The tM-SG4 is an optional module that is used to improve the communication of RS-485 network. It provides switch selectable pull-high and pull-low resistors on RS-485 network. It also has 15-step switch selectable termination resistor such that the user can select a proper termination resistor to be connected to the RS-485 network easily. If the RS-485 network is not over 100 meters, the termination resistors are not needed. Otherwise, it may be necessary to insert two termination resistors at both end of the RS-485 network. It is not easy to calculate the value of a termination resistor on the RS-485 network. The best way to do this is to use an oscilloscope to check the RS-485 signal directly. If the impedance match of RS-485 network is OK, the oscilloscope will show a very nice square wave. If these square wave signals are distorted, the user will need to insert two termination resistors at both end of the RS-485 network.
RS-485 Interface |
Pull-high/Pull-low Resistance |
1 kΩ, 10 kΩ, 100 kΩ, Switch-selectable |
Termination Resistance |
15 Steps, 65 ~ 560 Ω |
LED Indicators |
Power |
1 Red LED as Power Indicator |
Termination Resistor |
1 Green LED as Termination Indicator |
EMS Protection |
ESD (IEC 61000-4-2) |
±4 kV Contact for Each Terminal |
Power Requirements |
Reverse Polarity Protection |
Yes |
Powered from Terminal Block |
Yes, 10 ~ 30 VDC |
Consumption |
0.5 W Max. |
Mechanical |
Dimensions (W x L x H) |
52 mm x 87 mm x 27 mm |
Installation |
DIN-Rail Mounting |
Environment |
Operating Temperature |
-25 ~ +75 °C |
Storage Temperature |
-40 ~ +85 °C |
Humidity |
10 ~ 90% RH, Non-condensing |
Termination Resistance Settings
|
120R |
330R |
470R |
560R |
Termination Resistance (Ω) |
ON |
ON |
ON |
ON |
65 |
ON |
ON |
ON |
OFF |
74 |
ON |
ON |
OFF |
ON |
76 |
ON |
OFF |
ON |
ON |
81 |
ON |
OFF |
OFF |
ON |
99 |
ON |
OFF |
ON |
OFF |
96 |
ON |
ON |
OFF |
OFF |
88 |
ON |
OFF |
OFF |
OFF |
120 |
OFF |
OFF |
ON |
ON |
144 |
OFF |
ON |
ON |
OFF |
193 |
OFF |
ON |
OFF |
ON |
207 |
OFF |
ON |
OFF |
OFF |
330 |
OFF |
OFF |
ON |
ON |
256 |
OFF |
OFF |
ON |
OFF |
470 |
OFF |
OFF |
OFF |
ON |
560 |
|
|
Pull-high and Pull-low Settings |
1k |
10k |
100k |
RS-485 Data Line Status |
OFF |
OFF |
OFF |
No pull-high/pull-low on RS-485 data line |
ON |
OFF |
OFF |
1k [ pull-high and pull-low |
OFF |
ON |
OFF |
10k [ pull-high and pull-low |
OFF |
OFF |
ON |
100k [ pull-high and pull-low |
|
|
Termination Resistance On/Off Switch
|
OFF |
Termination Resistor do NOT work. |
ON |
Termination Resistor is worked, and TR LED is light. |
|
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