Micromod Micro-DCI: 53MC5000 MicroLink User Manual
Page 11
4. Access the Process Control Station External Input Module (IB 53MC5000, Section 4)
and sum the reciprocals of the PSCAN values for each peer-to-peer task with PMOD
≠
0 to
determine the TPS for that node. (Each configured task in the External Input Module is 1
load; therefore, if TPS = loads/scan time, then TPS = 1/scan time. For example, if there
are 4 instrument reads listed in the External Input Module with PSCAN values of 2, 4, 2,
and 1, then the node TPS = 1/2 + 1/4 + 1/2 + 1/1 = 2.25.)
Repeat Step 4 for each PCS node on the network.
5. To determine the network TPS: total the TPS for all of the nodes, add this to the total
SUPERVISOR-PC unit TPS obtained in Step 2, and the total TPS obtained in step 3 for PC
units with the 53WS5000 package installed. Reference Table 3-1 again to verify that the
network TPS just calculated is still valid (not too large) for the data rate (Mbits/s). If the net-
work TPS just calculated exceeds the maximum TPS number at the data rate listed in Ta-
ble 3-1, then some transactions may not be completed within the specified scan time;
network loading should be reduced by increasing the scan time of some SUPERVISOR-PC
units.
Table 3-2. SUPERVISOR SCAN Times
SCAN
Time
Seconds
1 Mbit/s
0.5 Mbit/s
0.25 Mbit/s
1
200
100
50
2
400
200
100
3
600
300
150
4
800
400
200
5
1000
500
250
Note: Table 3-2 assumes there are no gateways (described in Section 8) interconnecting
Datalink and MicroLink networks. Transactions Per Second for a given Scan Time and
Data Rate are reduced if there is cross network communication through gateways.
Section 3. MicroLink Network Sizing
9