Rockwell Automation 1747-SN Remote I/O Scanner - Manual (Page 99)

Publication 1747-UM013B-EN-P - January 2005
Specifications A-3
When the SLC control program detects that the remote input has been
turned on (via the scanner output image), it activates the remote
output device (via the scanner output image). Throughput is then
defined as the time between when the remote input device is
activated to when the remote output turns on.
Calculating Throughput The 1747-SN Series B Scanner’s throughput is determined by using the
formulas provided in this section.
Discrete I/O Throughput without Block Transfers (Tdm-nbt)
Present
The information in this section is used to calculate the discrete
throughput of the 1747-SN Scanner if there are no BTs occurring on
the RIO link to any chassis.
If BTs are present on the RIO link you must use the Discrete I/O
Throughput with Block Transfers (Tdm-bt) Present section to
determine your throughput. See page B-6.
The formula to calculate the maximum scanner discrete I/O
throughput without BTs present is:
Tdm-nbt = The maximum discrete throughput without BTs in milliseconds (ms)
Remote Expansion Chassis
SLC Local Chassis
Remote Chassis
Scanner
Processor I/O Module
Output Device
I/O Module
Input Device
Outputs from Modules
Inputs to Modules
Outputs to Modules
Inputs from Modules
RIO Scan
ASB Module
ASB Backplane Scan
Processor Scan
Scanner Scan
T
dm nbt –
2T
ps
2T
RIO
T
adp
T
SNo
T
SNi
T
id
T
od
+ + + + + + =