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Frequently

Asked Questions

Does the SL485 product provide power to an attached device oﬀ the terminal block? In other words, if my RS

-485

device requires power, can it obtain that power from the SNAP Link product?

★

No. The SNAP Link family requires only a tiny fraction of the power speciﬁed by the RS

-485 standard

and does not have the capability of driving an RS

485 device from the SNAP Link provided power source.

If I power oﬀ and power back on a SNAP Link product, does it forget the conﬁguration changes I have previously
applied, such as baud rate, parity, ﬂow control, UART parameters, channel, or network ID?

★

No. SNAP Link units store those parameters into non-

volatile (NV) RAM, maintaining your settings

when power is cycled.

As shipped from the factory, are the SL485 products conﬁgured to use 2

-wire or 4-

wire RS

485 cabling?

★

Factory

default settings are to assume an RS

-485 2-

wire cable. To support a 4

wire conﬁguration, the

unit must be opened and some settings on the six DIP switch box must be changed as shown in the
chapter on DIP switch settings.

I have a 3

-wire or 5-

wire RS

-485.

Do you support those as well?

★

Yes. Some documentation does not count the ground wire when discussing an RS

485 cable.

Therefore, a 2

wire isn’t counting the ground wire, while saying 3

wire does count it. They are both the

same. A 4-

wire is also the sa

me as saying 5-

wire for the same reason.

In a multipoint conﬁguration my master device shows an amber ﬂicker periodically. Does this mean it has a weak
signal strength? Can I determine the signal strength on the master unit?

★

No. A master’s A LED displ

ays a mostly green color, with a regular amber ﬂash. This display simply

indicates that the unit is the master node in a multipoint network.

★

The master does not indicate signal strength when communicating with its slaves. However, by

looking at LED C you can determine when the master unit has data transmission activity with its
attached serial device.

★

The only way to determine signal strength in a multipoint network is by looking at LED A on the slave

units to see if they have a good connection with

the master.

I need to replace the master SNAP Link unit in a multipoint setup that has been working. Must I reset each device,
or can I merely set up the new master?

★

You will need to perform a simple one

button process at each slave. This is by design s

ince you

wouldn

’

t want slave devices to automatically switch to a new master if one were one to be powered up

for a diﬀerent purpose. This is documented in the setup chapter, but the process is as follows:

Hold down the MODE button for 5 seconds until LED A begins to ﬂash red. Release the MODE button,

LED A will no longer be lit.

Click the MODE button four times in rapid succession. LED A will rapidly ﬂash amber to indicate it is

seeking a master and, upon ﬁnding one, will change to green.