunciator. Control modules must be
addressed 1 thru 16. The current module address is flashed for few
seconds during upon startup. If the modules do not display the right
address then change the address and discussed in the next section
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.
19

NORMAL OPERATION AND ALARMS
Each Control module on the main control panel has push button switch
for Alarm Reset or Adjust and an Alarm Bypass toggle switch. Also 2 digit
bright display and LED indicators for visual alarms.
Gas Control Modules – For Gas Sensors / 4-20mA Transmitters
During normal operation the toggle switch on the module front panel
must in NORMAL position. The display should be reading the gas
concentration proportional to 4-20mA signal transmitted by the gas
sensor. If the gas concentration exceeds the programmed alarm level the
relays and the visual alarm LED indicators will be activated. To bypass
the alarms simply put the toggle switch in BYPASS position. Alarm relays
will be deactivated and display and visual LED indicators will be flashing
to indicate the alarm bypass mode.
Input Control Modules – For Proximity Sensors / Contact Switces
Input control modules monitors the signal return through the proximity
sensors. The module will display CL if there is no break in the signal and
switch is CLosed. On the module front panel there are 2 red LED
indicators for visual alarms. The “STATUS” LED indicator is activated
as soon as the module detects the break in the signal. However, the Alarm
is activated only if the signal break elapsed time is more than 15 seconds.
Also the display will indicate “OP” as in contact OPen. Only Low Alarm
or Alarm 1 is energized. If the signal return is restored within 15 seconds
then no alarm is activated.
The “STATUS” LED is helpful in troubleshooting when the contacts on
the proximity switch are loose and signal is intermittently broken and
restored.
To bypass the alarms simply put the toggle switch in BYPASS position.
Alarm relays will be deactivated and display and visual LED indicators
will be flashing to indicate the alarm bypass mode.
20