weschler instruments OMBGP100 User manual

ACP4 BarGraph Watt & Var Meters
Owners Manual
Manual Part Number OMBGP100
Revision 1, June, 2006
16900 FOLTZ PARKWAY, CLEVELAND, OHIO 44149
440/238-2550, FAX [phone] e-mail: [email protected]

Table of Contents
Title Section Page
Introduction .................................... 1.0..................................... 1
Description
Intended Usage
Models and Features
ReceiptInspection .............................. 2.0..................................... 4
Installation .................................... 3.0..................................... 4
Connections, Power Requirements & Fuse Ratings
Mounting and Terminal Assignments
Configuration .................................. 4.0..................................... 9
Keystroke-by-keystroke Set Up Guide
Supervisory Setup, Keystroke Diagrams
Operation ..................................... 5.0.....................................14
Calibration .................................... 6.0.....................................16
Troubleshooting ................................ 7.0.....................................18
Specifications .................................. 8.0.....................................21
Warranty...................................... 9.0.....................................23
Figures
1. Display and Controls ................................................................ 2
2.TerminalAssignments ............................................................... 3
3. Base Terminal and Fuse Location (standard base) ......................................... 3
4. Interfacing a PC for RS-485 Communications with Multiple BarGraphs ......................... 6
5. Signal Connections (5A - 5J) ......................................................... 7-8
6.JumperLocations................................................................... 9
7. Supervisor Mode Configuration Keystroke Diagram (7A & 7B) ................................13
8. Operator Mode Keystroke Diagram .....................................................15
9. Single Phase Test Connections ........................................................16
10. Outline, Cutout and Drilling (3A - 3C) ..................................................22
Tables
1.FeatureComparisonSummary ........................................................ 2
2.RelayContactRatings............................................................... 5
3. Fuse Ratings (3A Standard, 3B Enhanced, 3C TriColor) ....................................18
4. Connection Error Symptoms (4A- 3P 3W; 4B- 3P 4W) ......................................19
5Specifications ......................................................................21

1.0 Introduction
Description
The ACP4 BarGraph watt and var meters are part of the ACP4 series of AC power instruments, comprising voltmeter,
ammeter, watt meter, var meter and power factor functions. The instruments in the series are driven by the latest state of
the art technology, utilizing a digital signal processing (DSP) IC for power measurement and conversion and a
microprocessor for function coordination, configuration, communications and display presentation.
Intended Usage
TheACP4seriesinstruments are intended forusewhereverthere exists a needformeasurementsofACpowerquantities
of high accuracy and reliability in an industrial quality switchboard instrument. Some models are available in military
ruggedized and spray-tight versions; consult the factory for availability of these models.
In existing applications, the Weschler ACP4 series watt and varmeters are intended to replace analog instruments such
as the Weschler or Westinghouse KP-241 and KP-261, KV-241 and KV-261 and the GE / Yokogawa AB40. In new
applications the ACP4 series is ideally suited where an increased level of functionality is desired.
Models and Features
The watt and var models are identified by the three character prefix BGP ( watt meter), BGG ( var meter for use with a
phase shifting transformer) or BGV (var meter for use without a phase shifting transformer). The ACP4 series is available
in standard switchboard sizes identified by the three digit suffix 241 ( 4 ½ inch square ), 251 ( 7 ½ inch round ) 261( 8
¾ inch square) and 281 ( 10 inch round ). All sizes are available in the standard and enhanced display configurations.
TriColor versions are available in 241, 261 and 281 sizes. Standard, Enhanced and TriColor models are primarily
differentiated by their display presentation, although the feature set becomes more flexible from standard to TriColor
models.
The standard BarGraph is available with a red, green or amber numeric display with a measurement range of -19999 to
+19999 counts. The standard bar color is red. Fixed position color zones are possible in the bar display, but brightness
ofthe green andamber colors maybea problem inareas wherehigh ambient lightintensity exists. Itisrecommended that
if color zones are required in the bar, that the enhanced or TriColor models be considered.
The Enhanced model is available with red, green or amber color numeric displays with a measurement range of -9999 to
+50000 counts. The standard red bar color is a very bright, sunlight readable intensity. The bar display can be a solid red,
green or amber, or mixed, fixed-position color zones. The amber and green colors are suitable for high ambient lighting
intensity, but may not be suitable for sunlight readability. The enhanced models also has a dual-level display brightness
setting that is programmable from the front panel buttons.
The TriColor model is available with a red, green oramber numeric display witha measurement range of ± 50000 counts.
Thebar display canbe programmed for zoned orbanded patterns,with contrasting set pointsthat delineate theboundary
ofthebandsorzones.Byprogrammingthefoursetpointvalues,thebarmaybesettochangecolorsatdifferentmeasured
signalmagnitudes, insuringthatoperators areinstantlyaware ofoperationwithin oroutsideof normal boundaries,without
reading the actual value.
OMBGP100 Rev 1 Page 1 of 23

Figure 1. Standard ACP4 BarGraph Dial and
Front Panel Features
Figure 2. Enhanced and TriColor ACP4
BarGraph Dial and Front Panel Features
Enter / Save Button
Decrement Button
Increment Button
Table 1. Feature Comparison Summary
Feature BGP Wattmeters, BGG and BGV Varmeters
Standard Enhanced TriColor
Measurement Range ± 19999 -9999 to 50000
(Neg Autoscale) ± 50000
Basic Accuracy ± 0.5% FS, ± 1 Count ± 0.5% FS, ± 1 Count ± 0.5% FS, ± 1 Count
Potential Range 120, 240 vrms 120, 240 vrms 120, 240 vrms
Self-Contained Current Maximum 10.00 arms 10.00 arms 10.00 arms
Numeric Display Characters 4 ½ Digit 4 ¾ Digit 4 ¾ Digit
Numeric Display Colors Red, Green, Amber Red, Green, Amber Red, Green, Amber
Bar Colors Red, Green, Amber (note 1) Red, Green, Amber Red, Green, Amber
Bar Color Arrangement Fixed Zones Fixed Zone Programmable Zone or Band
Display Brightness Fixed Two Level Programmable 16 Level Programmable
Alarm Hysteresis 0.5, 1 & 2 % FS for All Alarms 0.0-10.0% FS for All Alarms 0.00-10.00 % FS for All Alarms
Relays 2 OR 4 Form C 2 OR 4 Form C 2 OR 4 Form C
Relay Latching N/A Yes Yes
HI - LO Alarms 2 HI, 2 LO Individually Programmable Individually Programmable
Analog Retransmit 256 Step Resolution 65000 Step Resolution 65000 Step Resolution
Communications RS-232 or 485 RS-232 or 485 RS-232 or 485
Decreasing Trend Annunciator 51 Segment Bar Display
Increasing Trend Annunciator
Alarm 3 Lo Annunciator Alarm 2 Hi Annunciator
Alarm 4 LoLo Annunciator Alarm 1 HiHi Annunciator
4 ½ Digit Numeric Display
OMBGP100 Rev 1 Page 2 of 23

Decreasing Trend Annunciator
Alarm 3 Annunciator
Alarm 4 Annunciator
Enter/ Save Button Increment button
Decrement Button
Wickman type 374/TR5 Time Lag Fuse.
Note relationship of pins to the line marked
on the fuse body.
Communications Wiring
Terminal RS-232 RS-485
1TX-
2 COM GND
3RX+
Figure 3. Base Terminal and Fuse Location
(standard base)
Increasing Trend Annunciator
Alarm 2 Annunciator
Alarm 1 Annunciator
4 ¾ Digit Numeric Display
Relay, Retransmit and Communications
Connectors are Phoenix-Type. Plugs are
Furnished if These Options are Ordered.
#6-32 Screw Terminals
OMBGP100 Rev 1 Page 3 of 23

2.0 Receipt Inspection
Packaging Inspection
The packaging in which your BarGraph is shipped is designed to protect its contents against normal shipping shock and
vibration. If the external carton is damaged in any way, report any damage to the carrier as soon as possible and
immediately unpack the carton for internal inspection.
Unpacking
The BarGraph is packaged with this manual, a software manual if equipped with digital communications, a mounting
hardware kit, Phoenix-type plugs for mating with installed option connectors and a spare fuse. Other accessories such as
calibration tools, or other items which may have been ordered at the same time will be included only if the packaging
integrity is not compromised. Please remove all packing materials and check them for included accessories before
discarding them.
Physically inspect the BarGraph and its accessories for signs of hidden shipping damage. Evidence of excessive
roughnessinshippingincludeadentedcaseandcrackeddisplaywindows.Shaketheinstrumentandlistenforanyrattling
which would indicate parts adrift inside the case.
3.0 Installation
All signal and power connections are made to the terminal strips (standard base) or terminal studs (molded base). The
molded base is primarily supplied for compatibility with Weschler and Westinghouse analog instruments. The number of
terminalstudsavailableinthemoldedbasearelimitedbyspaceconstraints,andterminalassignmentsarethereforemade
depending upon the options ordered. See figure 6A - 6Z for option connections when the molded base is supplied.
On the Standard base, alarm relay, analog re-transmit and communications connections are made through Phoenix style
receptacles and plugs rated for 300v, 8 amp service. The plugs are provided in the installation kit for the receptacle
correspondingtoanordered option. Additionalorreplacement plugsare available fromWeschlerorelectroniccomponent
supply companies according to the following table:
Receptacle Weschler Part Number Manufacturer Mfg Part Number
Retransmit 2100003602 Phoenix 1803426
Relay 2100003612 “ 1803439
Communications 2100003603 “ 1803523
Analog Retransmit Connections
The analog retransmit output is available in two forms; PWM and DAC. The PWM style, supplied only on the standard
ACP4 BarGraph, is a constant voltage type with 256 step resolution. It is available in isolated and non-isolated versions.
Because the voltage is proportional to the signal, the loop resistance, including the load and lead resistance, must be
carefully calculated in order to maintain the accuracy of the output current. If the loop resistance varies from the specified
value,theoutputcurrentwillhaveaproportionalerror.Normallywhenusingthistypeofoutput,theloopresistanceisbelow
the value specified and it is padded up to the required value with an external resistor.
The DAC retransmit is supplied on the Enhanced and TriColor ACP4 BarGraphs. It is a constant current type with 65000
step resolution. It is available in isolated output only. The constant current output means that the output will be unaffected
by loop resistance within the loop resistance limits of 0 to 1000 ohms. This type of retransmit is configurable through front
panel programming buttons for any current between 0 and 24 ma corresponding to any on-scale signal span. The output
is not bipolar, however; if can only produce positive current values.
On both output types, 20 to 24 AWG, 300 volt, 105 EC hook up wire is recommended.
OMBGP100 Rev 1 Page 4 of 23

Alarm Relay Connections
The alarm relay contacts are rated for 5 amps maximum, and the hook-up wire should be selected accordingly. The
potential rating of the relay contacts is related to the current rating as shown in table 2.
Table 2. Relay Contact Ratings
Contact Current Rating ...........@ ........... PotentialRating Load
NO 5A.................................. 30vdc Resistive
5A............................... 120 / 240 vac “
1/14HP.............................. 120/240 vac Inductive
NC 5A.................................. 30vdc Resistive
5A............................... 120 / 240 vac “
1/10HP............................. 120 / 240 vac Inductive
It is recommended that insulation be selected with a minimum 600 v, 105 EC rating.
Signal and Power Connections
Theterminalstripsused in ACP4 BarGraphareratedfor20 amps,250volts rms. Theterminalscrewsshouldbe tightened
to 8 - 11 inch pounds. The maximum torque on the screws, without thread damage, is 13 inch pounds. Lead terminating
lugs must be suitable for #6-32 terminal screws with a maximum lug width of 5/16 (0.312) inches. Actual connection
diagrams are presented in figure 5 below.
Current Circuits
CAUTION! CAUTION!
Special attention must be taken when wiring to the current sense circuit if it is connected directly to a current
transformer (CT), since the open secondary of a CT can generate high voltages which are lethal to personnel.
Precautions must be taken to either de-energize the current circuit (preferred) or short circuit the CT secondary before
making any wiring changes. Consult with your safety personnel for appropriate practice prior to making any current circuit
connections.
The BarGraph’s current circuits have ratings up to 10 amps maximum continuous, though the actual rating of your
BarGraph may be less. The BarGraph current circuits are designed to withstand the 1000% momentary current overload
and 120% sustained current overload specified in ANSI C39.1-1981, and the terminal lugs and hook-up leads must be
capable of carrying this current as well, if the C39.1 overload is required. It is recommended that the wire have a 600 volt,
105 EC insulation rating. Consult national and local wiring standards for actual wiring requirements.
Potential Circuits
The BarGraph potential circuits are ultra low burden circuits which draw less than 1 ma of compliance current. Although
this current is very low, it is recommended that the external wiring be 20 AWG or greater diameter with a 600 volt, 105 EC
insulation rating. Consult national and local wiring standards for actual wiring requirements.
Power Circuit
The BarGraph can be powered from the power sources listed in table 2. The maximum compliance current (825 ma) of
all BarGraph ACP4 instruments is drawn by the TriColor instrument at the 12 vdc source voltage level with maximum
brightness, full amber bar and all relays picked up. All other instruments in the BarGraph ACP4 series draw less current.
Itisrecommendedthattheexternalwiringbe20AWGorgreaterdiameterwitha600volt,105ECinsulationrating.Consult
national and local wiring standards for actual wiring requirements.
OMBGP100 Rev 1 Page 5 of 23

COMPUTER
COMMPORT
DB-9CONNECTOR
RS-232 TO RS-485
CONVERTER
TX
RC
RTS
GND
2
3
4
7
2
3
7
5
TX-
TX+
RC-
RC+
GND
BarGraph
WITH UNIT
ID SET TO
00
1(-)
2
3(+)
COMM PORT
BarGraph
WITH UNIT
ID SET TO
01
1(-)
2
3(+)
COMM PORT
BarGraph
WITH UNIT
ID SET TO
99
1(-)
2
3(+)
COMMPORT
UNIT IDS CAN
RANGE FROM
00 TO 99
R1
R1
R1
R1
R2
R2
2
5
14
17
7
DB-25 CONNECTORS
EXTERNAL
POWER
SUPPLY
Figure 4. Interfacing a PC for Digital Communications with Multiple BarGraphs
Digital Communications Connections
The ACP4 series BarGraphs support full duplex RS-232 and half-duplex (2-wire), multidrop RS-485 communications.
For RS-232 applications, BarGraph comm connector terminal 1 (transmit) is connected to the host’s receive terminal and
BarGraph comm connector terminal 3 (receive) is connected to the host’s transmit terminal. The BarGraph comm
connector terminal2 (common)is connectedto thehost’s commonterminal.The commonterminalis notanearth ground
connection. It is intended as a signal reference between the BarGraph and the host only.
For RS-485 applications, BarGraph comm terminal 1 (-) is connected to the host’s (-) terminal and BarGraph comm
terminal 3 (+) is connected to the host’s (+) terminal. The BarGraph comm connector terminal 2 (common) may or may
not be necessary for system operation. It is normally used to suppress common mode voltage on the two active lines.
When it is required to be connected, it is recommended to add a 100 ohm resistor in series with the host in order to limit
surgecurrents.TheRS-485standardallows32devicestobeconnectedtothesamepairoflines.Inmultidropinstallations
it may be necessary to connect a 125 ohm resistor across the terminals of the last device in the string in order to suppress
signal reflection. It is recommended that the system be operated without the resistor and ad it only if the system operates
unsatisfactorily.
A common communications circuit which is used to interface a PC to BarGraph and other RS-485 devices, employs an
RS-232 to RS-485 converter, as illustrated in Figure 4. In this diagram, the user is communicating with three BarGraphs,
each with its own unique comm identification number.
Notes for Figure 4
1. The computer, converter, cabling and resistors shown are user supplied.
2. Add 100 ohm resistors (R1) between the signal ground of the converter and terminal 2 of each BarGraph.
3. Add120ohmresistors(R2)attheoutputoftheconverterandacrosstheterminalsofthelast BarGraphonthebranch.
4. Upto32BarGraphsmaybeconnectedtoacommonRS-485branchcircuit.EachBarGraphmusthaveitsownunique
unitID,selectedfromarangeof00to99 hex (153 decimal). Note thattheBarGraphdisplayshowsunitID'sasdecimal
numbers, but the actual protocol uses hex numbers. The decimal number shown on the display must therefore be
converted to hex in order for the host to correctly address the BarGraph.
OMBGP100 Rev 1 Page 6 of 23

Figure 5D. 1 Phase 2 Wire Type
BGP Wattmeter and BGV
Varmeter with Molded Base
Connection Diagrams
Thediagramsbelowpresent all common powermeasurementschemes. The alarmrelay,communicationsandretransmit
connections are omitted, since these are well known circuits or have been described above.
Figure 5C. 3 Phase 4 Wire Type
BGP Wattmeter & BGV Varmeter
Figure 5B. 3 Phase 3 Wire Type
BGP Wattmeter & BGV Varmeter
Figure 5E. 3 Phase 3 Wire Type
BGP Wattmeter and BGV
Varmeter with Molded Base
Figure 5A. 1 Phase 2 Wire Type
BGP Wattmeter & BGV Varmeter
Figure 5F. 3 Phase 4 Wire Type
BGP Wattmeter and BGV Varmeter
with Molded Base
OMBGP100 Rev 1 Page 7 of 23

Figure 5I. 3 Phase 4 Wire, 3 PT
Type BGV Varmeter
Figure 5G. 3 Phase 4 Wire Type BGG
Varmeter for Use with Phase Shifting
Transformer
Figure 5H. 3 Phase 4 Wire Type BGG
Varmeter with Molded Base for Use with
Phase Shifting Transformer
The following connections are less common, but are supported by APP-4 BarGraphs:
Figure 5J. 3 Phase 4 Wire, 3 PT
Types BGP & BGV Wattmeter &
Varmeter with Molded Base
OMBGP100 Rev 1 Page 8 of 23