Campbell Scientific SDM-SIO1 Serial Input/Output Module - Manual (Page 10)

SDM-SIO1 Serial Input/Output Module
2.2.2 SDM-SIO1 Voltage Specifications
Connection Minimum
Voltage
(1)
Nominal
Voltage
(1)
Maximum
Voltage
(1)
Power supply, +12 V
connection
(2)
7 V 12 V 20 V
RS-232 input threshold
Low 0.8 V – –
RS-232 input threshold
High – – 2.4 V
RS-232 input absolute
maximum
(2)
– ±15 V ±18 V
RS-232 input
resistance 3 kΩ 5 kΩ 7 kΩ
RS-232 output voltage
swing
(3)
±5 V ±5.4 V –
RS-232 output
absolute maximum – – ±13.2 V
RS-485 input
(Differential) 200 mV (4) – 6 V
RS-485 output
(Differential) 2 V (at 50
Ohms) – –
SDM lines (high level) 4.3 V 5 V 5.7 V
SDM lines (low level) 0 V – 0.7 V
(1) Values are volts D.C. (except resistances)
(2) It is NOT recommended that the user runs their SDM-SIO1 at maximum
ratings for extended periods of time
(3) Assuming a worst case 3 KΩ load
(4) It is not recommended that the user allows such low input voltages as there
will be an increased chance that external noise may cause errors in the
incoming data
2.2.3 EMC Compliance
The SDM-SIO1 has been tested and shown to comply with IEC 61326. The
device incorporates transient and surge protection that is designed to meet
IEC61000-4-5, level 4, providing the device is adequately grounded.
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