The Feeder Modules measure the fault current level in the branch circuits that are protected. This module uses standard I-Gard current sensors Type T2A, T3A, T6A and T9A. It is equipped with a form C 10A output Relay that can be used for breaker control. The DSP-DFM detects two fault levels. Firstly it detects the single fault, which creates a System Alarm condition, and secondly through a priority level system it provides breaker control to disconnect the least important circuit breaker. Communications is provided by a 4-wire RS-485 network connection from a jack located at the rear of the DSP-DM Display module. The communications protocol supported is MODBUS RTU, which is a master/ slave system with selectable baud rates from 4800 to 19200. The DSP supports the MODBUS function Read Holding Registers only, without exception support. Additionally it will support remote RESET using the Force Coil function.

2 APPLICATION

The DSP system is used in conjunction with I-Gard, Alarm Resistor Unit Type DDR2. The DDR2 matches the DSP-DSM input circuits to the system voltage and is available in 4 types as follows:
Type DDR2-1 DDR2-2 DDR2-4 DDR2-6
* Also used with potential transformers up to 13.8KV
System Voltage 120V* 240V 480V 600V
The DDR2 provides output voltages VAG, VBG, VCG that are proportional to the phase to ground voltage and also voltage VNG that is proportional to the neutral resistor voltage. ( i.e. Total leakage/fault current of the system) On large systems provision is usually made to ground the system using a current-limiting resistance (I-Gard Type OHMNI-PM or NGR). On ungrounded systems there is always leakage capacitance to ground from each line. Re-striking ground faults may cause an excessive build up of line to ground voltage due to this capacitance. It may be stabilized with the addition of a grounding resistance, thus preventing costly breakdown of insulation. The Type OHMNI-PM is connected between ground and the star point of the transformer on Wye systems. On Delta systems an articial neutral device (I-Gard Type DDAI) is required to provide a star point. Both OHMNI-PM and DDAI devices are selected for appropriate current let-through, i.e.: The current, which will ow to ground, if there is a direct short from line to ground (on any one phase).

NOTE: A good Rule-of-Thumb for Resistor current selection is 1 ampere per 2000KVA, if no surge capacitors are on the system, and 1 ampere per 1000KVA with surge capacitors. For further information please refer to www.i-gard.com/appguides.htm
DDAI and OHMNI-PM devices are available for continuous currents of 1 ampere to 10 amperes for most systems. For further information regarding the use of these devices refer to: Instruction Manual Type DDAI Articial Neutrals Instruction Manual Type DDR2 Alarm Resistor Units Instruction Manual Type OHMNI-PM Neutral Grounding Resistors C-430EM C-440EM C-450EM

3 INSTALLATION

A typical installation will include for each power source (transformer/generator) 1 DSP-DM, 1 DSP-DPS, 1 DSP-DSM and a number of DSP-DFM Feeder Modules as required with 1 for each branch protected. Additionally there will be a DSP-PM pulsing resistor to ground the system. A voltage-sensing resistor DDR2 is required for the DSP-DSM input, as well as one current sensor for each DSP-DFM for current detection. See Table 3.1 for typical requirements. TABLE 3.1 SYSTEM MODULE REQUIREMENTS Catalog Number DSP-DM DSP-DPS DSP-DSM DSP-DFM OHMNI-PM DDR2 DDAI T Description Display Module Power Supply System Voltage Module Feeder Module Pulse Equipped Resistor Voltage Sensing Resistor Articial Neutral Toroidal Current Sensor No Required/System 1 As required 1/ Circuit Required only for delta system 1/Feeder Module
TABLE 3.2. STANDARD RIBBON CABLES Length 365cm (12ft) 150cm (5ft) 5cm (2 in.) 30cm (12 in.) Function DSP-DM to DSP-DPS DSP-DM to DSP-DPS Module to Module connection Module to Module connection Catalog Number DRC-365 DRC-150 RC-3 RC-30
DSP modules are mounted on a 35mm DIN Rail generally located at the rear wall of a switchgear compartment. They should be mounted side by side and connected with 20-conductor ribbon cable in a daisy chain conguration. This applies to the DSP-DPS, DSP-DSM and DSP-DFM modules only.
DSP (Outline Dimensions). Care should be taken not to over tighten the 8-32 nuts used to retain the DSP-DM It will be necessary to provide a reliable power source (which is not interrupted by operation of the DSP output contacts) for control power. The supply should be 100-240 V AC/DC. The control supply must be fused by 1 Ampere fuses as shown in Fig. 4.1 a (Connection Diagram). Ideally the alarm, warning bell should be connected to a separate control supply from the DSP (see para. 8.3.1).

4 WIRING

No. 14 or No. 16 switchboard wire is used for all current sensor, control and DDR2 connections, which need not be shielded. 4-wire shielded cable should be used for the serial communications, however. A typical wiring schematic is shown in Figure 4.1a. Sensor wiring is not generally limited by length and may be up to a kilometer without degradation of performance, since the sensor is a current source. Sensor wiring should be run in separate conduit from Power wiring. The recommended sensor wiring connections are shown in Figure 4.2. Two wires should be run from each sensor X1 and X2 as indicated to prevent cross coupling between Modules. If existing wiring does not allow this connection because of common connection at X2 as has been common in some installations, then the G terminals of the DSP-DFM modules should be connected as shown in Figure 4.3. Ribbon cables are available in different lengths as shown in Table 3.2. For other lengths contact I-Gard. The DRC-cable from the DSP-DM to the DSP-DPS, apart from being different in length, also differs in the orientation of the connector. This allows the cable to be run easily from the DSP-DM towards the DSP-DPS power supply. The RC-cables are used for Module to Module connections and are short in length. Note the orientation of the plug as marked on the DSP-DM display module. If a second row of modules is installed on another DIN rail, the last module on the right can be connected to the last module on the right on the second row using the RC-30 cable. Either slot can be used on the DSP-DFM feeder modules for connection.

CAUTION! THE SYSTEM WILL ALLOW YOU TO SELECT INVALID NUMBERS OUT OF RANGE, WITHOUT WARNING, BUT THE RESULTS WILL BE INDETERMINATE.

6.3 Feeder Module

SETUP FM? Y/N

FEEDER SEL TRIP ON PRIOR

Figure 6.4 Feeder Module Set-up
Following the OHMNI-PM set-up the display prompts for Feeder Module Set-up. Select Y to enter the Feeder Module setup screen as shown in Figure 6.4 (b). After installation of Feeder Modules they must be given identication numbers from 01 to 50 (maximum) so that the Display unit can determine which module it is talking to. Each module must have a different number. To change the number, use the pq arrows to increase/decrease the digit under the ashing cursor and ut to change digits.

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The Display module is the master module and is constantly sending requests for data from each feeder module from 1 to 50. The Feeder Modules compare the request I/D with their own I/D to decide whether or not they are being asked for data. If the I/D is the same then that Feeder Module replies with Current, Priority and Status information to the master Display Module. Therefore it is very important that there are not modules in the chain with the same I/D. The Feeder Select program checks for duplicate I/D when ENTER is pressed following an entry of FEEDER SEL xx. If an existing I/D is detected, the screen will indicate as in Figure 6.5.

I/D IN USE TRIP ON PRIOR

Figure 6.5 I/D Check indication
In this case the user must enter a different I/D number before proceeding further. The user is allowed another chance to enter a valid I/D number before the cursor moves to TRIP ON/OFF selection. This permits the TRIP and Priority of previously set modules to be changed while retaining the same I/D number.
CAUTION! IT IS ENTIRELY POSSIBLE FOR THE USER TO ENTER A NUMBER OUTSIDE THE RANGE 01 TO 50 AND THE SYSTEM WILL ACCEPT IT WITHOUT WARNING, DATA WILL NOT BE COLLECTED FROM SUCH MODULES, ALTHOUGH THEY WILL CONTINUE TO PROVIDE FAULT PROTECTION.
Typically, the numbers will be in the sequence 1,2,3,4. but they can be in any order physically. The Display Module does not care. The identication number, however, must be known for each feeder circuit since the Display does not support the use of Text Labelling to identify circuits. Note: This can be done with user-provided software from the RS-485 network if required or by use of the DSP.net server package downloadable from the I-Gard web site. See communications section. Press ENTER to select the Ident Number. The cursor then drops to TRIP ON setting which is the normal setting. To disable the TRIP function of the Feeder Module press t arrow in which case no priority is required to be set and the Screen of Figure 6.6 is presented. If the TRIP feature is to be retained (normal setting) pressing ENTER will then allow the user to set the priority of the selected Feeder I/D. To change the number, use the pq arrows to increase/decrease the digit under the ashing cursor and ut to change digits. The range of priority numbers is from 00 to 15 with 0 being a lower priority than 15. In the case of Priority numbers it is OK to use the same number more than once unlike the I/D numbers, so that unimportant circuits can all be set to 00, for example.

13 I-GARD

When the desired priority for a given I/D number has been selected, press ENTER. You will then be prompted with the screen of Figure 6.6
PUSH FM BUTTON AND THEN ENTER
Figure 6.6 Feeder Module Set-up
At this point select the DSP-FM module that is to have the I/D that was set-up, and press the TEST button on that module. The red FAULT light will turn on to indicate the received I/D signal. Press ENTER to complete the process. The DSP-DM will display either of the following messages depending on whether or not the setup was successful.

FM ACCEPTED CONTINUE

a) Feeder Module Successful

FM NOT ACCEPTED CONTINUE

b) Set-up Not Successful Figure 6.7
Press u to exit the screen and the DSP-DM will allow the user to set-up more Feeder Modules with screen 10 a) and b)

FM ACCEPTED ANOTHER? Y/N

a) DSP-DM allows further Feeder Module set-up
FM NOT ACCEPTED ANOTHER? Y/N
b) If previous set-up had not been successful Figure 6.8

I-GARD 14

If more Feeder Modules need to be set-up then select Y and ENTER to repeat, or if not select N and ENTER to exit the Feeder Module Set-up and enter the PULSE Set-up. The Pulse set-up screen allows the pulsing mode for fault location to be changed for different frequencies and mode of operation. The screen of Figure 6.9 is shown.

6.4 Pulsing

SETUP PULSE? Y/N
Figure 6.9 Pulse Set-up Request
PULSE INVRT? OFF FREQ 0 LOCK? OFF
Figure 6.10 Pulse Mode Set-up
Select Y to enter the Pulse Set-up Screen which looks like Figure 6.10 which will show the existing set-up of the PULSE module. The pulsing information is stored in the DSP-DSM, which must be installed during setup. Press t to toggle the setting ON or OFF as required.

6.4.1 Invert / NDR MAL

The output from the DSP-DPS module is connected to a solid state relay. Normally (non Inverted operation) the output from the + and - terminals of the DSP-DPS module is zero prior to any pulsing operation, and the relay is OFF. If Inverted mode is selected, then this voltage is 12V dc. And the relay is, therefore, energized continuously. The choice of NORMAL or INVERTED operation depends on how the Grounding Resistor current is connected. If the Grounding resistor consists of two series or two parallel resistors (one main resistor and one pulse resistor) with the pulse resistor to be switched in and out by a solid state relay then the following two options exist.

a) Pulse Up current

Pulsing upwards means to increase current from IGmax 5A to IGmax 10A, for example. In this case the pulse resistor is normally OFF and the INVRT OFF would be selected. Pulsing would then change the current to a higher level from 5A to 10A alternating when a 100% fault exists.

b) Pulse Down current

Pulsing downwards means to reduce the current from IGmax 5A to IGmax 2.5A, for example. In this case the pulse resistor will be Normally ON and thus the INVRT ON mode would have to be selected. This will mean that the solid state relay will be ON when the system is normal (no fault) and will open when pulsing is started thus reducing current. See Diagram 6.11 for examples of both series and parallel connected resistor arrangements.
NOTE: the INVRTed mode is the mode used with the standard OHMNI-PM resistors as supplied by I-GARD.

15 I-GARD

RG 2.5A

RP 2.5A

+ INVRT OFF

+ INVRT ON

a) Pulse UP Parallel Resistors

5 2.5 0

b) Pulse Down Parallel Resistors

c) Single Resistor

INVRT ON
0 a) Pulse UP Parallel Resistors
Figure 6.11 Typical Examples of Pulse Circuit Connection

I-GARD 16

6.4.2 Pulsing Frequency
Press ENTER when the selection is chosen. The cursor will then move to the FREQuency position. Press pq to select a pulse frequency from 0 to 9 with frequency increasing with the number selected. It is not important to know exactly the frequency selected, however, Table 6.1. Indicates the frequency for each setting. TABLE 6.1 PULSING FREQUENCY SELECTION Select Freq Hz.

6.4.3 Interlock

1 1.25

2 1.50

3 1.75

4.2.00

5.2.25

6 2.50

7 2.75

8 3.00

9 3.25
Press ENTER after a value has been selected and the cursor moves to the interLOCK position. The interlock prevents pulsing from occurring when there is no fault on the system. Press t to toggle ON or OFF and then ENTER to complete the Pulse set-up.

6.5 Alarm Relay

For the next Setup the user will then be presented with the option to change the operation of the MUTE function. The MUTE button normally disables the Alarm Relay and the local Beeper Alarm when pressed to following a fault. However, the designer might use the Alarm Relay for some other function, for example another contactor or cooling fan operation of the grounding resistors. In this case it is undesirable to MUTE the relay. For this reason the operator may choose to disallow the MUTE button to change the state of the Alarm Relay. The Screen of Figure 6.12 is presented.

ALARM RELAY Y/N

Figure 6.12 Alarm relay Setup
Selection of Y provides the option selection screen of Figure 6.13.

MUTE ALARM RLY ENABLED

Figure 6.13 Alarm relay Options
The default is with the Alarm Relay MUTE control Enabled to allow Silence control of an external Horn system. Pressing button will toggle the ENABLED to DISABLED to defeat the MUTE switch operation of the Alarm Relay and allow it to be used for other purposes which depend on whether or not the system is in a Faulted condition.
NOTE: This does not affect the local Beeper function which will still continue to be MUTEd by the MUTE button.

17 I-GARD

That completes the set-up. At this point you may be presented with the option of saving the values changed or not with the screen of Figure 6.14.

SAVE CHANGES Y/N

Figure 6.14 Save Screen
Note: You may not see this screen. If no changes were made in the set-up, or changes were made to the Feeder Module set-up or the Pulse Set-up, it will not appear. This is because those changes are actually saved in the DSP-DFM and DSP-DSM respectively. The changes selected will be saved in non-volatile EEPROM memory until the next time the set-up is changed and re-saved. Pressing ENTER after selecting Y/N.

6.6 Self Test

At this point the user is asked if SELF-TEST is desired with screen of Figure 6.15.

SELF-TEST? Y/N

Figure 6.15 Self-Test Prompt
The user can just press ENTER to ignore and return to the Home Screen, or select Y ENTER to perform Self-Test on the system. See Self-Test section for details. See Section 9 for Self-Test.

7 OPERATION

7.1 Screen Navigation
Normally with an un-faulted system and recent RESET, the Display Module will display the Normal Home screen of Figure 7.1 with a green NORMAL light on the front panel and no Alarm. The System Module will indicate a green NORMAL light and the DSP-DFM modules will show no light indication at all. The DSP-DPS supply will also indicate POWER with a green light when power is supplied to it. The yellow PULSE light may, or may not, be ON, depending on whether, or not, the INVERTed mode of operation has been selected for the pulse operation. If the Inverted Mode is selected the Pulse Relay will be normally energized and will deenergize with each pulse. The PULSE light will indicate when the pulse relay is energized. In the Normal pulse mode, the light will be OFF and will light with each pulse. The Display Module will indicate the Normal Home screen as in Figure 7.1. I-GARD RESISTORS HRG SYSTEM OK
Figure 7.1 Normal Home Screen

I-GARD 18

Pressing u takes the user to the Screen 2 which shows the total system ground current IG as a percentage of the maximum ground current allowed by the grounding Resistor. As a reference, the setting for the Maximum Ground current is shown as IG max (5A in the example of Figure 7.2). The IGmax current must agree with that of the Neutral Grounding Resistor of the system. If it does not then the OHMNI-PM set-up must be repeated.

IG SYSTEM A =10% 100%(IGmax) =05A
Figure 7.2 System leakage current lG
NOTE this screen can only be seen when the system does not have a fault as will be seen.
Press u again to view Screen 3 which is the Feeder Module screen in Figure 7.3 below. It allows the user to examine the status of the installed DSP-DFM modules. Feeder Modules are identied by their I/D numbers from 1 to 50 and may be scrolled through with the pq keys. Priority settings can be observed (10 in this case) and Ground Current Igf for the Feeder is displayed as a percentage of the maximum Ground Current of the System. A reading of - - would represent a direct short to ground for the Feeder while 00% represents no current leakage at all. STATus is indicated as well which shows whether or not the Feeder Module is OK (leakage below 50%), FLT (faulted) leakage greater than 50% or TRP (Tripped) which may happen if a second fault caused current in the sensor to exceed 100A for 200mS or more.
FDR 01 PRIOR 10 1Gf 07% STAT OK
Figure 7.3. Feeder Current IGf
Only those DSP-DFM modules that have valid I/D settings will indicate successfully. All others will indicate as though they were not installed with blank characters in the display elds.
NOTE: to identify which DSP-DFM is which, if not sure, the user can push the I/D/TEST button on each DSP-DFM until the Status indicator on the Feeder Screen shows TST. This will be the FM selected and the I/D can be read on this screen.
If the TRIP function was defeated in the Setup Mode, then the Feeder Modules that are disabled will indicate with a screen similar to Figure 7.4
FDR 01 TRIP OFF! 1Gf 07% STAT OK

Figure 7.4 Trip Defeated

19 I-GARD

7.2 Pulsing

Press u to move to the next screen. This is the Pulsing Control Screen. It appears as in Figure 7.5. PULSE ON/OFF PULSING OFF

Figure 7.5 Pulse Control

This screen is only used to turn on the Pulsing System for fault location. It will cause the OHMNI-PM Grounding Resistor value to be modulated to permit readings to be easily detected on portable current probes. Pulsing is toggled ON and OFF with the t button. The bottom line of the display indicates the Status of the Pulsing Module. It should change to ON when pulsing is ON. Note: If the Pulsing cannot be turned ON, it could be because the InterLOCK setting has been set to ON in the Pulse Set-up. In this case Pulsing cannot be turned ON unless there is an actual fault on the system. This can be easily changed in the Set-up conguration. If Pulsing is selected ON, then it will remain ON until turned OFF again or RESET is pressed. The Home screen will remind the Operator that pulsing is ON with the screen of Figure 7.6.

PULSING ON HRG SYSTEM OK

Figure 7.6 New Home screen indicates Pulsing ON
12V DC Pulse current is sent from the DSP-DPS + and - terminals to the DSP-PM Grounding Resistor to energize the solid-state relay in the Resistor and by-pass part of its elements to modulate the Ground Current (if any). When nished with the Pulse operation press u to exit and return to the Home Screen.

8 ALARM INDICATIONS

If a fault greater than 50% of IG develops somewhere on the system, and Alarm is declared by the System Module, this causes several events to occur.

LED indications

DSP-DM display module green NORMAL changes to red ALARM DSP-DSM system module red ALARM light DSP-DFM Fault Indication is enabled to provide indication if Fault is detected by Feeder Module (Fault may not be detected by a Feeder Module - if it is on the Main Bus for example)

I-GARD 20

Alarms Alarm Relay (Form C) on DSP-DPS will operate to energize customers alarm device (Horn etc.) A local beeper will sound in the DSP-DM to indicate the fault The Alarms both local and external can be cancelled by the MUTE button, which is actually the key when in the Alarm Screen. It will not work on the Feeder or Pulse Screens. Once cancelled the Alarm will remain OFF until about an hour after the last button has been pressed on the keypad of the DSP-DM when it will resume if an Alarm condition still exists. RESET will also cancel the MUTE effect.

Display

The Home screen will change to an Alarm Screen which will indicate which phase is faulted, and the branch circuit that is affected, with a screen similar to that of Figure 8.1.
FAULT PHASE A FEEDER 01 IG 67%

Figure 8.1 Alarm Screen

The faulted Feeder is identied by I/D number. The Total System Current IG will indicate the system current as determined by the voltage from the DDR2 resistor unit (See 8.1 above). Note this may not be exactly the same as the Feeder Current Igf that is indicated in the Feeder Module Screen since the sum of all leakages will not necessarily be the same as that of one particular Feeder branch. Feeder fault information can be determined by pressing u to move to the Feeder Screen. The Faulted Feeder (if any) can be located by scrolling with pq keys to the faulted one. The current reading Igf relating to that feeder is shown. It should exceed 50%. The FLT status will also conrm that this is the faulted circuit. In addition, there will be an Alarm Indication on the faulted Feeder Module which is indicated by a continuous red LED. In this situation it then becomes necessary to determine the source of the fault. In some cases this might be known problem but if the fault is not quickly identied then the risk is that a second fault may develop and cause shutdown of one of the breakers. To locate the fault easily the Pulse system can be turned on using u to enter the Pulse Control screen. See Fault Finding section.

21 I-GARD

If no Feeder Faults are identied the Display Module will indicate BUS FAULT as in Figure 8.2 to indicate this special situation. In this case the probability is that there is a fault upstream of the current sensors and usually indicates a fault in the main transformer or bus duct which supplies the switchgear.
FAULT PHASE A BUS FAULT IG 67%

Figure 8.2 Bus Fault

This screen may also be observed under other situations as well. For example if a fault develops on a faulty DSP-DFM or the Module is missing or a Feeder has no protection on it at all, the same indication will result. Another situation might be on a main-tie-main system with two DSP systems and a fault develops on one side of the gear. The DSP-DM on the other side will indicate Alarm with a BUS FAULT if the tie is closed since it does not see any DSP-DFM on its side with a fault.

9 SELF TEST

Basic functionality testing of the system can be done without interrupting circuit breakers. To enter the Test the operator must be in the Home Screen and without a fault on the system at the time. Press SETUP button. Using the ENTER key press 4 times until the SELF-TEST screen is reached, Select Y and ENTER to access the Self-Test. The operator is prompted with the TEST SYSTEM test as in Figure 9.1

TEST SYSTEM? Y/N

Figure 9.1 System-Test Prompt
To check the SYSTEM Module DSP-DSM, select Y and ENTER otherwise just push ENTER to move to the Feeder Module Test. If the SYSTEM was selected when ENTER is pressed, the Red Alarm lights on System Module and Display Module will light and both the local and remote Alarm devices will sound. Check that the MUTE button silences the Alarms effectively. The prompt gure 9.2 for Feeder Module DSP-DFM automatically appears at this time. Select Y or ENTER to perform the Feeder Module Test. Pressing ENTER will return the display to the Home Screen.

TEST FEEDER? Y/N

Figure 9.2 Prompt for Feeder Test

I-GARD 22

The second line of the display will indicate that it is ready for a Feeder Module Test with the screen of Figure 9.3.

TEST FEEDER? Y/N FM NO.

Figure 9.3 Feeder Module Test
At this point the operator may press any DSP-DFM TEST button and if it is good the Display will respond with the I/D number of the selected Feeder Module and acknowledges with OK as in the example of Figure 9.4

25 I-GARD

DSP MODBUS output structure
Two functions are supported Read Holding Register (03) Set Coil (05) There are 154 registers available, which can be accessed by an external host system. This document summarizes the format and function of these registers. The request from the master is always 8 bytes long and are as shown in Table 13.1. TABLE 13.1 MODBUS RTU STANDARD 8 BYTE HOLDING REGISTER READ FUNCTION (03) Unit I/D Function Starting Address High 00 Low 01 No. of Registers requested High 00 Low 02 CRC High nn Low nn
All bytes are in hexadecimal. Numbers above are, for example, a request for 2 registers only, starting from address 01. CRC checksum is 16 bit CRC as described in MODBUS information. The high bytes are not used in any requests. If successful the DSP will return the message shown in Table 13.2. TABLE 13.2 RETURNED INFORMATION STRUCTURE FOR HOLDING REGISTER REQUEST Unit I/D Function No. of bytes High 02 Low 00 Data 1 High 02 Low 00 Data 2 High 01 Low nn CRC High nn Low
Register contents are shown in Tables 1 to 3 as follows.
NOTE: Register number is shown in decimal but must be sent in hexadecimal form in the request.
The only write functions presently supported in the DSP system are RESET control and PULSE ON/OFF which will require the use of Set Coil function in MODBUS. The format for Setting is as shown in Figure 13.3 TABLE 13.3 REQUEST TO WRITE TO SET A BIT ON A REGISTER (MODBUS FORCE COIL) Unit I/D Function High Coil Address Low 00 High 00 Force Coil Low ff CRC High 00 Low nn nn

I-GARD 26

In this case there will only be two coils (actually DSP functions) Coil No Name Reset Pulse Force Coil Data ff00 =on ff00 =on 0000=off 0000=off
The response of Table 13.4 will conrm the request TABLE 13.4 RETURNED INFORMATION FROM DSP FOLLOWING A FORCE BIT REQUEST Unit I/D Function Coil Address High 00 Low 00 Force Coil High ff Low 00 CRC High nn Low nn
Which is just an echo of the request. The registers can be read either one at a time or in a continuous block up to a maximum of 100 registers at a time. There are times when the DSP processor will not be able to respond to a request since it is busy with other tasks and no response will be returned. For this reason it is recommended to request the maximum number of registers used by the system in a single request. Since the DSP is set up to 50 current registers, 50 Status registers and 50 Priority registers followed by the System function registers, it is best to read the data with three consecutive requests.
NOTE that the DSP will not respond to requests if the DSP-DM is in the SETUP mode.

The Feeder Module currents Igf values are contained in the rst 50 registers as follows. The values range from 0x00 to 0xff although maximum for a rst fault condition will be 0x64 or 100%. Table 13.5 lists the register addresses in the MODBUS convention.

27 I-GARD

TABLE 13.5 FEEDER MODULE GROUND CURRENT ADDRESSES Register No 40025 Contents Feeder 1 Igf Feeder 2 Igf Feeder 3 Igf Feeder 4 Igf Feeder 5 Igf Feeder 6 Igf Feeder 7 Igf Feeder 8 Igf Feeder 9 Igf Feeder 10 Igf Feeder 11 Igf Feeder 12 Igf Feeder 13 Igf Feeder 14 Igf Feeder 15 Igf Feeder 16 Igf Feeder 17 Igf Feeder 18 Igf Feeder 19 Igf Feeder 20 Igf Feeder 21 Igf Feeder 22 Igf Feeder 23 Igf Feeder 24 Igf Feeder 25 Igf Format 0x00nn Register No. 40050 Contents Feeder 26 Igf Feeder 27 Igf Feeder 28 Igf Feeder 29 Igf Feeder 30 Igf Feeder 31 Igf Feeder 32 Igf Feeder 33 Igf Feeder 34 Igf Feeder 35 Igf Feeder 36 Igf Feeder 37 Igf Feeder 38 Igf Feeder 39 Igf Feeder 40 Igf Feeder 41 Igf Feeder 42 Igf Feeder 43 Igf Feeder 44 Igf Feeder 45 Igf Feeder 46 Igf Feeder 47 Igf Feeder 48 Igf Feeder 49 Igf Feeder 50 Igf Format 0x00nn
Feeder Module Status is represented by ve valid states as follows: 0x00 = OK 0x01 = Faulted feeder 0x02 = Feeder Tripped 0x03 = Test Button pushed 0x0f = Not available The registers following return two bytes The rst byte is always 0x00 with the second returning status in hexadecimal as above.

I-GARD 28

TABLE 13.6 FEEDER MODULE STATUS ADDRESSES Register No. Contents Function 40075 Feeder 1 Status Feeder 2 Status Feeder 3 Status Feeder 4 Status Feeder 5 Status Feeder 6 Status Feeder 7 Status Feeder 8 Status Feeder 9 Status Feeder10 Status Feeder 11 Status Feeder 12 Status Feeder 13 Status Feeder 14 Status Feeder 15 Status Feeder16 Status Feeder 17 Status Feeder 18 Status Feeder 19 Status Feeder 20 Status Feeder 21 Status Feeder 22 Status Feeder 23 Status Feeder 24 Status Feeder 25 Status Format 0x00nn 40100 Register No. Contents Function Feeder 26 Status Feeder 27 Status Feeder 28 Status Feeder 29 Status Feeder 30 Status Feeder 31 Status Feeder 32 Status Feeder 33 Status Feeder 34 Status Feeder 35 Status Feeder 36 Status Feeder 37 Status Feeder 38 Status Feeder 39 Status Feeder 40 Status Feeder 41 Status Feeder 42 Status Feeder 43 Status Feeder 44 Status Feeder 45 Status Feeder 46 Status Feeder 47 Status Feeder 48 Status Feeder 49 Status Feeder 50 Status Format 0x00nn

29 I-GARD

TABLE 13.7 FEEDER MODULE PRIORITY ADDRESSES Register No. Contents Function 40125 Feeder 1 Priority Feeder 2 Priority Feeder 3 Priority Feeder 4 Priority Feeder 5 Priority Feeder 6 Priority Feeder 7 Priority Feeder 8 Priority Feeder 9 Priority Feeder10 Priority Feeder 11 Priority Feeder 12 Priority Feeder 13 Priority Feeder 14 Priority Feeder 15 Priority Feeder16 Priority Feeder 17 Priority Feeder 18 Priority Feeder 19 Priority Feeder 20 Priority Feeder 21 Priority Feeder 22 Priority Feeder 23 Priority Feeder 24 Priority Feeder 25 Priority Format 0x00nn 40150 Register No. Contents Function Feeder 26 Priority Feeder 27 Priority Feeder 28 Priority Feeder 29 Priority Feeder 30 Priority Feeder 31 Priority Feeder 32 Priority Feeder 33 Priority Feeder 34 Priority Feeder 35 Priority Feeder 36 Priority Feeder 37 Priority Feeder 38 Priority Feeder 39 Priority Feeder 40 Priority Feeder 41 Priority Feeder 42 Priority Feeder 43 Priority Feeder 44 Priority Feeder 45 Priority Feeder 46 Priority Feeder 47 Priority Feeder 48 Priority Feeder 49 Priority Feeder 50 Status Format 0x00nn

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TABLE 13.8 SYSTEM FUNCTION REGISTERS Register Function System IG current System Status Format 0x00nn 0x00nn Description nn = 0-100% Total System leakage current IGt Nn 01 = Normal no fault 10 = A phase low 20 = B phase low 40 = C phase low 70 = All phases low 82 = A phase faulted 84 = B phase faulted 88 = C phase faulted 40153 Pulse setup 0x00nn nn lower byte is a composite byte upper nibble is Mode of operation while lower nibble of nn is pulse frequency 0 9. nn 0n = Normal, interlock OFF 1n = Inverted, interlock OFF 2n = Normal , interlock ON 3n = Inverted, interlock ON 40154 Pulse Status 0x000n n 0=Pulsing OFF 1=Pulsing ON

14 SPECIFICATIONS

14.1 Power Requirements DSP-DPS
100-240V, 50/60Hz or DC, 25VA
14.2 Maximum Ratings DSP-DPS
Control voltage Dielectric Relay contacts to chassis Control terminals to chassis DC output maximum rating

250V AC/DC

1500V rms. for 1 minute 1500V rms. for 1 minute 22W max for +5, +12 and 12V supplies

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Settings DSP-DSM System Module Alarm Level Pickup Trip Level Inhibit

14.3 Pulse Set-up

50% of system Ground Current IG 25% of system Ground Current
Pulse Rates 0 to 9 Setting in 0.25Hz increments 1.0,1.25,1.50,1.75, 2.0, 2.25, 2.50, 2.75, 3.0, 3.25Hz. Pulse Modes Pulse Interlock Pulse Output current

14.4 DSP-DFM

Normal, Inverted Normal, Interlocked with Fault Detect. 0.5A @ 12V DC
Ground Current Settings IG Trip Level Current Trip Level Delay Priority Levels

14.5 Contact Ratings

1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16A 100A 10xP +200mS (Where P=Priority setting) (16 settings)

DSP-DFM Trip Contacts Form C SPDT DSP-DPS Alarm Contacts Form C SPDT

14.6 Performance

10 amperes, 240V AC resistive 8 amperes, 240V AC resistive
DSP-DFM Pickup accuracy Trip Level accuracy DSP-DSM Alarm Level Accuracy 10% of IG Meter accuracy 10% of IG 10% of system let-through current 10A
NOTE: Accuracy based on single resistance fault, at nominal line voltage, without system capacitance.
Temperature Range: Standards
Operating temperature 0C-+50C CSA File number LR65287 UL E232710

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Physical Dimension
Weight 1.5kg See Fig. 17(next)
I-Gard reserves the right to change specications of its products without notice.

15 OUTLINE DIMENSIONS

Figure 15.1 shows typical Dimensional details of the Polymeric enclosures used for the modules. All have the same cross-section dimensions but with different widths W as shown.

58.00mm

Figure 15.1 DIN Rail Mounted Modules
Module DSP-DFM DSP-DSM DSP-DPS DSP-CAS DSP-CA
W 35mm (1.377 in.) 70mm (2.755 in.) 155mm (6.102 in.) 70mm (2.755in.) 70mm (2.755in.)

33 I-GARD

Drill two holes A No 36 TAP or No 23 Clearance 6-32 Screw
4.25 (108mm) 6.50 (165mm)
Figure 15.2 DSP-DM Display Module with cut-out detail

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GND GND
20 conductor Ribbon To DSP-DM
20 conductor Ribbon To DSP-DSM
Figure 15.3 DSP-DPS Power Supply Connections
20 conductor Ribbon To DSP-DPS
20 conductor Ribbon To DSP-DFM
Figure 15.4 DSP-DSM System Module Connection
1000:1 Zero-Sequence Current Sensor
20 conductor Ribbon To DSP-DSM 20 conductor Ribbon To Other DSP-DFM
Figure 15.5 DSP-DFM Feeder Module Connection

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J3 RS-485 Communications J1
To Next Device, or Converter
20 Conductor Cable to DSP-DPS
Figure 15.6 DSP-DM Display Module Connections
16 ADDITIONAL INFORMATION
If you require more information or experience problems with your equipment that persist after taking the steps identied in this manual, please contact I-Gard Customer Service.

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17 INSTRUCTION MANUALS
C-101 Stoplight High Resistance Grounding System Manual

Ground faults cause havoc on plant production processes, shutting down power and equipment and critical loads. Ground faults disrupt the ow of products through manufacturing processes and cause data loss in computer centers leading to hours or even days of lost productivity. Ground faults pose potential health and safety risks to personnel, creating hazards such as equipment malfunctions, re and electric shock. High Resistance-Grounding (HRG) is becoming more prevalent in industrial and commercial electrical power systems because it eliminates un-scheduled downtime due to ground faults, and improves personnel safety by preventing ground faults from escalating into arcash incidents. Resistance Grounding is highly recommended for generators, to protect them from damage due to excessive ground fault currents.

O H M N I

S Y S T E M
The DSP SYSTEM is designed to detect the event of a single ground fault, signal an alarm, and point to the affected branch or feeder. Thus maintenance can be immediately alerted to the problem and an operator dispatched to locate the fault to isolate it promptly. The DSP system can assist in locating the fault with a pulsing fault location circuit. In the event of a second ground fault, the DSP acts quickly to prevent loss of two feeders by selectively tripping the lower priority feeder only.

the power to protect

DIN rail mounted high resistance grounding system Multi-Feeder ground alarm indication with double fault protection Integral resistance pulsing and MODBUS communication for remote monitoring Inrush detection restraint prevents nuisance tripping on high inrush loads
With its separate easy to read digital display and modular design, the DSP OHMNI can be expanded to 50 feeders for large installations, each with a dedicated feeder module and sensitive zero-sequence current sensor. MODBUS communications allows the operator to remotely monitor which feeder has faulted and to monitor the leakage currents of all feeders for trending purposes.

Technical Specications

Power Requirements Control voltage Dielectric 100-240V, 50/60Hz or DC, 25VA 250V AC/DC Relay contacts to chassis Control terminals to chassis Alarm Level Pickup Trip Level Inhibit Contact Ratings 50% of system Ground Current IG 25% of system Ground Current DSP-DFM Trip Contacts Form C SPDT DSP-DPS Alarm Contacts Form C SPDT Performance DSP-DFM Pickup accuracy Trip Level accuracy DSP-DSM Alarm Level Accuracy Temperature Range Standards 10% of IG 10% of system let-through current 10A 10 amperes, 240V AC resistive 8 amperes, 240V AC resistive 1500V rms. for 1 minute 1500V rms. for 1 minute Alarm Level
Operating temperature 00C 500C CSA File number LR65287 UL Listing E232710
I-Gard 7615 Kimbel Street, Unit 1 Mississauga, Ontario Canada L5S 1A8

65287 E232710

Toll Free 1.888.737.4787 Phone 905.673.1553 Fax 905.673.8472 www.i-gard.com