GE CM6 Hardware Reference Manual page 71

GE Intelligent Platforms – CM6 Hardware Reference Manual, Fourth Edition
Table 33: COM1 electrical characteristics
Signal
Maximum data rate
C = 1000 pF R =3 KΩ
L L
Vi (Receiver)
Vo (Driver)
VT+ (Receiver input threshold)
VT- (Receiver input threshold )
COM2 RS422/485 Interface
The RS422/485 interface uses the Maxim® MAX1484 Transceiver chip with
following electrical characteristics:
Table 34: COM2 electrical characteristics
Signal
Maximum data rate
Vi (driver/receiver absolute maximum)
Differential driver output (no load)
Differential driver output (R=50 Ω
RS422)
Differential driver output (R=270 Ω
RS485)
Driver output short current
Receiver differential threshold
Receiver hysteresis
Receiver input resistance
Isolation
The Isolation of the Ethernet outputs is limited to 500 V peak against logic
ground (GND) and any other supply voltage.
By itself the onboard logic ground (GND) and the front panel/chassis frame
ground (FGND) are isolated on the CM6 with a layout distance of more than
0.3 mm in all PCB layers. Also standard racks (our starter cage, too) connect
both grounds at the power supply for safety reasons.
Voltage
150 kbit/s
-25 V ... +25 V
min +/- 5 V
max +2.7 V
min -2.7 V
Voltage
12 Mbit/s
-8 V ... +12.5 V
max 5 V
min 2.0 V
min 1.5 V
min 35 mA, max 250 mA
min -200 mV, max 200 mV
typ 70 mV
min 96 kΩ
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