Instruction Bulletin
30598-811-01B1
January 1997
Replaces 30598-811-01A1 (6/91)
ROM871
64-Function Reed Relay
Output Module
Class 8030
30598-811-01B1
January 1997
ROM871 64-Function Reed Relay Output Module
Specifications
INTRODUCTION
SPECIFICATIONS
CAUTION
EQUIPMENT DAMAGE
Outputs per module
64
Outputs per common
8
Voltage range [a]
5 to 32 VAC/VDC
Max. current [ a]
To avoid improper handling of equipment:
Max. surge current
• Never remove device while power is ON. Turn power
supply switch to OFF and wait until all indicating lights
are off before removing.
• Disconnect power before changing field wiring.
• Do not subject to static discharge. This module
contains electronic components that are very
susceptible to damage from electrostatic discharge.
Failure to observe these instructions can result in
equipment damage.
The Class 8030 Type ROM871 Module is a 64-function
reed relay output module with 8 isolated commons (one
for each group of 8 points). Reed relays are used to switch
many different kinds of loads, such as pilot lights, lamps,
motors, solenoids, relays, coils, or electronic circuits. Dry
reeds, however, cannot handle the surge currents or
inductive loads of many field devices. Review and apply
“Application Considerations” on page 3 before installing
your module. The ROM871 module has 4 removable
terminal blocks, which provide easy field wiring
connections.
Each group of 8 points is fused. The fuses are accessible from
the side of the module (Figure 1). Each output point has a
corresponding red LED indicator that lights when the
on-board processor issues a command to energize an output.
400 mA/output; 2.5 A/common
[a]
8 VA (AC); 8 Watts DC
Type and related isolation:
Common to common:
Between common and logic:
1400 VDC
1400 VDC
Initial relay contact resistance
150 milliohms
Relay contact life
200 x 106 operations
(max. w/o load)
Max. recommended reed relay
100 Hz
operating frequency
Turn-ON time
1.5 ms (nominal)
Turn-OFF time
1.5 ms (nominal)
Fuse
Wickman 19374K, TR5-T
Status of the LED operation
Red LEDs light when receiving
associated ON signal from the
on-board processor
Typical power requirements
1120 mA (75% duty cycle)
1410 mA (100% duty cycle)
Ambient temperature
0-60° C (operational)
Storage temperature
-40 to +100° C
Humidity rating
5-95% relative humidity
(non-condensing)
Weight
Approx. 3.3 lbs; 1.5 kg
Dimensions (W x H x D)
1.5 x 12.8 x 6.6 in (3.8 x 32.5 x
16.8 cm)
Used with these rack
assemblies:
RRK100, RRK200 (except slot 1),
RRK300 (except slots 1, 17 & 18)
HRK100, HRK150, HRK200
(register slots only)
CRK210, CRK300
(register slot only)
DRK210, DRK300
(register slot only)
GRK100, GRK210
(register slot only)
Module compatibility:
Compatible with RIM731 Input
Module
The ROM871 module may be placed in any slot of a
register rack (except slots 1, 17, and 18 of an RRK300) or
the register slot of a digital rack.
LEDs
0.5 A
Max. power rating (switching)
[a] Observe the maximum power rating for all voltage and current
combinations, for example, 0.3 A at 24 V AC/DC.
Access to fuses
through side panel
Terminal
Blocks
Figure 1: ROM871 Module
TYPICAL WIRING
All field wiring is connected to the 4 removable terminal
blocks, located on the lower front of the module. These
terminal blocks support 64 outputs with 8 isolated
commons (one common for each group of 8 outputs). The
output channel termination points are numbered 1-8 and
9-16 on the terminal blocks. The 8 isolated common points
per module (2 per terminal block) are labeled 1A through
8A. Each common is associated with the 8 outputs directly
above it on the terminal block. See Figure 2 for an
illustration of typical wiring. The terminal blocks are
keyed to prevent inserting them in the wrong order.
© 1997 Square D All Rights Reserved
2
30598-811-01B1
January 1997
ROM871 64-Function Reed Relay Output Module
Wiring & Application
Programming. In the DISPLAY mode of the Class 8010
Type SPR2xx and SPR3xx CRT Programmers or
SY/MATE® or SY/MATE Plus® programming software,1
all contacts and coils associated with register-slotmounted digital I/O modules are shown with the prefix
(R) in front of the address. These R-designated contacts
and coils are associated with actual inputs and outputs –
not the contacts and coils associated with internal relays.
Important Relay Protection Requirements. When using
reed relay contact output modules, you must understand
and apply limitations and protection requirements. This
precaution ensures reliability and long life. Because reed
relays operate with very low contact closure and spring return
forces, they are likely to fail in a closed position if either the reed
relays are improperly applied or if the reed relay safeguards are
not used. A reed relay that is damaged by improper loading
must be replaced. Otherwise, even if relay protection is added
subsequent to the initial damage, it will probably fail in a closed
position.
With proper application and relay protection, the
hermetically-sealed dry reed relays used in the ROM871
will provide many millions of reliable operations.
Figure 2: Typical Output Wiring
APPLICATION CONSIDERATIONS
Removing the Terminal Blocks. Remove the terminal
blocks from the module by prying gently with a
screwdriver. This allows you to replace the module
without disturbing field wiring.
Forcing. When the Type ROM871 Output Module is
located in the same rack as the processor, the only
processors that allow the outputs to be forced ON or OFF
are Model 300 Series E or later, the Model 400, the Model
450, the Model 600, and the Model 650. The Model 500 and
700 processors do not support the forcing function.
Instead, they rely on the forcing capability in the local
interface module to provide this function. When the
output is mounted in a remote rack, the outputs may be
forced ON or OFF by any processor.
Size of Wiring. Depending on the size and routing of
wiring to the terminals, you may need to remove an
adjacent terminal block before removing an I/O module.
Each terminal accommodates one #14 or two #22 AWG
wires.
Securing the Module. After inserting the module in the
rack, tighten the captive screw at the bottom of the
module for a secure connection.
Processor Key Switch Position. The output relays are
only allowed to operate when the processor key switch is
in the RUN position. The relays are disabled in the HALT
and DISABLE OUTPUTS positions. The LEDs operate in
both the RUN and DISABLE OUTPUTS positions and are
disabled in the HALT position.
Load Characteristics. Loads that can cause failure in reed
relays are either inductive or capacitive in nature. Purely
resistive loads are ideal for reed relay switching, requiring
no protection, but unfortunately are rarely found in the
industrial environment. (Even a purely resistive load with
a long wiring run will present a load that has both
capacitive and inductive elements.) The characteristic of
the load(s) must be considered for the reed relay
protection circuitry to be effective. Because the
applications of the ROM871 vary widely, the module
doesn’t have any on-board protection circuitry. You must
select and apply the appropriate protection circuitry.
Inductive Loads. Inductive loads include any device that
has a coil, such as a relay, motor starter, or motor. This
inductance results in the voltage rising to a very high level
(sometimes hundreds of volts) as the contacts open. This
high voltage level results in arcing across the contacts and
damage to the contact points.
To ensure the contact integrity for the full rated life of the
reed relay, install Single Inline Package (SIP) modules into
the terminal blocks to suppress voltage spikes when the
relay contacts are opened. Table 2 lists the part numbers of
the SIP module kits. The kits contain 8 SIP modules for all
64 output channels. Select a kit with the closest voltage
rating to the application. Do not, however, exceed the
voltage rating of the kit. For example, select a 24 VDC kit
for a 14.4 VDC application.
1
When using SYM323 Series B and SYM324 Series A or later, all contacts and
coils associated with digital I/O modules are shown with the prefix (I) in
front of the address if it is an input, or (O) if it is an output or contact of an
external output.
© 1997 Square D All Rights Reserved
3
30598-811-01B1
January 1997
ROM871 64-Function Reed Relay Output Module
Wiring & Application
Table 1:
SIP Module Kit Part Numbers
System Voltage
SIP Kit Part No.
6 VDC
8030 CBP150
6 VAC
8030 CBP154
12 VDC
8030 CBP151
12 VAC
8030 CBP155
24 VDC
8030 CBP152
24 VAC
8030 CBP156
32 VDC
8030 CBP153
32 VAC
8030 CBP157
Install pin 1 of the SIP (indicated by the dot) into terminal
block position 1 or 9, as shown in Figure 3.
Capacitive Loads. Capacitive loads cause a higher-thannormal current, called in-rush surge current, to flow
through the contact points for a brief period of time. If the
total in-rush surge current is great enough, the contact
points will heat up and be damaged. Typical capacitive
loads include long wiring runs (over 15 feet), incandescent
bulbs, and power supplies. In-rush surge currents can
occur at a much higher rate than the steady-state current
(or wattage) rating. For example, a tiny incandescent bulb
such as those used in push buttons yields a steady state
wattage of 1 W. As it lights, however, this bulb’s surge may
rise as high as 20 W. The ROM871 module is rated for 500
mA of surge current or a maximum of 8 W of power being
switched. Table 2 shows the maximum switching current
for each system voltage range. Verify that the total surge
current requirements for the devices powered by the relay
output are below these limits.
NOTE: In-rush surge currents can be much higher than the
steady-state current rating. If incandescent bulbs are used, in-rush
currents are 10 to 20 times the steady-state current.
Table 2:
Maximum Switching Current
Supply
Voltage
Max. Surge
Current
Min. Load
Resistance
6 VAC/DC
500 mA AC/DC
12 ¾
12 VAC/DC
500 mA AC/DC
24 ¾
24 VAC/DC
330 mA AC/DC
72 ¾
32 VAC/DC
250 mA AC/DC
128 ¾
If the current limit in Table 2 is exceeded, you must use a
limiting resistor in series with the output load (Figure 4),
to ensure that output current limit is met. If the load
resistance is not high enough, add another series resistor
to the load, to reduce excess current flow.
Figure 4: Output Current Limiting
Resistor Wiring
Figure 3: SIP Module Installation
© 1997 Square D All Rights Reserved
4
ROM871 64-Function Reed Relay Output Module
Fusing & Module Keying
30598-811-01B1
January 1997
8.
9.
10.
11.
FUSING
CAUTION
EQUIPMENT DAMAGE HAZARD
• Disconnect power before changing fuses.
Reinstall the module in the rack.
Tighten the module’s captive screw.
Plug the terminal strip back into the module.
Reapply power to the SY/MAX system.
MODULE KEYING
• Never use a fuse with a rating that exceeds 5 A.
Failure to observe these instructions can result in
equipment damage.
Each common is individually fused at 5 A (Wickman TR5
series). The fuse may be replaced with one of a lower
amperage rating to more closely protect the device
controlled by the output. Figure 5 shows the orientation of
the fuses inside the ROM871 module.
Register slot connectors, whether in a digital or register
rack assembly, have factory-installed keying pins, located
between pins 4 and 6 of the connectors. They ensure that
only register modules can be plugged into register slots.
Each register slot connector may be keyed to accept only
one type of register module. An optional keying pin kit,
Class 8030 Type CBP104, is available for this purpose. The
keying pin location for the Type ROM871 Output Module
is between pins 26 and 28 (Figure 7). Use the keying pin
insertion tool to install the keying pin (Figure 6).
Maximum fusing: 5 A at 250 V (Wickman TR5 series)
Note: You may use lower fuse rating to provide more appropriate
protection for the control device, but never use a fuse with a
rating above 5 A. Record the specific fuse values in the white
circles on the ROM871 fuse access panel.
Figure 6: Module Keying
Figure 5: Fuse Arrangement for ROM871
The on-board fusing is designed to protect the module
and may be too large to protect an individual load or relay
from overcurrent damage. It is a good idea to provide
individual overcurrent protection for critical loads.
To replace fuses, follow these steps:
1. Turn off the SY/MAX processor by turning the
processor keyswitch to the “HALT” or “DISABLE
OUTPUTS” position.
2. Remove power from the SY/MAX rack and turn off
the control power to the terminal strip on the front of
the module.
3. Remove the plug-in terminal strip from the front of
the module.
4. Loosen the captive screw at the bottom of the
module.
5. Remove the module from the SY/MAX rack.
6. Remove the 4 screws holding the cover on the side of
the module.
7. Change the fuse(s) and replace the cover and screws.
5
© 1997 Square D All Rights Reserved
Figure 7: Inserting the Keying Pin
ROM871 64-Function Reed Relay Output Module
Installation & Addressing
30598-811-01B1
January 1997
INSTALLATION IN A RACK ASSEMBLY
The ROM871 module may be installed in a register slot of
a Class 8030 Type CRK, DRK, GRK, HRK, or RRK rack
assembly. The module receives 5 VDC power and ground
from the edge connector at the back of the rack.
Disconnect power from the rack assembly before
installing or removing the module from the rack.
To install the module in a rack:
1. Insert the module into the register slot until it is firmly
seated against the metal stud, located just above the
connector strip at the back of the register slot.
2. Tighten the captive screw at the bottom of the
module to ensure the module is secure.
To remove the module from a rack:
When a SY/MAX Model 300 processor is mounted in an
RRK200 or RRK300 register rack, slots 9 or greater cannot
be addressed and may not be used for any I/O modules.
Since slots 9 or greater cannot be addressed by the
Model 300, they may be used to power any register
module that only requires power and that does not require
registers, such as the D-LOG or SY/NET® modules.
Slots 17 and 18 of an RRK300 rack (lower right-most slots)
are not addressable by any SY/MAX processor. The
ROM871 module cannot be used in these slots.
SIMPLIFIED SCHEMATIC
Figure 8 illustrates one of the 64 circuits within the
ROM871 Output Module. Terminal 1A is common to the
first 8 outputs within the module.
1. Loosen the captive screw at the bottom of the module.
2. Pull the module out of the slot using the finger tab at
the top of the module.
REGISTER USAGE FOR RACK ADDRESSING
Each ROM871 module requires 4 registers in the system.
They must be assigned to the slot in which the module is
inserted. The first register assigned to the module is
associated with the 16 points having common terminals
1A and 2A (upper left terminal block). The second register
is associated with terminals 3A and 4A (lower left
terminal block), and so on, through the fourth register,
associated with 7A and 8A.
Figure 8: Simplified Schematic of One Output Circuit
The ROM871 is a microprocessor-based I/O module and
each register assigned to it contains a status field (bits
25-32), which provides diagnostic information about the
module’s microprocessor. The status field information
(Table 3) is accessible with SY/MAX programming
equipment. lists the possible ROM871 error codes. If any
of error codes are present (AD is normal operation), a
module or system error condition is present. Refer to the
SY/MAX Troubleshooting Instruction Bulletin (#30598-502)
for more information.
Table 3:
ROM871 Status Field Definitions
Status Bits
Hex
[a]
32 31 30 29 28 27 26 25 Value
Description
1
0
1
0
1
1
0
1
AD
Normal operation
0
0
0
1
0
1
0
0
14
No card acknowledged in slot
0
1
1
0
1
0
0
1
69
Diagnostics in progress
0
1
0
1
0
0
0
0
50
EPROM failure
0
0
0
0
0
0
0
0
00
Slot not addressed
0
1
0
1
0
0
1
1
53
Watchdog time-out
SY/MAX, SY/NET, SY/LINK, SY/MATE, and SY/MATE Plus are registered
trademarks of Square D Company.
Electrical equipment should be serviced only by qualified electrical maintenance
personnel. No responsibility is assumed by Square D for any consequences
arising out of the use of this material.
6
© 1997 Square D All Rights Reserved