Mitsubishi Electric MELSEC iQ-R Series Safety Manual page 240

Safety refresh monitoring time on CC-Link IE Field Network
Safety refresh monitoring time is used for calculation of the CC-Link IE Field Network transmission time. This is the time that
the receiving station monitors in each connection to detect the following safety communication errors.
• Safety data sending stop due to an error on the sending station
• Safety communication stop due to an error on the transmission path, such as cable disconnection or hub failure
Set the safety refresh monitoring time with safety remote I/O module to safety stations (active side), so that the following
calculation formulas can be satisfied. The active side and the passive side use the same safety refresh monitoring time.
• Safety refresh monitoring time [ms]  TMact + (TMpas  2) + (LS  2) - a
• Safety refresh monitoring time [ms]  (TMact  2) + TMpas + (LS  2) - c
• Safety refresh monitoring time [ms] > TMact
• Safety refresh monitoring time [ms] > TMpas
TMact: Transmission interval monitoring time for a station set to the active side
TMpas: Transmission interval monitoring time for a station set to the passive side
LS: Link scan time for the CC-Link IE Field Network
a: If a station is set to the active side is RJ71GF11-T2, then a = TMact - b. For other cases, a = 0.
b: Value rounds up the calculation results of the TMact  2 to a multiple of the safety cycle time of the master station.
c: If a station is set to the passive side is either RJ71GF11-T2 or NZ2GFSS2-32D, then c = TMpas - d. For other cases, c = 0.
d: Value rounds up the calculation results of the TMpas  2 to a multiple of the safety cycle time of the local station (if NZ2GFSS2-32D, safety refresh response
processing time)
If time between a safety data reception and the next safety data reception on the receiving station exceeds the safety refresh
monitoring time, the receiving station detects a safety monitoring timeout error and stops safety communication. The safety
data to be received from the sending station is cleared in this case.
When the safety CPU module detects a safety monitoring timeout error, check if the safety refresh monitoring
time satisfies the formula above.
APPX
238
Appendix 1 Calculating Safety Response Time for System Configured with a Safety CPU