JUMO Wtrans p Notice De Mise En Service page 65

For this reason, we recommend using a maximum of 16 transmitters for a transmission interval of 1 s.
Selecting a larger transmission interval allows for a significantly larger number of transmitters.
Estimating the maximum number of transmitters
If more than the recommended 16 transmitters are to be used with a transmission interval of 1 s, select
a higher transmission interval to prevent an increased error quota.
Example:
16 transmitters with a transmission interval of 1 s = 32 transmitters with a transmission interval of 2 s
The calculation displayed in the next example applies when the number of transmitters is to be increased
further.
Example:
16 transmitters with a transmission interval of 1 s = 48 transmitters with a transmission interval of 3 s
(in theory)
However, from a transmission interval of ≥ 3 s, the wireless telegram is transmitted twice. This means
the number of transmitters that can be used is cut in half.
16 transmitters with a transmission interval of 1 s = 24 transmitters with a transmission interval of 3 s
(effective)
The same occurs with a transmission interval of ≥ 60 s. As of this transmission interval the wireless tele-
gram is transmitted three times.
External transmitters
External transmitters may transmit on the same radio frequency. If, for example, the transmitter and an
external transmitter transmit their wireless telegrams at the same time, the wireless telegram is de-
stroyed. No error is detected because the transmitters cannot check their own transmission while trans-
mitting.
Electrical devices
In a harsh industrial environment, wireless telegrams can be destroyed, for example, by frequency con-
verters, electrical welding equipment, poorly-shielded laptops/PCs, audio/video devices, electronic
transformers, electronic ballasts, etc.
Error fade-out
Lost telegrams (caused either by external interference sources or by collisions when using a large num-
ber of transmitters) can be faded out at the receiver by the wireless timeout parameter and do not cause
error messages. The value received last is retained over 2 to 10 transmission intervals and only then is
the wireless timeout alarm activated (display "----").
NOTE!
In the event of collisions caused by an excessive number of transmitters, observe and, if necessary, cor-
rect the factors "number of transmitters", "transmission intervals", and, on the receiver, "wireless time-
out".
4 Transmission range
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