Orbit Merret OM 351 Instruction Manual
GUARANTEE
YERS
OM 351
3 1/2 DIGIT PROGRAMMABLE
DC VOLTMETER/AMMETER
AC VOLTMETER/AMMETER
PROCESS MONITOR
THERMOMETER FOR PT 100/500/1 000
THERMOMETER FOR NI 1 000
THERMOMETER FOR THERMOCOUPLES
DISPLAY INST. FOR LIN. POTENTIOMETERS
OHMMETER
1
INSTRUCIONS FOR USE OM 351
SAFETY INSTRUCTIONS
Please, read the enclosed safety instructions carefully and observe them!
These instruments should be safeguarded by isolated or common fuses (breakers)!
For safety information the EN 61 010-1 + A2 standard must be observed.
This instrument is not explosion-safe!
TECHNICAL DATA
Measuring instruments of the OM 351 series conform to the European regulation 89/336/EWG and the Ordinance
168/1997 Coll.
They are up to the following European and Czech standards:
CNS EN 55 022, class B
CNS EN 61000-4-2, -4, -5, -6, -8, -9, -10, -11
The instruments are applicable for unlimited use in agricultural and industrial areas.
CONNECTION
Supply of energy from the main line has to be isolated from the measuring leads.
ORBIT MERRET, spol. s r.o.
Vodnanska 675/30
198 00 Prague 9
Czech Republic
Tel: +420 - 281 040 20 0
Fax: +420 - 281 040 299
e-mail: orbit@merret.cz
www.orbit.merret.cz
2
1. CONTENTS
1. CONTENTS
1. Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Instrument description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Programming modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Control keys functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Setting the DP and the (-) sign. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1 Guide through minimum instrument setting, calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2 User menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2.1 Internal values resetting (Tare) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2.2 Setting the limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.2.3 Setting the display brightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3 Configuration menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.3.1 Configuration mode - INPUT
4.3.1.1 Internal values resetting (TARE). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.3.1.2 Setting the measuring range, displacement, compensation and measuring rate. . . . . . . . . . . . . . . 16
4.3.1.3 Setting the external control input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4.3.1.4 Setting functions of the control key (ENTER) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.3.2 Configuration mode - CHANNELS
4.3.2.1 Projection on the display (MIN, MAX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.3.2.2 Setting the digital filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.3.2.3 Setting the decimal point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.3.3 Configuration mode - OUTPUT
4.3.3.1 Cofiguration and setting the limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.3.3.2 Setting the data output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.3.3.3 Setting the analog output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.3.3.4 Setting the display brightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4.3.4 Configuration mode - SERVICE
4.3.4.1 Setting the menu access - resetting and limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.3.4.2 Restoration of the manufacture setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.3.4.3 Calibration of the input range (DU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.3.4.4 Setting new access password . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.3.4.5 Instrument identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
5. Method of measuring of the cold junction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6. Data protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7. Error statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8. Technical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
9. Instrument dimensions and installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
10. Certificate of guarantee . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3
INSTRUCIONS FOR USE OM 351
2. INSTRUMENT DESCRIPTION
DESCRIPTION
The OM 351 model series are 3 1/2 digit programmable panel instruments, manufactured in the following
alternatives:
OM 351DC DC voltmeter/ammeter
OM 351AC AC voltmeter/ammeter
OM 351PM Process monitor
OM 351RTD Thermometer for Pt 100/500/1 000, Ni 1 000
OM 351T/C Thermometer for thermocouples
OM 351DU Display instrument for linear potentiometers
OM 351OHM Ohmmeter
The instruments are based on an 8-bit microcontroller with A/D converter, that secures high accuracy, stability and
easy operation of the instrument.
Programmable projection of the display
Calibration projection for the beginning and the end of the output range
setting the output type
Projection ±1999
Digital filters
Radius of insensitiveness adjustable in process units
Exponential average from 2…100 measurements
Mathematic functions
Tare* assigned to reset the display in case of non-zero input signal
External control
Hold display/instrument blocking
Lock locking the control keys or the access into Configuration menu
Tare tare activation
4
* only for types DC, PM, DU
2. INSTRUMENT DESCRIPTION
OPERATION
The instrument is set and controlled by five control keys located on the front panel. All programmable settings of the
instrument are realized in two adjusting modes:
Configuration menu (hereinafter referred to as „CM“) is protected by an optional number code and contains
complete instrument setting
User menu may contain arbitrary programming settings, defined in „CM“ with another selective restric
tion (see, change)
All programmable parameters are stored in the EEPROM memory (they hold even after the instrument is switched
off).
EXTENSION
Excitation is suitable for feeding sensors and converters. It has a galvanic isolation of 15 VDC.
Comparators are assigned to control two limit values with relay output. The limits have adjustbale hysteresis as
well as selectable delay of the switch-on. Reaching the preset limits is signalled by LED and simultaneously by the
switch-on of the relevant relay.
Data outputs are for their rate and accuracy suitable for transmission of the measured data for further projection or
directly into the control systems. We offer an isolated RS 232 and RS 485 with the ASCII protocol.
Analogue outputs will find their place in applications where further evaluating or processing of measured data
in external devices is required. We offer universal analog output with the option of selection of the type of output
- voltage/current. The value of analog output corresponds with the displayed data and its type and range are
selectable in the programming mode.
* only for type T/C
5
INSTRUCIONS FOR USE OM 351
232
485
3. CONNECTION
The lead for feeding the instrument should not be in the proximity of the incoming low-potential signals.
Contactors, motors with larger input power and other efficient elements should not be in the proximity of the instru-
ment.
The lead into the input of the instrument (the measured quantity) should be in sufficient distance from all power leads
and appliances. Provided this cannot be secured it is necessary to use shielded leads with connection to ground.
The instruments are tested in compliance with standards for use in industrial area, yet we recommend to abide by
the above mentioned principles.
L2
L1
12 3
-
+
L
N
POWER SUPPLY
Grounding on terminal „E“ has to be connected at
all times
In RTD input with 2- or 3-wire connection it is necessary
to link the unconnected inputs (13+14/15+16 or 13+14)
on the terminal block
Relay parameters listed in Technical data apply for
resistance load. Upon connection of induction load we
recommend fi tting the leads to relay 1 A with a fuse for
protection of maximum load.
6
4567
E
8910
RxD
GND
TxD
232
GND
Rx/Tx-
Rx/Tx+
485
-
+
GND
Analog output
14 15 1611 12 13
-
+
GND
Hold/Lock
INPUT
E-
Hold/Lock
S-
S-
CJC
S+
E+
ES+E-
ES+ES-
OM 351T/C
OM 351RTD, OHM
3. INSTRUMENT CONNECTION
232
485
L2
L1
MEASURING RANGES
12 3
-
+
L
N
POWER SUPPLY
4567
8910
E
GND
GND
GND
TxD
232
Rx/Tx-
485
RxD
Rx/Tx+
-
+
Analog output
-
+
Excitation
14 15 1611 12 13
-
+
+
GND
Hold/Lock/Tare
Hold/Lock
Hold/Lock/Tare
INPUT 1
GND
INPUT 1
z k
INPUT 2
Type Input 1 Input 2 Input 3
OM 351 AC
OM 351 AC
OM 351 DC
OM 351 DC
OM 351 PM
OM 351 OHM
Input 1 > 0…60 mV * 0…150 mV * 0…300 mV * 0…1 A * 0…5 A
Input 2 > 0…10 V * 0…100 V * 0…150 V * 0…250 V * 0…450 V
±2/±20 mA ±0,2/±2 V ±20/±200 V
0…1/5 A 0…60/150 mV
0/4…20 mA 0…2 V 0…5/10 V
0…200 Ohm * 0...2 kOhm * 0...100 kOhm * 5…105 Ohm
+
INPUT 3
INPUT 3
OM 351DC, PM
OM 351AC
OM 351DU
7
INSTRUCIONS FOR USE OM 351
4. INSTRUMENT SETTING
Setting and controlling the instrument is performed through 5 control keys on the front panel. By means of these controls
it is possible to browse through the operating program and to select and set the required values.
Measured value
Relay status
ON the digit is lit
OFF the digit is not lit
OFF the digit is flashing
limits with restriction
(delay)
CONFIGURATION MODE USER MODE
143.7
1T2 M
• designated for professional service and maintenance • designated for instrument service
• complete instrument setting • may contain setting the limits, resetting
• access is password protected the tare and brightness, with restriction as
• authorization for "User mode" per the setting in "Configuration mode"
SYMBOLS USED IN THE INSTRUCTIONS
DC AC PM DU OHM RTD T/C
Indicates the setting for given type of instrument
Function
T Tare
CONTROL KEYS FUNCTIONS
MENU ENTER LEFT DOWN UP
Measuring mode
menu access tare* tare projection*
Moving around in the menu
exit the menu without
saving
Setting/selecting - items
cancel setting without
saving
Setting - numbers
cancel setting without
saving
8
move to next level back to previous level move to next item move to next item
confi rm selected item move down move up
confi rm selected
number
move to higher
decade
change of current
fi gure - down -
change of current
fi gure - up -
* if the function is permitted in CM
4. INSTRUMENT SETTING
SETTING THE DECIMAL POINT AND THE MINUS SIGN
DECIMAL POINT
Its selection in calibration modes, upon modification of the number to be adjusted is performed by the
control key
Positioning is performed by
Setting the decimal point may be performed correctly with the (+/-) signs being turned off.
MINUS SIGN
Setting of the minus sign is performed by the control key on higher decade. When editing the item the subtraction
must be made from the current number (e.g.: 13 >
ACCESS INTO THE CONFIGURATION MODE
with transition behind the highest decade, when the decimal point starts flashing.
/
.
, on class 100 > -87)
.
+
PAS
w/o saving
shift left
0,1,2…
000
9,8,7…
OK
INP.
CHA .
OUT.
SER.
The code from manufacture is always
preset to 000
In case of loss of access password it is possible to
use the universal access code "177"
If the code is preset to 000 than the
access into „CM“ is free, i.e. without call
for its setting
9
INSTRUCIONS FOR USE OM 351
4.1 GUIDE THROUGH MINIMUM INSTRUMENT SETTING
Access into the „Configuration menu“
+
PAS
Selection of the measuring range/input type
INP.
CHA .
OUT.
SER.
CL. T.
CFG
AUX.
KEY
w/o saving
shift left
MOD
M/S
0,1,2…
000
9,8,7…
DC - 1
0. 2 V
2. V
20. V
199. V
2. i
20. i
RTD
2-w
3-w
4-w
T/C
OK
DC - 2
60. m
150. m
1. a
5. a
PM
u 2.
u 5.
u10.
i 0.
i 4.
B
R
S
T
E
J
K
N
password
DC Input
- setting the input range is dependant on the
ordered measuring range
PM Input
- setting the input range
RTD Input
- setting the type of connection
- in case of 2- or 3-wire connection it is
necessary to link the unconnected inputs (see
the connection)
T/C Input
- setting the type of thermocouple is dependant
on the ordered measuring range
- B type B Range 1
R type R Range 2
S type S
T type T
E type E Range 3
J type J
K type K
N type N
Entering the introductory
PAS
access password
Standard manufacture
000
setting of the access
Setting the instrument
MOD
measuring range
10
Setting projection on the display
INP.
CHA.
OUT.
SER.
If the code is preset to 000 than the
access into „CM“ is free, i.e. without call
for its setting
MI N
MAX
FI L .
FOR.
4. GUIDE THROUGH MINIMUM INSTRUMENT SETTING
Setting the display
MI N .
projection for minimum value
of the input signal
- range of the setting is ±1999
value of the input signal
- range of the setting is ±1999
Input type Displayed items of the menu
DC MIN, MAX
PM MIN, MAX
DU MIN, MAX
OHM MIN, MAX, *LEA.
RTD *LEA., r. Ad.
T/C CJC., t. CJ.
* only for 2-wire
Setting the display
MAX
projection for maximum
11
INSTRUCIONS FOR USE OM 351
4.2 USER MENU
• designated for instrument service
• may contain setting the limits, analog and data output and brightness, with restriction as per the setting in "Configuration mode"
23.6
INP.
Tare resetting
INP. CL. t..
Tare resetting
OUT. LIM.
Setting limits,
hysteresis and
delay
bri.
Setting the
display brightness
4.2.1 RESETTING THE INTERNAL VALUES
CL. t.INP.
OUT.
Adjustable authorization of access into items,
see page 26
Setting limits and display brightness
Projection of items and their accessability
depends on the setting of access rights in the
„Confi guration menu“
Tare resetting
CL. t .
OUT.
12
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