Operating Manual

LDM250/LDM450/LDM650
Low Voltage

Multipoint unit
English ·INFICON

LDM 250 450 650 Low voltage Multipoint unit ............................................................................................. 3

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voltage Multipoint unit

LDM 250 450 650 Low

voltage Multipoint unit

English ................................................................................................................................................................... 9INFICON

Fig. 1

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LDM 250 450 650 Low

LDM 250 450 650 Low

voltage Multipoint unit

voltage Multipoint unit

LDM 250 450 650 Low voltage Multipoint unitINFICON

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voltage Multipoint unit

LDM 250 450 650 Low

voltage Multipoint unit

Wiring diagram

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Fault U<0,1V

Fault U<0,1V

T<Xmin.

T>Xmin.

T<Xmin.

T>Xmin.

T<Xmin.

T>Xmin.

T=<4 (h)T=>4 (h)

X

X

X

X

X

X

X

X

LDM 250 450 650 Low

voltage Multipoint unit

LEDs (per channel)
Power/active
Alarm C (low level) (Vdc)
Alarm B (middle level) (Vdc)
Alarm A (high level) (Vdc)

Flash000

X000Flash
Flash
Flash
Flash

X
Flash
00X
X
00X
X
Flash
0X
X
X
0X
X
X
Flash

X
X
X
X

0Flash
Flash
Flash

00X
0E
E
E
E
E

E
E
E
E
E

E
E
E
E
E

E
E
E
E
E

NE
E
E
E
E

NE
E
E
E
E

NE
NE
E
E
E

NE
NE
E
E
E

NE
NE
NE
E
E

E
E
E
NE
E

E
E
E
NE
NE

000
0

Summary Relay output (Energised/Not energised)
Alarm CNE
Alarm B
NE
Alarm ANE
Fault (Relay D) (no time delay)
NE
Fault (Relay D) (4 hour time delay)
NE

Alarm B
U=(>B,<A)

Alarm A U>AService modeX

Alarm C
U=(>C,<B)

NormalX

Auto reset Man reset

Test mode sequense

5s

10 s

15 s

20 s

25 s

30 s

35 s

40 s

45 s

50 s

55 s

60 s

LED Power/active
LED Alarm C (low level)
LED Alarm B (middle level)
LED Alarm A (high level)

0000

Flash
000

X
000

Flash
Flash
Flash
Flash

X
Flash
00

X
X
00

X
X
Flash
0

X
X
X
0

X
X
X
Flash

X
X
X
X

0
Flash
Flash
Flash

00
X
0HFC, HFO, HCFC

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H3 = 20 cm

X = 50 cm

Y = 20 cm(WD) 724-250 450 650 -Low Voltage Operating Manual 220627.docxLDM 250 450 650 Low

0X
no indication

Power off
T<Xmin, X = delay in minutes. Letter U =signal from sensor (Vdc).
LEDs (terminal board)
PowerBuzzer (disabled via jumper)

voltage Multipoint unit

PreheatLogical matrix

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voltage Multipoint unit

LDM 250 450 650 Low

voltage Multipoint unit

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LDM 250 450 650 Low

LDM 250 450 650 Low

voltage Multipoint unit

voltage Multipoint unit

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voltage Multipoint unit

LDM 250 450 650 Low

voltage Multipoint unit

INFICONINFICON

EnglishLDM 250/450/650 Low voltage Operating Manual
1. Table of Contents
2.

Features ................................................................................................................................................. 10

3.

Models ................................................................................................................................................... 11

4.

Function ................................................................................................................................................. 11

4.1 AUTO/MANUAL ALARM RESET ......................................................................................................... 11
4.2 ALARM TIME DELAY (T1) .................................................................................................................... 11
4.3

RESET/TEST/SERVICE-BUTTON (7) ......................................................................................... 11

4.3.1

SERVICE MODE ............................................................................................................................... 12

4.3.2

FAULT MODE ................................................................................................................................... 12

4.4 INTERNAL BUZZER AND 24VDC AUXILIARY OUTPUT ................................................................. 12

5Location/Installation ........................................................................................................................... 13

5.1

ALARM LEVELS / CHANGING ALARM LEVELS ....................................................................... 13

5.2

Function Control .............................................................................................................................. 13

6

Technical Data ...................................................................................................................................... 13

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EnglishEnglish4.5 Remote sensors ...................................................................................................................................... 13

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2. Features
The LDM250, LDM450 and LDM650 are central units with two/four/six channels(sensors).
The LDM250/450/650 is a multi-channel microprocessor-based gas monitoring system. Each, upto a maximum of six channels, can be individually configured to monitor different gases with up tothree alarm concentrations all with status LEDs.
Other features include:- User configurable alarm time delays- Manual/auto alarm reset for each channel- Built-in service function and self-test program- Four alarm relays with 230 volts rated SPDT contacts- Failsafe relay operation on power loss
- Audible alarm- Low voltage output for auxiliary alarm indication.

Please Note!
The LDM250, LDM450 and LDM650 are normally supplied with default set alarm
thresholds. These must be verified or reset during commissioning. Alarm levels
must always be set on each channel for proper gas and detector type.
Alarm level

OffsetAlarm C

1,0V

Alarm B

2,0V

Alarm A

3,0V

EnglishEnglishDefault settings from factory:

Alarm levels, factory settings are:
HFC, HFO, HCFC (ppm)

C=100

B=1000A=2000

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3. Models (sensors included)
Model

Used for724-250-G1

two channels(sensors)

724-450-G1

four channels(sensors)

724-650-G1

six channels(sensors)4. Function
After connecting each detector and applying power, the green LED on each channel will flash as
the pre-heat process commences. After approximately 4 minutes the green LED will illuminate
permanently, and the sensor is fully operational. Each channel has one yellow and two red
warning LEDs. The yellow LED indicates a low-level gas leak (above alarm threshold C) whilst thetwo red LEDs indicate gas concentrations above thresholds B and A.
When gas is detected above the respective alarm threshold the appropriate LEDs will flash until
the appropriate time delay has expired when it is permanently illuminated, and the corresponding
relay contacts change state. As the gas concentration subsides the LEDs and relays will return totheir normal state unless the ‘manual reset’ function has been selected. The audible alarm will
initiate if it is configured with the respective alarm threshold and cannot be muted. Technicians

4.1 AUTO/MANUAL ALARM RESETDIP switch (5) no3 on each channel’s control card manages the alarm reset function. “ON”
enables Auto reset and “OFF” enables Manual reset, via pressing “Reset/Test/Service”-button(7).

4.2 ALARM TIME DELAY (T1)
DIP-switch (5) controls the alarm time delay for each channel.
no1no2onon

No alarm delay

off

on

1 minute delay

onoff

10 minutes delay

offoff30 minutes delay

4.3 RESET/TEST/SERVICE-BUTTON (7)Reset/Test/Service-functions is accessible via a pushbutton on the cover.
Pressing the “Reset/Test/Service”-button (7) on any channel for 5 seconds initiates the test
program. This sequentially energizes each LED and relay at five second intervals. All LEDs on thechosen channel will go out when the test program has started.

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EnglishEnglishcan inhibit the alarm by selecting ‘Service Mode’.

INFICON

4.3.1

SERVICE MODE

Pressing the” Reset/Test/Service” button (7) for 10 seconds will inhibit all alarm functions for thechosen channel for 60 minutes. Service mode is indicated by all LEDs on the chosen channel isflashing. A new 60 minute inhibit period can be initiated by repeating the process. Normal
operation will be automatically resumed after 60 minutes or can be cancelled by pressing the“Reset/Test/ Service”-button briefly.

4.3.2

FAULT MODE

In the event of a detector failure (GV offset < 0,1V) or disconnection of the interconnecting wiring
a fault condition will be indicated by loss of the green 'Active' LED, the other LEDs start to flash
and the alarm relay D is de-energised. In the event of power failure all relays (A, B, C & D) will bede-energized. Connections are available for an optional battery back-up to enable total continuityof operation in the event of a power failure. A 4-hour delay can be configured for relay D toprevent nuisance alarms. This is activated by setting DIP switch (5) no4 on the respective channelcard to 'ON'. The operation of the LEDs will remain unchanged.

4.4 INTERNAL BUZZER AND 24VDC AUXILIARY OUTPUT
board and can be user configured to operate from alarm concentration A(no1), B(no2) or C(no3).
Setting the DIP-switch to ON for the respective alarm level selects the appropriate alarm level.
The 24VDC auxiliary alarm output is always activated together with the buzzer. However, byremoving jumper Bb (3) the buzzer can be disabled.

Please Note!
After being powered off for prolonged periods the sensor may take several
minutes to stabilize during which time ‘false’ alarms may be initiated. Such ‘false’
alarm shall disappear within a few minutes.

LED A
LED B

n1n2
ON

n 3 ALARM RESET: ON=AUTO, OFF=MANUELL
n 4 FAULT DELAY: ON=4h DELAY, OFF= NO DELAY

LED C
POWER

TEST TERMINALABCRESET/TEST

ALARM A
ALARM B
ALARM C(-)
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EnglishEnglish

The internal buzzer (1) and 24VDC output can be activated by the DIP-switch (4) on the terminal

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4.5 Remote sensors
LDMR series is a range of remote sensors designed for use with the LDM units.
Low voltage LDM250, LDM450, or LDM650 units include either 2, 4, or 6 LDMR remote sensors
for detecting HFCs, HCFCs, and mixtures and carbon dioxide (CO2).

Please Note!
The sensors used in the LDMR series have limited selectivity and are therefore
not gas specific. Care should be taken when installing the equipment to minimize
any cross contamination from other gases or vapours.
For further guidance on specific applications contact us.

5Location/Installation

Correct location of the LDMR is essential to ensure optimum operation of the system. Special
consideration must be given to air movement and whether the gas to be detected is heavier orlighter than air. For gases heavier than air (e.g. Refrigerants (HFC, HCFC) or CO2) the sensor
should ideally be located approximately 20cm above floor level. Connect the sensor according to
the wiring diagram.
NOTE! For unused channels a jumper (8) must be mounted and a >100 kohms resistor (attached)
Otherwise, the channel will indicate a fault alarm.
When changing or replacing a LDMR a new calibration must be performed.

5.1 ALARM LEVELS / CHANGING ALARM LEVELSThe unit is normally supplied with default set alarm thresholds.
These must be verified or reset during commissioning.
To set or change the alarm thresholds you need a MCT150 Calibration tool and a small
screwdriver.
Full details regarding custom alarm set-points for a range of gases together with a detailed
procedure are outlined in specific data sheets. Multiple gases and alarm set-points can beaccommodated on a single LDM as each channel is totally independent.

5.2 Function Control
Testing the system is recommended to be done once a year. A basic function test can be
performed using MCT150. Extended control and calibration require test gas with a specificconcentration.

6Technical Data

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EnglishEnglishmust be installed between (+) and (S) to prevent open sensor alarms.

INFICON

Standard Housing:

ABS/PC plastic, (IP67)

Power supply:

24 AC/ 24V DC, max 10VA

Status Indication:

Common Power LED
Individual LED channel indication ofsensor active and 3 alarm levels.

Inputs:2, 4 or 6 channels 0-5VDC

Alarm levels:

3 levels/channel, individually set within 0,5...4,8V

Hysteresis:

alarm levels +- ~100mV

Output relays (4 off):

Volt free contacts, SPDT rated 230V AC / 5amps.

Output (voltage):

24VDC max 150mA

Ambient temp:+-0 Deg C - + 50 Deg CSensor cable:

3 x 0,75mm2 max 50m(Screened)3 x 1,5mm2 max 150m

Dimensions:

180 x 255 x 60mm

Glands:12 x M16English

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