Kobold MPT Operating Manual
KOBOLD Model MPT
DRAFT
Universal Panel Display
Operating Instructions
KOBOLD Instruments, Inc.
1801 Parkway
Pittsburgh, PA 15205
P +1.412.788.2830
www.koboldusa.com
View Drive
KOBOLD Model MPT Operating Instructions
DRAFT
Disclaimer
The information contained in this document is subject to change
without notice. KOBOLD Instruments Inc. makes no representations
or warranties with respect to the contents hereof, and specifically
disclaims any implied warranties of merchantability or fitness for a
particular purpose.
Registered Trademarks
Modbus® is a registered trademark of Schneider Automation Inc. All
other trademarks mentioned in this document are the property of
their respective owners.
© 2016 KOBOLD Instruments Inc. All rights reserved.
INTRODUCTION
The KOBOLD Model MPT is a multipurpose, easy-to-use digital panel
meter. It accepts current, voltage, thermocouple, and RTD signals. The
four front panel buttons make the setup and programming an easy task.
The isolated 24 VDC transmitter power (optional) can be used to power
the input transmitter, the 4-20 mA output, or other devices.
The two relays (optional) can be used for alarm indication or process control
applications, such as pump alternation control.
Two relays and a 4-20 mA output are available together in the same meter.
The 4-20 mA isolated output and Modbus
options make the MPT an excellent addition to any system.
®
RTU serial communication
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KOBOLD Model MPT Operating Instructions
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ORDERING INFORMATION
Standard Models
85-265 VAC
Model
MPT-11500 MPT-11300 No options
MPT-11510 24 V transmitter supply
MPT-11502 MPT-11302 2 relays
MPT-11512 2 relays & 24 V transmitter supply
MPT-11503 MPT-11303 4-20 mA output
MPT-11513 4-20 mA output & 24 V supply
MPT-11523 4-20 mA output & dual 24 V supplies
MPT-11514 2 relays, 4-20 mA output, & 24 V supply
Large Display Models
85-265 VAC
Model
MPT-12500 MPT-12300 No options
MPT-12510 24 V transmitter supply
MPT-12502 MPT-12302 2 relays
MPT-12512 2 relays & 24 V transmitter supply
MPT-12503 MPT-12303 4-20 mA output
MPT-12513 4-20 mA output & 24 V supply
MPT-12523 4-20 mA output & dual 24 V supplies
MPT-12514 2 relays, 4-20 mA output, & 24 V supply
Accessories
Model Description
PDA7232 RS-232 serial adapter with PDA7420 included
PDA7420 MPT meter copy cable, 7' (2.1 m)
PDA7422 RS-485 serial adapter with PDA7420 included
PDA7485-I RS-232 to RS-485 isolated converter
PDA7485-N RS-232 to RS-485 non-isolated converter
PDA8485-I USB to RS-422/485 isolated converter
PDA8485-N USB to RS-422/485 non-isolated converter
PDA8006 USB Serial Adapter
MeterView® Free MeterView® software download at www.koboldusa.com
12-36 VDC
Model
MPT-11304 2 relays & 4-20 mA output
12-36 VDC
Model
MPT-12304 2 relays & 4-20 mA output
Options Installed
Options Installed
3
KOBOLD Model MPT Operating Instructions
DRAFT
Table of Contents
INTR
ODUCTION ------------------------------------------------------------ 2
ORDERING INFORMATION --------------------------------------------- 3
SPECIFICATIONS ---------------------------------------------------------- 7
General ------------------------------------------------------------------------------- 7
Process Input ---------------------------------------------------------------------- 8
Temperature Inputs -------------------------------------------------------------- 9
Relays Option -------------------------------------------------------------------- 10
Isolated 4-20 mA Transmitter Output ------------------------------------ 11
Serial Communications ------------------------------------------------------- 11
COMPLIANCE INFORMATION ---------------------------------------- 12
Safety ------------------------------------------------------------------------------- 12
Electromagnetic Compatibility --------------------------------------------- 12
SAFETY INFORMATION ------------------------------------------------ 13
INSTALLATION ------------------------------------------------------------ 14
Unpacking ------------------------------------------------------------------------- 14
Panel Mounting ------------------------------------------------------------------ 14
Connections ---------------------------------------------------------------------- 15
Connector Labeling ---------------------------------------------------------- 15
Power Connections ---------------------------------------------------------- 16
Signal Connections ---------------------------------------------------------- 16
Serial Communication ------------------------------------------------------- 20
Relays and 24 V Output Connections ----------------------------------- 20
Switching Inductive Loads -------------------------------------------------- 20
4-20 mA Output & Input Signal Connections -------------------------- 22
SETUP AND PROGRAMMING ---------------------------------------- 23
Front Panel Buttons and Status LED Indicators --------------------- 24
Display Functions and Messages ----------------------------------------- 25
Main Menu ------------------------------------------------------------------------ 28
Setting Numeric Values ------------------------------------------------------ 28
Setting Up the Meter (setu) ------------------------------------------------- 29
Setting the Input Signal (inpt) -------------------------------------------- 30
Setting the Decimal Point (dc.pt) ----------------------------------------- 31
Setting the Temperature Scale (F C) ---------------------------------- 31
Programming the Meter (prog) ------------------------------------------- 32
Scaling the Meter (scal) ---------------------------------------------------- 33
Calibrating the Meter (Cal) ------------------------------------------------- 35
Recalibrating Temperature Inputs (Cal) -------------------------------- 35
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KOBOLD Model MPT Operating Instructions
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Recalibrating Process Inputs (ICal) ------------------------------------- 36
Setting the Relay Operation (rely) -------------------------------------- 37
Relay and Alarm Operation ------------------------------------------------ 41
Pump Alternation Control Operation ------------------------------------- 46
Scaling the 4-20 mA Analog Output (Aout) ---------------------------- 47
Program the Sensor Break Output Value (SEbr) --------------------- 48
Analog Output when Display is Out of Range ------------------------- 48
Setting Up the Password (pass) ------------------------------------------- 49
Locking the Meter ------------------------------------------------------------ 49
Unlocking the Meter ---------------------------------------------------------- 49
Advanced Features Menu ---------------------------------------------------- 50
Advanced Features Menu & Display Messages ---------------------- 51
Offset Adjustment (Adj) ----------------------------------------------------- 53
Noise Filter (fltr) ------------------------------------------------------------ 53
Noise Filter Bypass (byps) ------------------------------------------------- 54
Serial Communications (serl) -------------------------------------------- 54
Protocol Selection Menu (Prot) ------------------------------------------ 54
Select Menu (SElc) ---------------------------------------------------------- 55
Linear or Square Root Function (linr or Sqrt) ---------------------- 55
Low-Flow Cutoff (cutF) ----------------------------------------------------- 56
Display Intensity (inty) ----------------------------------------------------- 56
Meter Copy Function (Copy) ----------------------------------------------- 57
Internal Calibration (ICal) -------------------------------------------------- 59
OPERATION ---------------------------------------------------------------- 62
Front Panel Buttons Operation -------------------------------------------- 62
Maximum/Minimum Readings ---------------------------------------------- 63
MOUNTING DIMENSIONS ---------------------------------------------- 64
TROUBLESHOOTING ---------------------------------------------------- 65
Diagnostics Menu (diag) ----------------------------------------------------- 65
Determining Software Version -------------------------------------------- 65
Reset Meter to Factory Defaults ------------------------------------------- 66
Factory Defaults & User Settings ----------------------------------------- 67
Troubleshooting Tips --------------------------------------------------------- 69
QUICK INTERFACE REFERENCE GUIDE ------------------------- 70
5
KOBOLD Model MPT Operating Instructions
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Table of Figures
Figure 1. Panel Cutout and Mounting ............................................... 14
Figure 2. Labeling for 2 Relay, Analog Out, & 24 V Supply Model . 15
Figure 3. Labeling for Analog Out & Two 24 V Supply Model ........ 15
Figure 4. Power Connections ............................................................ 16
Figure 5. Transmitter Powered by Ext. Supply or Self-Powered .... 16
Figure 6. Transmitters Powered by Internal Supply (Optional) ...... 17
Figure 7. Voltage Input Connections ................................................ 17
Figure 8. Thermocouple Input Connections .................................... 18
Figure 9. Three-Wire RTD Input Connections .................................. 18
Figure 10. Two-Wire RTD Input Connections ................................... 19
Figure 11. Four-Wire RTD Input Connections .................................. 19
Figure 12. Relay & 24 V Output Connections ................................... 20
Figure 13. AC and DC Loads Protection ........................................... 20
Figure 14. Low Voltage DC Loads Protection .................................. 21
Figure 15. 4-20 mA Output & Input Signal Powered by Meter ........ 22
Figure 16. 4-20 mA Output Powered Externally ............................... 22
Figure 17. Meter Copy Connection ................................................... 57
Figure 18. Meter Dimensions – Side View ........................................ 64
Figure 19. Case Dimensions – Top View .......................................... 64
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KOBOLD Model MPT Operating Instructions
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SPECIFICATIONS
Except where noted all specifications apply to operation at +25°C.
General
DISPLAY Standard: 0.56" (14 mm), Large Display: 1.20" (31 mm),
DISPLAY INTENSITY Eight intensity levels
DISPLAY
UPDATE RATE
OVERRANGE
UNDERRANGE
PROGRAMMING
METHODS
NOISE FILTER Programmable from 2 to 199 (0 will disable filter)
RECALIBRATION All ranges are calibrated at the factory. Recalibration is
MAX/MIN
DISPLAY
PASSWORD Programmable password restricts modification of settings.
NON-VOLATILE
MEMORY
POWER
OPTIONS
FUSE Required fuse: UL Recognized, 5 A max, slow blow
ISOLATED
TRANSMITTER
POWER SUPPLY
NORMAL MODE
REJECTION
ISOLATION 4 kV input/output-to-power line
OVERVOLTAGE
CATEGORY
Four digits (-1999 to 9999), automatic lead zero blanking.
Process/RTD: 3.7-5/second
Thermocouple: 1.8-2.5/second
Display flashes
Display flashes
Four front panel buttons, PC and MeterView® software, or
cloning using Copy function
recommended at least every 12 months.
Max/min readings reached by the process are stored until
reset by the user or until power to the meter is turned off.
All programmed settings are stored in non-volatile memory
for a minimum of ten years if power is lost.
85-265 VAC, 50/60 Hz
90-265 VD
or
12-36 VDC, 12-24 VAC, 6 W max
See table for power consumption
(*x: number depends on option)
Up to 6 meters may share one 5 A fuse
One or two transmitter power supplies (Optional)
P or P1: 24 VDC ± 10% @ 200 mA max. (-xxx1x)
P1 & P2: 24 VDC ± 10% @ 200 mA & 40 mA max. (-xxx2x)
64 dB at 50/60 Hz
500 V input-to-output or output-to-P1/P2 supplies
-6R5 & -6X5 models only: 100 V output-to-24 VDC supply
Installation Overvoltage Category II:
Local level with smaller transient overvoltages than Installation Overvoltage Category III.
C, 20
9999
-1999
W max
7
Model Watts
MPT-1x50x 8
MPT-1x5{1,2}x 20
MPT-1x30x 6
KOBOLD Model MPT Operating Instructions
DRAFT
ENVIRONMENTAL Operating temperature range: -40 to 65°C
CONNECTIONS Removable screw terminal blocks accept 12 to 22 AWG
ENCLOSURE 1/8 DIN, high impact plastic, UL 94V-0, color: gray
MOUNTING 1/8 DIN panel cutout required. Two panel mounting bracket
TIGHTENING
TORQUE
OVERALL
DIMENSIONS
WEIGHT 9.5 oz. (269 g) (including options)
WARRANTY 3 years parts & labor
Storage temperature range: -40 to 85°C
Relative humidity: 0 to 90% non-condensing
wire, RJ11 for serial communication adapters
assemblies provided
Screw terminal connectors: 5 lb-in (0.56 Nm)
2.45" x 4.68" x 4.19" (62 mm x 119 mm x 106 mm)
(H x W x D)
Process Input
INPUTS Field selectable:
ACCURACY ±0.05% of span ±1 count, square root: 10-100% FS
FUNCTION Linear or square root
LOW-FLOW
CUTOFF
TEMPERATURE
DRIFT
DECIMAL POINT Up to three decimal places for process inputs:
CALIBRATION
RANGE
INPUT
IMPEDANCE
INPUT
OVERLOAD
±20 mADC (0-20, 4-20 mA) and ±10 VDC (0-5, 1-5, 0-10 V)
0-9999 (0 disables cutoff function)
0 to 65°C ambient -40 to 0°C ambient
Current: ±0.20% FS (50 PPM/°C)
Voltage: ±0.02% FS (1.7 PPM/°C)
Current: ±0.80% FS
Voltage: ±0.06% FS
d.ddd, dd.dd, ddd.d, or dddd
An Error message will appear if input 1 and input 2 signals
are too close together.
Input Range Minimum Span
4-20 mA
±10 V
Voltage ranges: greater than 1 MΩ
Current ranges: 50 - 100 Ω
Current input protected by resettable fuse.
Fuse resets automatically after fault is removed.
Input 1 & Input 2
0.40 mA
0.20 V
(depending on resettable fuse impedance)
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KOBOLD Model MPT Operating Instructions
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Temperature Inputs
INPUTS Field selectable: type J, K, T, or E thermocouples;
RESOLUTION
ACCURACY
Input Type Range Accuracy
Type J
Type K
Type T
Type T
0.1° Res
Type E
100 Ω RTD
COLD
JUNCTION
REFERENCE
OFFSET
ADJUSTMENT
INPUT
IMPEDANCE
SENSOR BREAK
DETECTION
100 Ω platinum RTD (0.00385 or 0.00392 curve)
1° or 0.1° for all RTD inputs. 1° for all thermocouples.
1° or 0.1° for Type T thermocouple
(0 - 65 C)
-58° to 1382° F
-50° to 7
-58° to 2300° F
-50° to 1
-292° to 700° F
-180° to
-199.9° to 700.0°
-180.0° t
-58° to 1578° F
-50° to 8
-328° to 1382°
-200° to 750°C
Automatic, fixed, no user calibration needed
Programmable to ±19.9°. This parameter allows the user to
apply an offset value to the temperature being displayed.
Greater than 100 kΩ
Open TC or RTD sensor indicated by display flashing oPEn.
All relays and alarm status LEDs go to alarm or non-alarm
state, programmable for each relay individually.
Analog output goes to the programmed sensor break value.
50°
C
260°
C
371°
C
o 371.0°
70°
C
F
±2°F
±1°C
±2°F
±1°C
±2°F
±1°C
±1.8°F
F
C
±1.0°C
±2°F
±1°C
±1°F
±1°C
Accuracy
(-40 - 0 C)
±5°F
±3°C
±4°F
±2°C
±13°F
±7°C
±13°F
±7.2°C
±11°F
±6°C
±5°F
±3°C
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KOBOLD Model MPT Operating Instructions
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Relays Option
RATING 2 SPDT (Form C); rated 3 A @ 30 VDC or 3 A @ 250 VAC
ELECTRICAL
NOISE
SUPPRESSION
DEADBAND 0-100% of full scale, user selectable
HIGH OR LOW
ALARM
RELAY
OPERATION
RELAY RESET User selectable via front panel buttons or PC
TIME DELAY 0 to 199 seconds, on and off delays
FAIL-SAFE
OPERATION
AUTO
INITIALIZATION
resistive load; 1/14 HP @ 125/250 VAC (50 watts) for inductive loads
A suppressor (snubber) should be connected to each relay
contact switching inductive loads to prevent disruption to the
microprocessor’s operation.
Recommended suppressor value: 0.01 µF/470 Ω, 250 VAC
(PDX6901).
User may program any alarm for high or low trip point.
Automatic (non-latching)
Latching
Pump alternation control
Automatic reset only (non-latching)
Automatic + manual reset at any time (non-latching)
Manual reset only, at any time (latching)
Manual reset only after alarm condition has cleared (latching)
Automatic reset: Relays will automatically reset when the in-
put passes the reset point.
Manual reset: Front panel ACK button. Pressing ACK re-
sets all manually resettable relays.
Programmable and independent for each relay
Programmable
Independent for each relay
When power is applied to the meter, relays will reflect the
state of the input to the meter.
Fail-safe operation: relay coil is energized in non-alarm condition. In
case of power failure, relay will go to alarm state.
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KOBOLD Model MPT Operating Instructions
DRAFT
Isolated 4-20 mA Transmitter Output
OUTPUT RANGE 1.00 to 23.00 mA typical
CALIBRATION Factory calibrated for 4-20 mA
SCALING RANGE 0.00 to 23.99 mA for any display range,
ACCURACY ± 0.1% FS ± 0.004 mA
TEMPERATURE
DRIFT
ISOLATED
TRANSMITTER
POWER SUPPLY
EXTERNAL LOOP
POWER SUPPLY
OUTPUT LOOP
RESISTANCE
see output range above
0.4 uA/°C from -40 to 65°C ambient
Note: Analog output drift is separate from input drift.
One or two transmitter power supplies (Optional)
P1: 24 VDC ± 10% @ 200 mA max. (-1 option)
P1 & P2: 24 VDC ± 10% @ 200 mA & 40 mA max. (-2 option)
35 VDC maximum
Power supply Minimum Maximum
24 VDC
35 VDC (external)
10 Ω
100 Ω
700 Ω
1200 Ω
Serial Communications
METER
ADDRESS
BAUD RATE 300 – 19,200 bps
TRANSMIT
TIME DELAY
DATA 8 bit (1 start bit, 1 stop bit)
PARITY None (1 or 2 stop bits), even, or odd
BYTE-TO-BYTE
TIMEOUT
TURN AROUND
DELAY
Refer to PDC and Modbus Serial Communication Protocol manuals for
details. These can be downloaded from: www.koboldusa.com.
PDC protocol: 0 - 99
Modbus protocol: 1 - 247
Programmable between 0 and 199 ms
(Modbus only; PDC protocol does not use parity)
0.01 – 2.54 sec (Modbus only)
Less than 2 ms (fixed)
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KOBOLD Model MPT Operating Instructions
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COMPLIANCE INFORMATION
Safety
UL LISTED USA and Canada
UL FILE NUMBER E160849
FRONT PANEL UL Type 4X, NEMA 4X, IP65; panel gasket provided
LOW VOLTAGE
DIRECTIVE
Electromagnetic Compatibility
EMISSIONS
Radiated
Emissions
AC Mains
Conducted
Emissions
IMMUNITY
RFI - Amplitude
Modulated
Electrical Fast
Transients
Electrostatic
Discharge
RFI - Conducted
AC Surge
Surge
Power-Frequency
Magnetic Field
Voltage Dips
Voltage
Interruptions
UL 508 Industrial Control Equipment
EN 61010-1:2010
Safety requirements for measurement, control, and laboratory use
EN 55011:2009 + A1:2010
Group 1 Class A ISM emissions requirements
Class A
Class A
EN 61326-1:2013
Measurement, control, and laboratory equipment
EN 61000-6-2:2005
EMC heavy industrial generic immunity standard
80 -1000 MHz 10 V/m 80% AM (1 kHz)
1.4 - 2.0 GHz 3 V/m 80% AM (1 kHz)
2.0 - 2.7 GHz 1 V/m 80% AM (1 kHz)
±2kV AC mains, ±1kV other
±4kV contact, ±8kV air
10V, 0.15-80 MHz, 1kHz 80% AM
±2kV Common, ±1kV Differential
1KV (CM)
30 A/m 70%V for 0.5 period
40%V for 5 & 50 periods
70%V for 25 periods
<5%V for 250 periods
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KOBOLD Model MPT Operating Instructions
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Note:
Testing was conducted on MPT Meters installed through the covers
of grounded metal enclosures with cable shields grounded at the
point of entry representing installations designed to optimize EMC
performance.
Declaration of Conformity available at www.koboldusa.com
SAFETY INFORMATION
!
CAUTION: Read complete
instructions prior to installation and operation of the
meter.
WARNING
Hazardous voltages exist within enclosure. Installation and service
should be performed only by trained service personnel.
WARNING: Risk of
electric shock.
13
KOBOLD Model MPT Operating Instructions
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INSTALLATION
There is no need to remove the meter from its case to complete the installation, wiring, and setup of the meter.
Unpacking
Remove the meter from box. Inspect the packaging and contents for damage. Report damages, if any, to the carrier.
If any part is missing or the meter malfunctions, please contact
your supplier or the factory for assistance.
Panel Mounting
• Prepare a standard 1/8 DIN panel cutout – 3.622" x 1.772" (92 mm
x 45 mm). Refer to MOUNTING DIMENSIONS, page 64 for more
details.
• Clearance: allow at least 4" (102 mm) behind the panel for wiring.
• Panel thickness: 0.04" - 0.25" (1.0 mm - 6.4 mm).
Recommended minimum panel thickness to maintain Type 4X
rating: 0.06" (1.5 mm) steel panel, 0.16" (4.1 mm) plastic panel.
• Remove the two mounting brackets provided with the meter (back-off
the two screws so that there is ¼" (6.4 mm) or less through the
bracket. Slide the bracket toward the front of the case and remove).
• Insert meter into the panel cutout.
• Install mounting brackets and tighten the screws against the panel.
To achieve a proper seal, tighten the mounting bracket screws
evenly until meter is snug to the panel along its short side. DO NOT
OVER TIGHTEN, as the rear of the panel may be damaged.
Figure 1. Panel Cutout and Mounting
14
KOBOLD Model MPT Operating Instructions
DRAFT
Connections
All connections are made to removable screw terminal connectors
located at the rear of the meter.
Use copper wire with 60°C or 60/75°C insulation
for all line voltage connections. Observe all safety
regulations. Electrical wiring should be performed
in accordance with all applicable national, state,
and local codes to prevent damage to the meter
and ensure personnel safety.
Connector Labeling
The connectors label, affixed to the meter, shows the location of all connectors available with requested configuration. It also identifies the location of the RTD/TC selector switch. The below two images are common
connector configurations for the MPT. Note that the connector in the upper left of the diagram has two different configurations based on the
model.
RELAY2 RELAY1
4
6 5
3
COM NONO NC NC COM
RTD
TC
EXC T+ V+ mA+ COM
3 41 2 5
SIGNAL
2 1
RTD
SWITC H
24V OUT
2 1
P+ P-
1 2 3 4 5 6
TC
SERIAL
mA OUT
6 5
I
-I +
POWER
2 1
+
DW2206
Figure 2. Labeling for 2 Relay, Analog Out, & 24 V Supply Model
Figure 3. Labeling for Analog Out & Two 24 V Supply Model
15
KOBOLD Model MPT Operating Instructions
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Power Connections
Power connections are made to a two-terminal connector labeled
POWER on Figure 2. The meter will operate regardless of DC polarity
connection. The + and - symbols are only a suggested wiring convention.
POWER CONNECTOR
12
+-
AC or DC
Required External Fuse:
5 A max, Slow Blow
Figure 4. Power Connections
Signal Connections
Signal connections are made to a five-terminal connector labeled
SIGNAL on Figure 2. The COM (common) terminal is the return for all
types of input signals.
Current and Voltage Connections
The following figures show examples for current and voltage connections.
There are no switches or jumpers to set up for current and voltage inputs.
Setup and programming is performed through the front panel buttons.
POWER
Figure 5. Transmitter Powered by Ext. Supply or Self-Powered
16
KOBOLD Model MPT Operating Instructions
DRAFT
Figure 6. Transmitters Powered by Internal Supply (Optional)
The current input is protected against current overload by a resettable
fuse. The display may or may not show a fault condition depending on
the nature of the overload.
The fuse limits the current to a safe level when it detects a fault condition, and automatically resets itself when the fault condition is removed.
Figure 7. Voltage Input Connections
The meter is capable of accepting any voltage from -10 VDC to +10 VDC.
17
KOBOLD Model MPT Operating Instructions
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Thermocouple and RTD Connections
The following figures show examples for thermocouple and RTD connections.
The RTD/TC selector switch must be set to the proper position for the
meter to accept the selected temperature input.
The input type is selected using the Setup menu.
Selected thermocouple input must correspond to thermocouple sensor
and wire type used.
Figure 8. Thermocouple Input Connections
Figure 9. Three-Wire RTD Input Connections
T
he meter accepts two, three, or four-wire RTDs. The three-wire RTD
connection has built-in lead wire compensation.
18
KOBOLD Model MPT Operating Instructions
DRAFT
Figure 10. Two-Wire RTD Input Connections
Lead wire compensation for two-wire RTDs can be applied using the
Adjust menu. See Offset Adjustment (Adj), page 53.
Figure 11. Four-Wire RTD Input Connections
The four-wire RTD connection is similar to the three-wire. One of the
leads of a four-wire RTD is not connected, and may be clipped off.
The three-wire connection provides sufficient lead wire compensation to
provide accurate readings even with long leads.
19
KOBOLD Model MPT Operating Instructions
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Serial Communication
Serial communication connection is made to an RJ11 connector labeled
SERIAL on Figure 2. Use PDA7232 for RS-232 interfacing.
Use PDA7422 for RS-485 interfacing.
Use PDA7420 for meter-to-meter interfacing for cloning purposes (i.e.
copying programmed settings from one meter to other meters).
Relays and 24 V Output Connections
Relay connections are made to a six-terminal connector labeled
RELAY1, RELAY2 on Figure 2. The COM (common) terminals of the relays should not be confused with the COM (common) terminal of the
SIGNAL connector. The 24 VDC output is available at the connector labeled 24V OUT, next to the relays connector.
Figure 12. Relay & 24 V Output Connections
Switching Inductive Loads
The use of suppressors (snubbers) is strongly recommended when switching inductive loads to prevent disrupting the microprocessor’s operation. The suppressors also prolong the life of the relay contacts. Suppression can be obtained with
resistor-capacitor (RC) networks assembled by the user or purchased as complete assemblies. Refer to the following circuits for RC network assembly and installation:
C
C
R
Figure 13. AC and DC Loads Protection
20
R
KOBOLD Model MPT Operating Instructions
DRAFT
Choose R and C as follows:
R: 0.5 to 1 Ω for each volt across the contacts
C: 0.5 to 1 µF for each amp through closed contacts
Notes:
1. Inductive relay rating is 1/14 HP (50 W) at 115/230 VAC
2. Use capacitors rated for 250 VAC
RC networks may affect load release time of solenoid loads. Check to con-
3.
firm proper opera
4.
Install the RC network at the meter's relay screw terminals. An RC ne
may also be installed across the load. Experiment for best results.
Figure 14. Low Voltage DC Loads Protection
RC Networks Available from KOBOLD
RC networks are available from KOBOLD and should be applied to each relay
contact switching an inductive load. Part number: PDX6901.
Note:
Relays are de-rated to 1/14th HP (50 watts) with an inductive load.
tion.
.
twork
Use a diode with a reverse
breakdown voltage two to
three times the circuit voltage and forward current at
least as large as the load
current.
21
KOBOLD Model MPT Operating Instructions
DRAFT
4-20 mA Output & Input Signal Connections
Connections for the 4-20 mA transmitter output are made to the connector terminals labeled “mA OUT, I-, I+”. The 4-20 mA output may be
powered from an internal power supply (optional) or from an external
power supply.
SIGNAL CONNECTOR
mA+
V+ T+
EXC
21 354
COM
mA OUT
I-
6
I+
24V OUT
P1-
45 312
P2+
P2-P1+
-
2-Wire
4-20 mA
Transmitter
+
Remote Display,
Chart Recorder,
etc.
-
+
Figure 15. 4-20 mA Output & Input Signal Powered by Meter
mA OUT
I-
I+
56
External
Power
Supply
-
+
+
Remote Display,
Chart Recorder,
etc.
Figure 16. 4-20 mA Output Powered Externally
-
22
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