Procentec ComBricks, User Manual

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ComBricks User Manual v6.4.0 | January 18| © PROCENTEC 130/219
Table 8 - Bus Parameters for PA projects, in bit times
Baud rate Tslot
(only DX)
MaxTSDR
(only DX)
Tslot
(with DP-V1)
MaxTSDR
(with DP-V1)
9.6 – 19.2 kbps 330 145 1500 150
45.45 kbps 640 480 640 480
93.75 kbps 2500 1000 2500 1000
187.5 kbps 3200 1500 14000 1400
500 kbps 8500 4000 38000 3700
1.5 Mbps 25500 11500 110000 11000
These are ‘worst case’ values. It is recommended to examine the timing of your installation and decrease the
bus parameters to a suitable value for your network.
The DP-V1 table has higher slot times than the Data Exchange table because DP-V1 telegrams can be up to 240
bytes. Such a telegram takes a long time to be generated, and therefore the Tslot needs to be larger.
In small applications it is required to set a value for the Tset parameter. Usually a value of 95 is sufficient.
Because of the longer Slot Time and MaxTSDR, it is also recommended to set the Watchdog to at least 2
seconds. This is normal in PA networks.
In Coupler mode, the module has no bus address on either side. When configuring your PA network there is no
restriction in the use of addresses for field devices, although most configuration tools do not allow address 0, 1
and 2.
12.5 Physical layer
12.5.1 Connecting a PA segment
The bottom of the PA module has two identical connections for the PA trunk. These are connected 1-on-1. As
stated above the integrated termination is ON when power is connected to the PA module, which means that
the PA module is always the start of a segment. The automatic termination cannot be disabled. Most
installations will use only one connector. In that case it does not matter which connector is chosen. See
Fig. 86
for an example.
It is also possible to use the second connector as a stub line, as shown in
Fig. 87 . Do not terminate the end of a
stub line, otherwise the PA segment has too many terminations.