TDI MCL488 Series Owner's manual

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1CD1POWER
MCL488 Series
Electronic Loads
Operation & Programming Manual
TDI-Dynaload® Division
Document Number 403606Revision A

©2004 TDI-Dynaload — All Rights Reserved.
The copyright laws of the United States and other countries protect this material. It may not be
reproduced, distributed, or altered in any fashion without the expressed written consent of TDI-Transistor
Devices, Inc.
Disclaimer
The contents of this document, including all specifications, are subject to change without notice.
Mandatory Customer Information
Federal Communications Commission (FCC) Statement
NOTE: This equipment has been tested and found to comply with the limits for a Class A digital device,
pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against
harmful interference when equipment is operated in a commercial environment. This equipment
generates, uses, and can radiate radio frequency energy; and, if not installed and used in accordance with
the instruction manual, may cause interference to radio communications. Operation of this equipment in a
residential area may cause harmful interference in which case the user will be required to correct the
interference at their expense.
Trademarks
Dynaload is a registered trademark of Transistor Devices, Inc.
Ordering Information
The ordering number for this document is 402825. To order this document, contact:
TDI-Dynaload Division
36A Newburgh Road
Hackettstown, NJ 07840
Telephone: [phone]
Facsimile: [phone]
Online Availability
To find out more about TDI and our products, visit us on the web at: http://www.tdipower.com/ or visit
TDI-Dynaload directly at: http://www.tdipower.com/dynaload/.
Customer Services
For technical assistance regarding our products, contact the following:
Sales Inquires
Dynaload Sales Manager
Telephone: [phone]
Facsimile: [phone]
Customer Service and Repairs
Dynaload Customer Service Department
Telephone: [phone]
Facsimile: [phone]
2

TABLE OF CONTENTS
Revision A
09/16/05
Introduction 6
Protective Circuits 7
Current Limit7
Power Limit7
Overvoltage7
Reverse Polarity 7
Undervoltage Lockout7
Front Panel Operation8
Electrical Connections
Ter min al Identification 9
Ter min al Block9
IEE E-488/RS232 (optional) 9
E+ and E- Wiring Tips9
AC Input 9,11
Effects of Cable Length10
Current Oscillation 10
Line Loss10
S+ and S- Wiring Tips10
Link 11
PGM11
CS 11
Ter min al Block Connections12
Operating Instructions
Constant Current Mode13
Constant Resistance Mode14
Constant Voltage Mode14
Constant Power Mode14
Local Control 14
Remote Programming14
Short Circuit 15
Manual Adjust Knob15
Slave Mode15
MEM- Memory Recall 15
Menu Commands16
Slew Rate Adjustment16
IEEE Address Setting 16
Encoder Resolution Setting 16
Knob Resolution for Time17
Knob Resolution for Frequency17
Front Panel Lock17
Password Change17

Amps/ Volts or Ohms17
Ter min ato r 17
Number of Pulses17
Memory Set18
Short Enable18
Pulse Amplitude, Absolute or Delta18
Undervoltage Lockout18
Pulse Train 18
System Wide DC ON/OFF Control 19
Scale Factor19
Fault Indicators19
Pulse Loading 20
Manual Operation21
IEEE-488 Programming22
Effects of Cable Inductance on Pulse Loading23
Transconductance24
Linking Modules 25
Location, Airflow and Maintenance26
Operator Safety Instructions27
IEEE-488 Programming Introduction28
IEEE-488 Bus Subsets29
Data Separators30
Program Line Terminators30
Numerical Data Formats31
Numerical Data Units32
Power On Defaults33
Command Description34
Query Description 34
Syntax35
Load Operating Modes35
Pulse Parameters35
Relay Control36
Misc. Commands36
Readbacks36
Queries37
Language Elements (command listing with complete descriptions) 38
AV1 (base resistance A/V pulse mode)39
AV2 (peak resistance A/V pulse mode)39
AV3 (peak resistance 3 A/V pulse mode)39
AVH (constant resistance high, A/V mode)40
AVL (constant resistance low, A/V mode)40
CH (channel setting)40
CI (constant current setting) 41
CP (constant power setting)41
CRH (constant resistance high, ohms mode)42
CRL (constant resistance low, ohms mode)42
CV (constant voltage setting) 43
DU (duty cycle setting) 43
D2 (duty cycle setting) 44

D3 (duty cycle setting) 44
FQ (frequency setting) 45
11 (constant current base setting) 45
12 (constant current peak setting) 46
13 (constant current peak setting)46
LAT (set latched fault mask)47
LOAD OFF 48
LOAD ON 48
LOCK OFF (front panel lockout) 48
LOCK ON (front panel lockout) 49
MR (memory recall)49
MS (memory set)49
P1 (constant power base setting)50
P2 (constant power peak setting) 50
P3 (constant power peak 3 setting) 51
PAA (ABSOLUTE pulse amplitude)51
PAD (DELTA pulse amplitude) 51
PS ON (synchronous pulse enable52
PS OFF (synchronous pulse disable52
R1 (base resistance ohms pulse mode)52
R2 (peak resistance ohms pulse mode)53
R3 (peak resistance 3 ohms pulse mode)53
REC (memory recall) 54
RST (reset)54
51 (slew rate rise time)54
S2 (slew rate fall time)55
SBE (set summary bit enable register)56
SDN (set shutdown mask)57
SRQ (set IEEE-488 bus SRQ mask)58
SF (scale factor) 59
SHORT OFF59
SHORT ON 60
SLAVE OFF 60
SLAVE ON 60
SR (slew rate setting)61
SUV OFF (system undervoltage lockout) 61
SUV ON 61
SW (pulse generator on)62
SYS (System-wide control) 62,63
T1 (time duration 1)63
T2 (time duration 2)63
T3 (time duration 3)64
TEXT OFF 64
TEXT ON 64
TP OFF (Three level pulse) 65
TP ON (Three level pulse) 65
UV (undervoltage lockout)65,66
UVP (programmable undervoltage lockout)66
V1 (base voltage. pulse mode)67

V2 (peak voltage. pulse mode)67
V3 (peak voltage 3, pulse mode)68
WF (pulse mode on)68
XM (external modulation) 69
*RST (reset)69
Status & Error Registers70
Condition, Latch, Shutdown and Summary Bit Enable71
Error 71
Load Status Logic Diagram72
CON? (query load's condition register)73
ERR? (query load's error register)74
ID? (Unit ID query)74
MODE? (report load's operating mode)75
STA? (report contents of status register) 76
VER? (software version query)76
*IDN? (query load identification)76
Mechanical DrawingsAppendix A
Specifications Appendix B
6

INTRODUCTION
The Dynaload is a precision instrument which simulates DC loads to test power
supplies, generators. servo systems, batteries and similar DC sources.
The MCL488 series provides up to ten load channels housed in a single chassis. Each
load channel is fully independent, operating in one of four modes: Constant Current,
Constant Resistance, Constant Voltage and Constant Power. Complete control of any
channel is available through the full feature front panel, IEEE-488 bus or optional
RS232 interface. A 0-10V analog programming input is also available for each channel
in all of the four modes of operation. The connections for IEEE-488 and analog
programming are located at the rear of the unit. The four modes of operation are
outlined below:
I
LOAD
CURRENT
SLOPE
RESISTANCE
SETTING
INPUT VOLTAGE
CONSTANT RESISTANCE MODE
V
INPUT
VOLTAGE
VOLTAGE
SETTING
•
LOAD CURRENT
CONSTANT VOLTAGE MODE
LOAD
CURRENT
I
LOAD
CURRENT
CURRENT
SETTING
• INPUTVOLTAGEV
CONSTANT CURRENT MODE
CONSTANT POWER
SETTING
INPUT VOLTAGE V
CONSTANT POWER MODE
CONSTANT CURRENT
The Dynaload will sink the set current regardless of the input voltage.
CONSTANT RESISTANCE
The Dynaload will sink current linearly proportional to the input voltage. This is set in
Amps/Volt, (1/R), or ohms.
CONSTANT VOLTAGE
The Dynaload will sink the current required to maintain the voltage of the source
connected to it.
CONSTANT POWER
The Dynaload will sink the current required at its present input voltage to maintain the
desired power level.
7

PROTECTION CIRCUITS
CURRENT LIMIT:
Each load channel is protected from drawing excessive current beyond its rating. The
factory set point is 65 Amps. This is not a user settable function and serves to protect
the load module only. This limit acts as an absolute barrier and will not permit the
current to increase beyond the setpoint. An alarm warning is illuminated on the front
panel if the limit is achieved.
POWER LIMIT:
Each load channel is protected against operation at power levels beyond its rating. The
power level is factory set at 365 Watts. This is not a user settable function and serves
to protect the load module only. This limit acts as an absolute barrier and will not permit
the product of volts and amps to exceed the setpoint. In the event that power limit is
achieved but the input voltage continues to increase, the load will respond by
decreasing the current in order to limit the total power being dissipated. An alarm
warning is illuminated on the front panel if the limit is achieved.
OVERVOLTAGE:
Each load channel is protected from operating at input voltages greater than its rating.
The overvoltage threshold is set at approximately 105% of the module voltage rating. In
the event that excessive voltage is detected, the load channel will disconnect from the
source. The load will not reconnect until the input voltage is below the overvoltage
threshold. This is considered a major fault as the load is no longer connected to the
source and all current flow has stopped. An alarm is illuminated on the front panel if the
voltage limit is achieved.
REVERSE POLARITY:
In the event that the unit is connected to a source with reverse polarity, the
undervoltage detect circuit will engage and the unit will disable the DC ON function. An
undervoltage alarm is illuminated on the front panel display.
UNDERVOLTAGE LOCKOUT:
To protect against high current and power surges, there is an undervoltage lockout.
This keeps the load inhibited until there is about .45 volts or greater on the input studs.

FRONT PANEL OPERATION
DC LOAD r--7
ON
OFF PULSE FAULT
0O
REMOTE 1:1 10
2U
LOCAL FREQ tLO 30
4CI
DUTY 3CI
AC CYCLE 60
7CI
POWER
MENU n8El
on
0
0
-6)Y1likLiA1 CHANNEL
MODES
•El
LT
PRO
•mi
CR
LOA
FCR IGH
SHORT
to
1. AC Power
2. Local Select
3. DC On
4: Flexible And Comprehensive Pulse Generation
RUN: Pulse Mode on / off
PEAK: Sets Peak Amplitude of Pulse
FREQ: Sets Frequency of Pulse
DUTY CYCLE: Sets Duty Cycle of Pulse
t10: Sets Duration of the Low Portion of Pulse
tm: Sets Duration of the High Portion of Pulse
5. Channel Select and Indicator
6. 2 Row by 16 Column Backlit Alpha-Numeric Display
7. Channel Voltmeter
8. Channel Ammeter
9. Channel Watt meter
10. Channel Status Monitor
11. Manual Adjust Knob
CI: 60.0D A
TYPE: 400V/60A
12. Manual Adjust Enable
13. Keypad For Numerical Entry
14. Mode Select
CI: Constant Current Mode Select
CV: Constant Voltage Mode Select
CP: Constant Power Mode Select
CRLOW: Constant Resistance (Low Ohm) Mode Select
CRHIGH: Constant Resistance (High Ohm) Mode Select
OCT PROG: Remote Programming Mode Select
SLAVE: Slave Mode Select - Links Channels in Parallel
SHORT: Short Circuit (Momentary Action)
15. Fault and Warning Status Indicators
Yellow: Warning
Red: Fault
16. Menu Select
17. Preset (Up to 10 Configurations)
9

ELECTRICAL CONNECTIONS
TERMINAL IDENTIFICATION
E-. E+ are the power input studs for connection to the power source. These are the large studs
on the rear of the unit.
CAUTION -Only the power source-to-load connections are to be made to these
studs.
THE TERMINAL BLOCK
SENSE- (5-) and SENSE+ (S+) -are the voltage sense terminals.
E- AND E+ - are connected internally to the power input studs. They are to be used only
as a convenient connection point for the sense terminals when sensing the voltage locally.
These terminals must not be used for load current.
Link -Analog output used by master to control slaves when multiple channels are linked.
PGM - AND PGM +Analog programming input - accepts 0 to 10 Volts to achieve 0 to full
scale loading in any mode. PGM (-) must not be more than ±200VDC from E(-).
CS - this terminal is provided for the 0 to 10 Volt current sample output signal.
THE "IEEE-488" CONNECTOR (RS232 OPTIONAL)
This is utilized for computer control
AC INPUT
This connection provides the Dynaload with its' operating power and its safety ground.
E+ AND E- WIRING TIPS
•Use short cables that are large enough in cross-section to handle the power
source's current output.
• Twist and/or bundle the E+, E- cable(s). This will reduce self-inductance.
•Whenever possible, use low inductance coaxial power cables.
•Use lugs to secure the E+, E- cables to the studs.
•Connect only the power source to load cables to the E+ & E- studs; all other
connections must be made via the terminal block.
10

EFFECTS OF CABLE LENGTH
CURRENT OSCILLATION
The Dynaload regulation loop is designed to operate at a maximum response time of 100cS. This
is not affected by manipulating the slew rate. When operating in any of the constant DC modes,
the external cable length can effect the performance of the load. If the total inductance of the
power cables is excessive, a parasitic oscillation may occur. It is always recommended to
monitor the current sample output to verify that the load is operating without high frequency
current oscillation. If this situation occurs refer to the section on effects of cable inductance on
pulse loading for recommended solutions on page 23.
LINE Loss
If the Dynaload is not configured for remote voltage sensing, the voltage display and voltage
readback will indicate the voltage present at the input terminals. This number will be effected by
the current level. Wire is a resistor, and will drop voltage as the current is increased. A general
rule of thumb is to size your wire at 500 circular mils per amp of load current. This will allow a
maximum of 10 degrees centigrade rise in temperature of the wire. The resistance of wire is
approximately 107 ohms per 1000 feet for 100 circular mils of cross-sectional area. You can use
Ohm's law (E = I x R) to calculate the line losses for your particular application.
S-, Si- WIRING TIPS
S- and S+ (Sense- and Sense+) are used to sense the load voltage. They may be connected at
the back of the Dynaload, or remotely, at the source. In any single or multiple load system, the
sense leads should be connected to the source at one and only one point.
CAUTION -Damaging current loops could result from multiple connections from source
to sense
The Dynaload is supplied with (2) metal jumpers between the S-, E- terminals and between the
S+, E+ terminals on the terminal block. These are to facilitate voltage sense wiring when sensing
locally at the load terminals.
The S-. S+ external sense leads can be connected any where between the power source and the
Dynaload. However, it is recommended that the voltage sense wires are connected to the power
source terminals. This will eliminate potential errors due to voltage drop in the cable.
The S+ voltage must be greater than or equal to the E+ voltage, and the S- voltage must be less
than or equal to the E- voltage. This is the case with normal wiring practices.
LINK
This is an analog control signal which is generated by a master module for use when controlling
slave channels. This signal is wired to each slave channel's PGM+ terminal. (The slaves' PGM-
terminals are wired to the master's E- terminal).
11

PGM+
This is the remote control input signal. 0 to 10 volts in yields 0 to full scale loading in whatever
mode and range is selected. The signal source should be referenced to PGM-. The maximum
voltage permitted from PGM+ to PGM - is 10 Volts.
PGM-
This is the signal return for the remote control input. The maximum voltage permitted from PGM-
to E- is ±200V. When linking channels, the Slave's PGM- is connected to the Master's E-.
CS
0-10V signal representing 0-full scale current. Connect an oscilloscope or other external
instruments to this terminal as external monitoring devices. This signal is referenced to E-.
AC INPUT WIRING TIPS
•The standard U.S. 3-prong cord is provided with your Dynaload.
•The voltage selector switch is located above the 3-prong AC connector.
SAFETY WARNING: Make sure that the appropriate voltage is selected before applying
power to the Dynaload.
SAFETY WARNING: The power cord provides a chassis ground through a third conductor.
Make sure that your power outlet is of the 3-conductor type with the correct pin connected
to earth ground.
•Connect the AC cord first to your Dynaload then to the utility outlet.
•Fuse replacement 3AG (3 mp, 250 volt, slow blow)
12

TERMINAL BLOCK CONNECTIONS
—CURRENT SAMPLE OUTPUT
Pcm+—REMOTE PROGRAM INPUT +
POW —REMOTE PROGRAM RETURN -
LINK —MASTER CONTROL OUTPUT +
—NEGATIVE INPUT
LIJ
—NEGATIVE SENSE
—POSITIVE SENSE
—POSITIVE INPUT
LLI
11
CD
-J
FOR LOCAL VOLTAGE SENSING, CONNECT
(5+) TO (E+) AND CONNECT (S-) TO (E-)
FACTORY INSTALLED JUMPERS ARE
PROVIDED
NOTE:
THE POSITIVE AND NEGATIVE INPUTS
ARE PROVIDED ON THE TERMINAL BLOCK
FOR EASE OF CONNECTION. DO NOT CONNECT
THESE INPUTS TO YOUR TEST SOURCE
AT ANY TIME. DAMAGE TO THE UNIT MAY
RESULT.
REMOTE VOLTAGE SENSE
th LIJ
REMOVE (E+) AN D (E ) JUhA PER S
(+)
CONNECT TO SOURCE
FOR IMPROVED VOLTAGE READBACK, USE THE REMOTE
VOLTAGE SENSING CAPABILITIES.
1. REMOVE THE JUMPERS FROM (E+) TO (S+) AND
(E-) TO (3-).
2. CONNECTTHE (3+) TERMINAL TO THE POSITIVE
OUTPUT ON THE TEST SOURCE.
3. CONNECTTHE (S-) TERMINALTO THE NEGATIVE
OUTPUT ON THE TEST SOURCE.
13

OPERATING INSTRUCTIONS
The following procedure is recommended for connecting the Dynaload:
1. AC switch should be turned off.
2. Connect DC source(s) to E+ and E- stud(s).
3. If external analog programming is to be used, connect signal source(s). Connect
link signals for paralleled modules. If IEEE-488 or RS232 (optional) is to be used,
connect the cable.
4. Connect AC power.
5. Turn on AC power; meters should come on and fans should run.
6. For manual operation: select the appropriate channel and mode via the front panel.
7. Press the DC-ON button or send the DC-ON command over the bus. This will close
the relays and connect the source to the power dissipating circuitry.
8. Enter a value and press enter. If analog programming is desired, press the EXT
PROG button. For computer controlled operation, begin sending the appropriate
commands (see IEEE-488 section for command listing). The load should now be
drawing the set current value.
CONSTANT CURRENT MODE
Some power sources such as variable power supplies are rated at a fixed maximum load current
and adjustable over a predetermined voltage range. For example: 5-30V @ 20A. If a resistive
load characteristic were used for this type of a test, it would be necessary to reset the load each
time the power supply voltage was changed in order to maintain desired load current. However,
if the load is in the constant current mode, the current is constant regardless of input voltage
fluctuations.
NOTE: Many power supplies are designed for short circuit protection by internal current
limiting and foldback therefore, the supply may not start up into a constant current
load. Accordingly, it is suggested that the Constant Resistance mode be used
when simulating short circuit protection and recovery of most power supplies,
unless otherwise specified by the manufacturer.
CONSTANT RESISTANCE MODE
The constant resistance mode regulates the load current in direct proportion to the load voltage.
There are two different resistance ranges available (HIGH and LOW) to accommodate a variety
14

of requirements. The actual available ranges are outlined in the specification section of this
manual.
NOTE: The resistance may be entered in Ohms or Amps/Volt (1/R). This option is
selected for front panel operation through the menus. For automated control,
either the AVx or the CRx commands are used.
CV - CONSTANT VOLTAGE MODE
The constant voltage mode can best be described as a shunt regulator or a zener diode. The
load will not conduct any current until the source voltage tries to exceed the voltage set point.
Once the source voltage is high enough the load will shunt current in order to regulate the
voltage. The regulating voltage is adjustable from full scale of the range selected to
approximately zero. The constant voltage mode is used to simulate a battery to a battery charger
or for special applications, such as a shunt regulator.
NOTE: Never use the constant voltage mode for testing a constant voltage source. The
regulators of the two devices will buck each other trying to gain control of the
voltage which will lead to an unstable condition.
CP - CONSTANT POWER MODE
In constant power mode, the Dynaload will dissipate a set wattage anywhere up to the maximum
power rating of the unit. The Dynaload will automatically adjust the current level inversely in
response to a change in voltage.
CAUTION: If the source voltage decays to zero volts the load will attempt to draw infinite
current.
LOCAL CONTROL
The local button on the front panel will allow the user to resume front panel control of the load
when operating with the IEEE488 bus. Pressing this button will enable all the front panel controls
and the unit will ignore all IEEE commands. By pressing the LOCAL button a second time, the
unit will return to IEEE control. This key will not function if password lockout is enabled.
REMOTE PROGRAMMING
The MCL series is analog programmable in all four modes of operation. The loading is directly
proportional to the 0-10 volt programming input. For example: If the constant current mode is
selected on an MCL488 400-60-350, a programming voltage of 5 volts is required to program the
load to 30A. Waveforms can be programmed with the remote programming input as long as they
do not exceed the capability of the load. The slew rate setting is set at the factory for 100ps for a
0to full scale transition, but is adjustable from the front panel by the menus, or through the IEEE-
488 bus.
SHORT CIRCUIT BUTTON
Pressing the short button drives the power section into a saturated (short circuit) state. This
feature is disabled from the factory and can be activated through the IEEE-488 bus.
15

NOTE: To use the short circuit feature, the undervoltage protection must be disabled
through the front panel menu, or with the UV OFF command.
CAUTION! The short circuit button is used only on power sources having
inherent current limit capability.
CAUTION! The short circuit button must not be used if the power source is
capable of delivering a current greater than the maximum current
rating.
MANUAL ADJUST
The round knob above the MAN ADJ key is utilized to manually adjust all settable features within
the Dynaload. This knob can be activated by pressing the MAN ADJ key. The resolution of the
knob can be set through the menu.
SLAVE MODE
Multiple MCL load channels may be used in parallel for greater current and power capacity. In
linked channel systems, one channel is used as the master. It is operated in the same manner
as if it were being used individually. The remaining channels are put into slave mode by either
pressing the SLAVE button on the front panel or sending the channel the SLAVE ON command.
Once linked, each slave will conduct current proportionately to the master load's current. (Refer
to page 25 for details).
MEM - MEMORY RECALL LOCATIONS
The configuration of the load may be stored in 10 settable memory locations labeled 0 thru 9. To
recall a memory location, press the MEM key on the front panel. Enter the numeric location
number, then press ENTER. When using the IEEE-488 bus the setup can be stored with the MS
command and recalled with the MR command.
NOTE: MEM- Memory Location Zero is reserved for power-up state.
MENU COMMANDS
The menu commands are accessible through the front panel by pressing the MENU key.
Continue to press the MENU key to toggle through the menu selections.
The menu features are as follows:
16

1. SR— Slew Rate limit
2. IE - IEEE bus address
3. KR— Knob Resolution for load level
4. KR— Knob Resolution for time
5. KR— Knob Resolution for frequency
6. LP— Lock Front Panel
7. PC— Change Password for front panel lock
8. AR— enter resistive load level as Ohms or amps/volt
9. TR— IEEE bus Terminator— CR or CR+LF
10. PN— Number of Pulses— 0 for continuous
11. MS— Memory Set
12. SE— Short Enable
13. PA— Pulse Amplitude entry mode— ABSOLUTE or DELTA
14. UV— UnderVoltage lockout
15. PT— Pulse Train
16. SC— System-wide DC on/off Control
17. SF— Scale Factor— pulse timing scaled down by this factor
18. Firmware version number
SLEW RATE ADJUST
The slew rate adjustment is utilized to compensate for long load input cables which could cause
oscillation or overshoot in the load due to high inductance on the loads input. The slew rate
setting is set at the factory for 100iis for a 0 to selected full scale transition. Minimum slew rate is
10 microseconds; Maximum is 40,000 microseconds, 40 milliseconds (SS) 10 milliseconds, and
.4 sec. When prompted, press ENTER to select the function, enter the numeric value in
microseconds, then press ENTER.
IEEEADDRESS SETTING
The IEEE488 primary address must be set through the front panel numeric keypad. When
prompted, press ENTER to select this function, enter the numeric address you wish the load to
respond to and press ENTER.
ENCODER RESOLUTION SETTING
The rotary digital encoder used for manual adjust can be set to different resolution settings. This
will allow the user to set for a fine or coarse knob control. This function is active in all modes of
operation, but depending on the mode, a setting which seems good in the constant current mode
may be coarse in the constant resistance mode. It is up to the users discretion to decide what
setting is appropriate.
KNOB RESOLUTION FOR TIME
The resolution for the rotary knob can be set for increased or decreased resolution. The
minimum resolution for time is .001A and the maximum is 1.00A. It is up to the user to decide an
appropriate set point. This function is active when using the T(hi) and T(lo) keys to set a pulse
function. This is inactive if using the frequency button for pulse loading.
17

KNOB RESOLUTION FOR FREQUENCY
The resolution for the rotary knob can be set when operating in the frequency set mode. The
minimum frequency increment is .001 and the maximum is 1.00A. It is up to the users discretion
to set an appropriate resolution. This function is active when using the FREQ key on the front
panel. This function is inactive if using the T(hi) and T(lo) functions.
FRONT PANEL LOCK
The Dynaload will allow the user to "lock out" the front panel controls. When locked, the front
panel controls become inactive and can only be restored by entering a password.
The factory default is 1234.
PASSWORD CHANGE
Through this screen the user can enter a password. When prompted, press ENTER. Then enter
the new password. This is a numeric entry. Then press ENTER. The maximum number of
characters is seven (7). The factory default is 1234.
AMPS/VOLT OR OHMS
This function refers to the constant resistance mode of operation. It allows the user to enter the
resistance setting as a proportional ratio based on the input voltage (Amps/Volt) or to enter a
numeric value directly in Ohms. When prompted, press ENTER to select this function. Enter the
number (1) to select operation as a ratio of AMPS / VOLT or select (2) to operate in OHMS.
Finish by pressing ENTER.
TERMINATOR
When operating using the IEEE488 control input the user must select the line terminator. You
must choose either CR (carriage return) or CR/LF (carriage return/line).
NUMBER OF PULSES
When operating in the pulse mode, the user has the option of setting a prescribed number of
pulses. When prompted, enter the number of pulses to be executed and press ENTER. The
maximum set number is 9,999,999. For continuos operation enter (0).
MEMORY SET
The Dynaload has the provision for memory presets. When a memory location is selected, the
load will remember the exact configuration and state that it currently is operating at. Items such
as DC on, voltage range, current range, mode of operation, slew setting, limit settings and set
current level will all be held in memory. To set a memory location, scroll through the menu to the
memory set window. Press ENTER to select this function. Enter a location number (0 thru 9),
and press ENTER.
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NOTE: Memory location zero (0) is the start up location of the load. Each time the AC
power is applied memory location (0) is executed.
NOTE: The memory set locations are channel specific.
There are 10 memory locations per channel. If the user sets a memory location for
channel 1, it will have no effect on any other channel. Each channel must have the
memory locations programmed individually.
SHORT ENABLE
In some applications, such as battery testing, the short circuit feature could be detrimental to the
unit under test. As a protection the short circuit function can be "Locked" to prevent use of this
function.
PULSE AMPLITUDE, ABSOLUTE OR DELTA
The pulse function will allow the user to operate in either Absolute or Delta for pulse level setting.
The Absolute mode will accept the level set with reference to a zero current baseline. The Delta
mode will assert the current level relative to the last entered baseline current. Refer to the pulse
loading section of this manual for more details.
UNDERVOLTAGE LOCKOUT
To protect against high current and power surges, there is an undervoltage lockout. This keeps
the load inhibited until there is about .45 volts or greater on the input studs. If your application
requires operation with less than .45 volts input, the undervoltage lockout may be over-ridden
through the front panel menu or UV OFF command. Otherwise, it is strongly recommended that
the UV protection be left on. To use the short circuit feature, the undervoltage lockout must be
disabled. This lockout feature is provided to prevent high current surges in the event that the
load is pre-programmed to a level and an instantaneous voltage is applied. (i.e.: external relay
closure.)
PULSE TRAIN
The internal Pulse generator can operate in both two level and three level modes. The user must
select a "0" for operation in two level pulsing or select "1" to operate in three level pulse mode.
Refer to the pulse loading section of this manual for more details.
SYSTEM WIDE DC ON/OFF CONTROL
This function will allow the user to control the DC ON/OFF function of all channels
simultaneously. By choosing the "ON" selection a single push of the DC ON/OFF button will
engage or disengage all the load channels. This is also controlled by IEEE488 commands.
Selecting the "OFF" position defines all load channels as individuals and each channel would
need to be set for an ON or OFF state.
SCALE FACTOR
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