Micromod Micro-DCI: 53MC5000 MicroLink - Manual (Page 27)

To reduce contention, messages from a MicroLink instrument or multiple MicroLink instruments, as
applicable, should be balanced with respect to gateway through-put at the Datalink transfer rate.
If the Datalink network transfer rate is at 28.8 Kbaud, the External Input Module entries of each
node on the MicroLink network should limit accesses to gateway Datalink instruments to at least 3
entries apart (e.g., Tasks 0, 4, 8, etc.); and if the transfer rate is at 9.6 Kbaud, accesses should
be limited to at least 6 entries apart (e.g., Tasks 0, 7, 14, etc.).
8.4 ACCESSING MICROLINK NODES FROM THE DATALINK
SUPERVISOR-PC UNIT OR HOST
8.4.1 SETTING DATALINK SUPERVISOR-PC UNIT PARAMETERS
Prerequisites are SUPERVISOR board firmware must be revision 4.3 (or higher) and a 53MC5000
PCS functions as a gateway in Datalink responder mode.
Datalink SUPERVISOR-PC unit Parameters B04 through B07 are each set to 3 when the corre-
sponding instruments are on the MicroLink network, and B08 is always set to 0.
8.5 GATEWAY CABLING
The gateway is cable connected to the MicroLink and Datalink networks for Datalink interrogator or
responder mode operation as follows:
• MicroLink Connection - If the gateway is to be installed in Datalink interrogator or
responder mode, connect it to the MicroLink network as illustrated in Figure 4-1.
(Standard MicroLink cabling for a 53MC5000 PCS.)
• Datalink Connection, Datalink Interrogator Mode - If the gateway is to be
installed in Datalink interrogator mode, connect it to the Datalink network as
illustrated in Figure 8-3 for cord set rear terminal board units or Figure 8-4 for
standard rear terminal board units. (Reversed Datalink cabling for a 53MC5000
PCS.)
Proper cabling of the gateway in Datalink interrogator mode is just like a Datalink
SUPERVISOR-PC unit: the T+ and T- of the gateway are wired to the R+ and R-
respectively of the other Datalink instruments. The transmitted signals of the
gateway (gateway T+ T-) are received by the instruments (instrument R+ R-), and
the transmitted signals of the instruments (instrument T+ T-) are received by the
gateway (gateway R+ R-).
• Datalink Connection, Datalink Responder Mode - If the gateway is to be installed
in Datalink responder mode, connect it to the Datalink network as illustrated in
Figure 8-5 for cord set rear terminal board units or Figure 8-6 for standard rear
terminal board units. (Standard Datalink cabling for a 53MC5000 PCS.)
Section 8. Configuring the 53MC5000 PCS as a Gateway
28