Installation guide

Estimating Network Performance
890 USE 100 00
97
Abbreviations
TTT
(n)
Token Transmission Time (for node n)
TRT Token Rotation Time
NDOL
(n)
Node Drop Out Latency (for node n)
TN
(n)
Response Time, Normal (for node n)
TA
(n)
Response Time, Abnormal (for node n)
Calculations
TTT
(n)
= (Token Pass Time: .530 + Specific Output Time: .530 +.001(Qty of Nodes
Communicated * Qty of Registers * 16))
TTT
(master)
= (.530 + .530 + .001(15 * 32 * 16)) = 8.74 ms
TTT
(slave)
= (.530 + .530 + .001(1 * 32 * 16)) = 1.57 ms
TRT = 2(TTT
(master)
) + 30(TTT
(slave)
) = 64.52 ms
Normal Response Time (minimum):
TN
(slave)
= (1 scan Master node) + TTT
(master)
+ (1 scan Slave node) + TTT
(slave)
= 30 + 8.74 + 15 + 1.57 = 55.31 ms
Nodes 31 and 33 have this minimum normal response time.
Normal Response Time (maximum):
TN
(slave)
= (1 scan Master node) + 2(TRT) + (2 scans Slave node)
= 30 + 2(64.52) + 30
= 189.04 ms
Nodes 31 and 33 have this maximum normal response time.
Node 32 drops out, causing the following latencies:
NDOL
(31)
= 80 + 4(2) + (311) + 5(11) = 118.0 ms
NDOL
(33)
= NDOL
(31)
+ 64.52 = 182.52 ms
The dropout would create these abnormal minimum response times:
TA
(31)
= 55.31 + 118.0 = 173.31 ms
TA
(33)
= 55.31 + 182.52 = 237.83 ms
The dropout would create these abnormal maximum response times:
TA
(31)
= 189.04 + 118.0 = 307.04 ms
TA
(33)
= 189.04 + 182.52 = 371.56 ms