PCM3
Power Control Board/Cable
The PCM3 is a general purpose remote relay card for the control of power AC and DC
devices. Ideal for demanding control applications in scientific and industrial automation
systems, the KM3 permits the direct interface of relays, heaters, motors, actuators, and
a wide variety of AC and DC devices-over the full range of voltages from 10 to 280V.
The KM3 is the external relay board which is normally included with the KM2
module set. It is an option for the System 570, and can be used as a spare relay board
for the PCM2. The card is fully optoisolated and protected. All connections are made to
high-current screw terminals, and the relays are industry standard, plug-in, solid-state
elements, so the system is readily reconfigured as the application requires.
The KM3 is a remote unit which keeps potentially hazardous and noisy currents outside the system environment. The remote assembly can be mounted in a variety of
positions.
The PCM3 provides up to 16 channels of power interface. Each channel can be configured with plug in relays for DC or AC output. Each channel is short-circuit protected
with plug-in fuses, and isolated to 1OOOV AC. Control channels can switch up to 3A.
LED indicators are provided to indicate channel status. A ribbon cable is used to connect the remote card to the interface board.
WARNING: The relay card should not be handled unless all power to external circuits
has been disconnected. For maximum safety, mount the relay card in an enclosure.
User-Configured Components
The PCM3 has provisions for 16 channels of plug-in relays. Two relay types can be accomodated: the AC output relay and the DC output relay. Either relay type can be installed in any channel position.
Each channel is interfaced with two screw terminals on the remote card.
Table 1. User-Configured Components on the PCM3
Name
Screw Terminals J161
Screw Terminals f
Cable 1
Fuses
Relays
Jumper
Designation Function
CESl
See Figure 1
See Figure 1
See Figure 1
Screw Terminals for connection of AC/DC output channels (32 terminals)
External +5V power source connection (2 terminals)
Linking cable between the System 570 and the relay
card assembly (50 pin)
Per channel current limit plug-in wire fuses, 5A
Plug-in modular relays
+5V power jumper
Document Number: 500-939-01 Rev. C
PcM3-1
PCM3
Relay No.
PCM2
Channel
I I I I I I I I I I I I I I I
0 1
0 1 2
2 3 4 5
3 4 5
6 7 8
6 7
9 10 11 12 13 14 15
8 9
10 11 12 13 14 15
575/576
Port &
Channel
Port C
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
REPLACEABLE PARTS
I
I
Customer to specify quantity and type of relay(s)
~
RELAY SELECTION CHART
Port D
Connections
The KM3 provides screw terminals for 16 channels of interface. The locations of screw
terminals are marked on the remote relay card. A typical connecting scheme is illustrated in Figure 2.
Output voltage relays will operate with up to 60V for DC units; and 280V for AC units.
The maximum operating voltages of the output relays should not be exceeded or
damage to the relays will result. Outputs are fuse-protected, but currents should not exceed the rated maximum. To avoid the possibility of damage or fire, do not thwart the
fuse or expose the system to voltages greater than the maximum ratings. Signal polarity
at the screw terminals must be observed, or damage to the relay may result.
The power source, whether AC or DC, should be connected in series with the load
device and the output relay screw terminals (see Figure 2).
WARNING: When operating the PCM3 with high voltage AC and DC signals, such as
l2OV line poweq user-supplied hazardous voltages are present on both sides of the
remote assembly and at all the screw terminals. DISCONNECT ALL HAZARDOUS
VOLTAGES BEFORE HANDLING THE REMOTE UNIT INSTALL THE PCM3 IN A
PROTECTED AREA AWN FROM HUMAN CONTACT. Disconnect all high voltages
before removing or installing modular relays. Do not detach the interface ribbon cable
from the remote assembly with hazardous signals present.
CAUTION: Fuses provide protection for the relay card from l2OV low energy circuits.
However; the user must provide additional fusing for 240V line protection.
DC VOLTAGE -
SOURCE
CONTROLLED
DEVICE
I
I
Figure 2. Typical PCM3 Connections (Channel 0 Shown)
PCM3-3
Powering the Relays
The relays require 5V for operation. Normally, the System 570 power supply is used to
power the relays. This supply is provided to the relay card by installing a jumper on
the PCM 3. Connections are made with a 50-contact, flat ribbon cable with industrystandard edge-card connectors at both ends. The connectors are keyed.
It is also possible to power the relays with an external power source. Screw terminals
are provided for this purpose (see Figure 2). To operate the remote relay card from an
external source, disconnect the jumper and then connect the external power source to
the I’+” and ‘I-”
terminals.
Remote Board Configuration
By installing appropriate plug in relays, the PCM3 is easily configured to accept output
signals. Output relays are designed to switch external loads. Available relays are listed
below.
terminals. The jumper is located directly to the left of the screw
Keithley
Model ‘iLpe
500-OACl
5OO-OAC2
500-ODCl
500-ODC2
Relay Module Installation
The KM3 will be shipped with the relays specified at the time of order not installed.
At any time the user may alter PCM3 capabilities by installing the appropriate relays.
Install relays as follows:
WARNING: Remove all power from circuits connected to the PC343 relay card before
removing or installing relays.
CAUTION: Make sure the relay type agrees with expected load conditions.
1. Plug in the relay at the desired position. Make sure the mounting screw lines up correctly with the screw hole and that each relay terminal seats properly. The spacing
on the terminals is such that the relay can be installed in one direction only.
2. Secure the relay to the board with the mounting screw
3. Connect the remote relay card to the System 570 using the supplied interface cable.
MFG
OAC5
OACSA
ODC5
ODC5A
5pe
AC Output (Black) 3A, l2-14ov
AC Output (Black) 3A, 24280V
DC Output (Red)
DC Output (Red)
Ratings
3A, 10-&N
lA, lo-2OoV
Commands
The PcM3 is controlled by comman ds programmed to the System 570 power control
channels, or to the PCM2 control board. See the documentation for these devices.
l?Ch&4
Theory of Operation
The PcM3 is interfaced to the System 570 or PCM2 control card by a 50 pin ribbon
cable, with a standard edge-card IDC connector. The remote relay card is an Opto-22
PB-16, an industry-standard 16 channel solid state relay rack, with high current screw
terminal connections (two per channel), channel status LED’s and plug-in fuses for each
channel. The relays are secured by screws provided on each encapsulated relay.
Output relays contain an LED and current limiting resistor interfaced to the driving
logic. The output relay is composed of an optically coupled phototransistor, a zero
voltage circuit, and a triac output stage with a resistor-capacitor snubber circuit. In the
DC output relay, the phototransistor is coupled to an amplifier, a power transistor output (saturated on), and a protective diode.
The fuse is in the path to the scmw terminals for both input and output relays, and is
rated at 5A, l25V.
PCM3 Specifications
Channels: up to 16 output
Characteristics:
Configuration: any combination of plug-in modules (AC and DC Output)
Operating temperature: -30 to +7O”C
Status indication: LED for channel “on”
Isolation: 35W RMS channel to channel
Connections: screw terminals for #16-24 AWG wire 4’ ribbon cable to mainframe card
(TTL signals)
Dimensions: 3.5” (89mm)W x 14.7” (375mm)L x 2.2” (56mm)H
PCM3-5
Modules for PCM3
AC Output Module:
Operating Wtage:
l2-MOV AC (OAC-120)
24-28OV AC (OAC-240)
Frequency: 25-65Hz
Current: max 3A at 25”C, derate to L4 at 705C
Voltage drop: 1.6V max (device on)
Leakage: 5mA max (device off)
Power factor: up to 0.5
Switch form: 1 pole, normally open
Switch technique: optically isolated solid state switch
Switching time: Y2 cycle max (lOms at 5OHz)
DC Output Module:
DC output: ODC-60, ODC-200
Operating voltages: lo-6UV, Xl-200V
Current at 25OC: 3A, lA
Current at 7OT: IA, 0.3A
Voltage drop: 1.6V max (device on)
Leakage: 2mA max (device off)
Switch form: 1 pole, normally open
Switch technique: optically isolated solid state switch
Switching time: lms max
min 2OmA peak 50A for 1 cycle surge
PCM3-6
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